A 1.8L 412 engine build thread

[raygreenwood]

Update for May 5th 2018

So to get started on finishing the oil pump….a little information I left out in the last section that you can do now.

Since we are going to be lapping the inside deck of the pump body to reduce plate to gear clearance, before you start measuring the depth so you can know how much you have lapped away as you proceed….lap the outer edge of the pump body just a little bit to make sure there are no ugly dips that will throw your measurements off greatly

Removing the idler shaft and locator bushing from the plate:

So I made a wooden jig from a 2” x 4” and clamped it in the vise….

So the plate sits flat

I used a brass drift and a hammer to drive out the idler shaft

NOTE:
1. Mark the end that is in. The outer shaft section is polished smooth

2. Mark the depth that the shaft is pushed in from the outside. This one was 0.040”

3. VERY IMPORTANT: This shaft had to be POUNDED OUT. It was very tight and probably did not need to be pinned but I do this anyway for long term safety.

BUT….if your idler shaft is very loose and can be easily pushed out or wiggles in the bore….your pump plate is scrap and should not be used. A loose shaft will allow the pressure between the gears to drive the gear apart making the shaft more loose.

Shaft is out

Using a sharp, clean edged, flat face punch…you will fins that the locating bushing has a very slight ledge from the outside and can be tapped out easily with a few taps.
Alternate to each side. Clean up any burrs you make later with a needle file or sandpaper.

Locating bushing is out

Get a quick measurement of the plate thickness just for information. You are going to lap until the marks in the plate are gone anyway but this is a good insurance to make sure you lap evenly.
The machine work around each bolt hole on the outside is a little crude so you will get four slightly different measurements by each hole. Just number the plate with a sharpy and write them down. Its just insurance.

I used machinist layout dye. I always do this just for the start of lapping to get an idea if I am keeping things straight.

I am using valve grinding compound on glass to do the rough/large/fast removal

For the final polish I am using this. These are really nice. You can buy them at most good hobby shops. They are polyester film based wet/dry abrasive. Very uniform and tough.

http://www.ksmetals.com/19.html

For some reason the sanding films do not appear on their website but you can order them on ebay and in other places and most serious hobby shops sell them in varieties that range from 0.5 microns up to 150 grit.

By the way…0.5 micron is 60,000 grit and 1.5 micron is 13,000 grit. Serious sanding and polishing films.

So apply some lapping compoundevenly to the face of the plate and some on the glass.

IMPORTANT: When lapping….DO not move a circular flat object like this plate around in circles.

Move it in straight lines ONLY like the red arrow in the pictures for whatever number of strokes you want. Then turn the part a measured increment and repeat the same number of strokes. Work all the way around full circle.
I did 10 strokes on each hash mark.

Why is this important?

Because the inner area of any surface being turned in a circle is smaller in diameter (red circle and lines)…than the outside perimeter.

So with each revolution the outer areas pass over a much greater distance of abrasive paper…wearing MUCH faster than the inner area…which will wear the part into a “cone” shape.

I did this on purpose for an example shown above. Notice the marks are worn away faster where the red arrow is.
This was not a problem for this. It was less than .0002” so I just re-coated it and lapped it correctly to straighten it out.

After the first revolution…which was 16 angle changes as shown in that lappong diagram with 15 strokes on each axis. 240 strokes total.

You can just barely see a little bit of gear marks left. This took maybe 10-15 minutes. I stopped at the halfway point and added more lapping compound.

I finished it off with 10 strokes on each axis…160 strokes total, on 600 grit sanding film on glass.

The finished plate.

NOTE: you MUST wash these parts with hot soapy water at least twice and then rinse wit ha hot solvent like carb cleaner.

The gears:

NOTE: We already noted the swirl marks in the gears. By the way…these marks are NOT caused by debris.

These are machine marks in the original gears. Any really heavy grooves caused by debris in these end face areas almost always show a ding or chip in the edge of the gear where a piece of metal or grit was jammed between the gear face and the plate or pump body.

I measure the gears first. The driven gear in this pump was 0.0004” shorter. Not enough to worry about.

The same lapping method. Note that I marked the starting gear tooth with a Sharpy marker. These gears have 9 teeth so I used 9 axis changes and 20 strokes each (steel is harder than aluminum and takes more work)…180 strokes on each face.

Same on the 600 grit on glass

The faces are nice. I did not do the shaft side of the driven gear. There is just no way to do it right and its not a big problem.

The inner pump body deck:

This is my lapping plate. I was hoping my machinist buddy would have made me a tool steel one by now…but this works just fine. You can probably do about five pumps with this.

This is made from a 6” x 6” x 0.250” thick piece of Mic-6 aluminum jig and tool plate. You can get a 6” x 6” plate from McMaster Carr for about $17. The inner bore of the pump body is about 2.6”. I clamped this piece of metal down and used a cheap 2.75” bi-metal hole saw to cut out a clean, oversized circle.

I then tapped the guide hole with an 8mm x 1.25 tao and installed a bolt. Put the plate in the drill press. You really need a drill press for this..but you can do it wit ha drill motor locked in a vise…be careful. Turn the speed up to high and take an angle grinder with a 50-60 grit flap wheel and run it against the egde.

Every 2 minutes….pull the plate and mandrel out with a pair of pliers and cool it off in cold water. It easily gets to 300°-400°F. Measure it.

When you get to within about .005” to .008” of the plate fitting in the oil pump body….you MUST cool it all the way down to get an accurate measurement.
When you get within about .002”…stop using the angle grinder and use a fine file tilted back toward the mandrel side a few degrees. This angles the edge of the plate away from the pump body so you do not lap where you do not need to. Stop when it just fits with about .002” to .004” clearance…into the pump body.

IMPORTANT NOTE: unlike the flat plate and the gears….the distance between the outside edge diameter compared to the farthest point inward….of the inner ledge of the pump body….is not far enough apart to make a big difference in sanding/grinding speed.

SO…when lapping this part…to keep the lapping plate flat and wearing evenly…ONLY turn it around in complete revolutions…not in short back and forth strokes.

Apply lapping compound to plate bottom and a small amout to the ledges inside the pump with a Q-tip. Wipe off the edges of the lapping plate.

You can use a ratchet. It will take you about 20-30 minutes. Stop and add a little more water or lapping compound about every 5 minutes

You can use a cordless drill at low speed…about 125-150 rpm. I used a drill and finished in about 8 minutes worth of work.

Note how the lapping compound dries out fast

BUT with a drill you must stop every 1-2 minutes and add lapping compound. I stopped after two sessions of 4 minutes with two applications of lapping compound and washed the pump body and measured the depth.

And here it is done. Both sides showed the depth of the inner deck is now .004” lower to match the gear height.

You can buy finer valve grinding compound than this. The plate is still quite uniform in flatness so I can do about two more pumps hopefully.

Smooth and flat with a few grooves. I will give those a polish with 600 grit

You can see a fine band where the pushed out lapping compound just “kissed” the outer wall. The depth of wear there is not measureable.

How the gears meet up with the deck now.

I flipped the plate over to the clean side, used 3M repositionable adhesive to glue some 600 grit sanding film onto the face and trimmed it closely. I spent maybe a minute polishing the inside of the body ledge.

Pinning the idler shaft.

IMPORTANT NOTE: As I noted earlier…if your shaft is loose in the plate…get another pump or plate.

There are probably several ways to do this but here are three:

1. The first one….my normal method can be done on a drill press. In fact it almost MUST be done on a drill press. The shaft is TOO HARD to drill accurately and safely through both pump body and shaft in one shot without a milling machine.

But on a drill press…first with a file, a square tipped carbide burr or an end-mill…put a flat spot on the outside boss of the idler shaft. It only needs to be about 1/4' in diameter. Just a flat spot for the drill. Center punch it. Use the correct drill for a either a 5/64” or 3/32” spring roll pin. USE A COBALT BIT.

Since these pins are just to keep the shaft from turning or moving…you do not need a solid pin or a big diameter pin. You can use a solid dowel pin if you want….but it is harder to remove if you ever need to. The spring roll pin stays in under spring tension and if you wan tyou can distort both ends for extra safety.

The object is NOT to try to drill a hole in the shaft. You drill a small clean hole through the aluminum and make the barest mark on the shaft itself. Them press or hammer the shaft out.

Once the shaft is out…complete the hole through the other side of the housing. Then…file a small flat spot on the shaft. Center punch it. Carefully drill through it with a cobalt bit. It is VERY hard.

Then draw a line on the end so you can align it with the hole and watch as you press it back in. When you get it close….tap with a mallet and brass drift until the hole lines up for the spring pin.

The nice thing about the spring pin is you can be out of alignment by a few thousandth and it will still go in and work.

2. the absolute easiest and best way is on a milling machine. You can drill through the center/side of the plate through the shaft at one time…and install a pin or a set screw.

3. The one I did on this one is somewhere in between. I ground a flat spot on the shaft, deburred, marked the shaft. Then I drilled a set screw hole in the side of the plate and pressed the shaft back in and installed the set screw with loctite.

I will get some pictures up of the shaft ground spot. Sorry.

This last part is optional but it helps to keep scoring down and oil the pump better. I have seen it done on other types of pumps.

So..find out which direction the pump turns…..and mark the leading edge of each gear for the direction it turns.
Use a Dremel # 425 rubberized 360 grit emery wheel to LIGHTLY polish a slight bevel only on the leading edges of each gear tooth. Do not go crazy here. It just forces a pressurized film of oil around to the face of the gear as it turns.

The last thing I will do to update this oil pump thread for posterity…is that since I am taking the gear to pump housing down to between 0.00” and about .0002”…I will test the the turning while at freezing by putting it in the freezer. I will also heat it up to about 200° to see what the endplay has expanded to. It should not be a problem either way as the gears will make clearance.

Ray

[furgo]

Keep up the good work, Ray. This is an excellent thread. Not only because of the attention to detail, but also the high quality pictures. Thanks so much for taking the time to document your build and sharing your knowledge.
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)

Decode your M-Plate

[raygreenwood]

[raygreenwood]

Update for 5-6-2018

The last bits and pieces for the oil pump build:

Some pictures I forgot yesterday:

IMPORTANT NOTE:

Some of these bits and pieces are very important…so in the dedicated oil pump thread I will put them in correct order. But for this thread it will be fine.

This is the notch in the idler shaft for the set screw to lock into.
I made it with a dremel tool on high speed-30k rpm and a green silicon carbide wheel. It tool about 2 minutes. Then I dressed it with a diamond needle file.

Use the green silicon carbide wheels. This shaft is hard emough that the pink grinding wheels will not touch it and the brown aluminum oxide wheels get too cut and cut too slow.

This is the set screw sitting in the notch.

Do not make a common mistake. You need to drill the initial hole through the side of the plate down to the shaft…just enough to mark the shaft. Tap the shaft out. Then drill the hole through into the shaft bore.

The mistake that is commonly made is leaving a little ring of un-drilled metal from the conical point at the bottom of the set screw bore.

Then tap the hole while the shaft is out. Use one of the gray dremel 426 wheels or points to deburr the hole exit inside of the shaft bore after tapping.

IMPORTANT NOTE: as in the picture above, make sure the notch is slightly wider than the set screw so that the shoulders of the notch do not contact the thread of the set screw keeping it from making full contact with the shaft.

Why did I use an 8mm X 1.25 set screw instead of 6mm?

Because there is plenty of room and the 8mm has more thread area and more contact point area to lock with. This means that I can make the set screw tighter to bite into the shaft without over stressing the threads in the aluminum. Yes…its overkill...

Earlier I noted I was not going to lap this area.
During a mock-up with the reduced gear to plate dimensions inside…I noted a lot more drag than I wanted so I decided to lap this area just to smooth it a little.

I used another scrap of Mic-6 plate with a slightly oversized hole drill in it for the shaft to go through.
Though I do not recommend lapping seriously in a circular fashion because of the risk of making a surface conical….just lapping to smooth is not a big deal. Maybe 30 revolutions in a minute is all this took

And I finished it up with some 600 grit sanding film spray glued to the disc

You can see where the yellow arrows are pointing that I have polished and beveled the leading edges in the direction the gear turns to scoop an oil film between the face and the plate and bore.
The gritty look is just lapping compound.

So after cleaning its time for partial assembly and mock up to see what else may need clearance. The first thing to do is to re-install the 6mm studs.

VERY IMPORTANT:

You will screw this up slightly if you do not make make preparations. Make a check list. It will save you from pulling these in and out.

1. MOST IMPORTANT: at a “glance” all four of the oil pump studs look to be the same length. THEY ARE NOT!

The stud that goes into the hole where the plate alignment bushing is ….is about 2.5mm longer.
It is longer because the threaded hole is deeper to compensate for the thread loss due to the counter bore. So…sort out your studs, find the long one for the counter-bored hole and do that one first.

NOTE: I am using Loctite on these studs. Locktite dries fast. Even though it dries...in air…drying in air does not CURE it and cause it to have useful strength…so have your ducks in a row to get thes parts together quickly. So……..

2. As you work in order….BEFORE applying Loctite to the threads in the bore (not to the stud)…go ahead and tightly “double nut” the stud you are about to install FIRST.

3. Then with a wooden or plastic pic or rod…..put a small amount of Locktite in the threads DOWN in the bore about 2-3 threads away from the outside of the thread bore. We are trying to keep Loctite off of the inner deck mating surfaces.

4. IMPORTANT NOTE: When you install each stud…it will bottom out.

When it does…back it out ONE complete turn. Mark the outer tip of the 6mm stud with a Sharpy marker so you can see it turn. Let the loctite cure for a minute or two and remove the two nuts.

Assemble the pump without the gears and tighten the nuts. Then look carefully at the inlet and outlet ports.
Because you lapped the inner deck….the plate will sit slightly farther down into the pump body...and a bit bit of the plate will overlap the inlet and outlet ports.
Lapping out .004” on the inner deck is not much..…but it actually makes quite a difference on a curved orifice. You can see the overhang at the yellow arrow above. Clearance this away with an abrasive polishing tip.

Also you need to clearance the outer housing…sorry its out of the picture…but the arrow at 6:00 is pointing to it.

Here you can see what needs to be removed.

This is the best tool I have found. This is a rubber polishing point impregnated with 600-ish grit abrasive.

This is Dremel part # 462. Its so soft that about 1 minute of polishing (about all this takes) will literally destroy the point.

You can also get them in pointed cones and square cones. These are the blue ones. They make them in several abrasive grits that are color coded.

IMPORTANT NOTE/QUESTION: Why would clearancing this small amount of “flashing” make a difference?

ANSWER: It does not really make much of a difference at all…in FLOW VOLUME…however it makes BIG difference in TURBULENCE at the port.

THAT can make a big difference in flow.

The whole point of this is to tighten the pump back up for efficiency.
This is just about it for the oil pump except for oiling, assembly and turning to pre-clearance the inner plate…remember that this is set for near “0” internal clearance right now.

Also I will not be doing final assembly until I can put the pump in each case half and check its alignment to the port in the engine case. I will be clearancing that area as well.
Ray

[Clatter]

[raygreenwood]

A small update:

On the oil pump….I found a better set of gears in my stash and got the gear lash down to .003”. The pump is slightly tight so I will be running it in to make proper clearance but it is essentially done.

These pictures are from about 3-4 weeks ago and I am running behind getting them up.
The crank was put into the case to measure and plasti-gauge the bearings. Those will be put up this weekend. I do not have them with me on my drive.

Here is the cam gear train measuring/checking:

We are checking three items:

1. Axial runout:

There is no separate axial runout for the cam gear itself…but it “should” be the same or less than the runout spec listed for the camshaft itself for the same reasons.
If the camshaft runout as measured on the center bearing of the cam or the radial play as measured at the gear flange end of the camshaft are excessive, you get excessive axial play at the gear mesh.

So….once the cam itself is measured and it passes, the gear must be checked separately to make sure its recess for the flange is machined correctly. The shaft runout is .002” max and the radial (which takes the bearing preload into account) is .00078” to .00196”…so a max axial play at the cam gear should be .002”

2. Radial runout/concentricity:

There is no spec for this one either but for all of the same reasons with camshaft axial play the maximum spec should not be above .002” to .003”. It can be slightly higher for radial play if the axial runout is also small because the radial runout is not an angular change.

3. Backlash:

The factory spec for backlash is .000” to .0002”.

The Crankshaft gears:

To start out, the owner of this engine provided me with 2 gears. One has slight damage and the other one is just fine. I am going to detail the slight damage to the gear I did not use and cleaning up the damage. This will be a great spare gear for him.

The warning here is that you should inspect and correct minor type 4 crank timing gear damage whenever you can.
Try to save these gears at all cost. Outside of rust or foreign object damage, they do not wear out….AND…they are also not made by anyone new and have not been for a while. The only NEW gears you can get are straight cut gears. Conserve parts whenever you can. There are a very few NOS available but that is not a sure thing.

The clean gear:

This has not been cleaned up yet but not the crisp edges and carefully machine chamfered edges. This is the crank side of the gear as you can tell by the large chamfer on the ID.

Note the dinged/bent teeth on the inner side. This does not appear to be from difficult removal and I will point out why in a moment. For one…virtually every tooth has some damage.

It’s hard to see from this picture but the whole backside appears to be burnished. This combination of features is what happens when something falls into the case and dings and rubs on the backside of the gear.

This gear also had a little rust from probably sitting inside an engine that got some water in it.

Here it is after cleaning up and polishing off the dinged edges. It’s actually a good serviceable gear. The yellow line in the picture below shows where the aluminum cam gear runs on it and why polishing off the dinged ears is necessary

The yellow arrow points to the polished spot. You can see a little rust pitting here but it’s not a problem unless you can read low spots during a backlash test.

You can see how well the rest of the gear cleaned up. This was done with oxalic acid.

Axial gear play measuring:

The dial indicator is set up on the smooth edge of the face away from the gear teeth and 0’d.

When turning the crank to measure this…just like shaft runout…you need to put pressure on the center bearing of the camshaft…maybe 5-7 pounds to keep any of the minor amount of shaft runout you might have from spoiling the reading.

NOTE: I also measured runout of the gear while the case was together and the bearing crush was clamping the camshaft. I am doing this just to confirm both measurements.

The radial runout was .0022”. This is .0002” more than you want…but after deburring the gear edge with a green scotch brite I got that down to .0018”….and this also takes into account the small amount of shaft runout I got when measuring the camshaft itself.
This gear is quite straight axially.

Cam gear radial runout/concentricity:

This is the set up for measuring concentricity. It’s a pain in the ass. I got better readings after doing this two times by using my wide polished probe point like I use for backlash.

The gist is that you need to start checking….and get the probe point on the same spot on each gear tooth in the first place….and find the lowest or highest tooth.
Then mark it and check all of them or at least every other one, all the way around. After writing them down and comparing you can see if it’s out of round.
Tedious. I found it was right at .0017”. Pretty damn good considering there is also some suspect probe placement. It took three repeats to make sure I was getting it right.

Gear backlash:

The gear backlash was .0015”…which is pretty damn good for a -3 gear. This makes me happy because I have been worried about the fact that the cam houses…and everyone are only selling -3 gears.
They must know something.
I think a good portion of what people are finding when their gear lash is really excessive….is a combination of gear lash under and up to .002” and some of the other runout specs combined. As noted….when measuring any of this…you need to secure the cam at its center bearing.

I actually use a piece of oiled paper towel and a bungee cord when I need both hands. I will post a picture of that later.

Extra stuff:
So a few weeks back, removing the needle bearing from the crank…was the first time in ages that my “grease pump” trick failed me. And since I did not want to be beating on this crank….I stopped an made a pilot bearing removal tool.

This bearing was not rusted…just damn tight.

I made this from a piece of cheap 7/16” rod stock, a ¼-20 bolt, set screw, some tapping and drilling and grinding on the bench grinder and with the angle grinder.
I think I have $2 and about 1.5 hours in it.

It pulled the bearing in two light pops from my home made 5 lb slide hammer I made for removing galley plugs..

I will make a how to with dimension for it at some point.
Next up will be the pictures from the plasti-gauge and crank bearing measurements. That’s all done I just need to update.

A few more bits and pieces and some word on heads and rods….and some test fitting of oil pickup and distributor drive….pull testing of ring tension….and we will start the case assembly.
Ray

[Lars S]

Thanks again Ray!
That bearing puller looks neat...have been fighting to get that bearing out many times! Did not know there was room for small claws behind it...nice!


//Lars S
_________________
Porsche 914 -72, Bahia Red daily driver
VW411 2-d -70, White, sold
VW412 4-d, -73, Gold Metallic, daily driver
Suzuki T500, -69, Candy Gold, sold
Suzuki K50, -77, Black, daily driver
BMW R69S -69, White, sold
Husqvarna 118cc, -47, Black, Sold

[raygreenwood]

Update for 8-9-2018.

Sorry its been off and on busy. It goes in good sized spurts. Not far off and it will go faster.

This is a small update...just wanted to show a tool I made for working on this engine build and my engine build later this year.

The rods should be back from the shop soon and then the case, crank, rods and bearings will get their last mock up. Then pistons and cylinders and then down to the heads and outside components.

The rod bolts while in pretty damn good shape....at this late stage in life and good quality engine cases and parts not getting any easier to find if you have a catastrophic accident with a connecting rod.....its far smarter unless you are using new rods with new bolts.....to just replace the rod bolts when rebuilding the rods.

Sourcing actual type 4 rod bolts is not easy. And...then wondering about quality.
Considering the $$$$ that are going into this engine already...its not worth cutting corners and wondering.

So I recommended buying some ARP ...type 4 specific connecting rod bolts.

Yep...they are not cheap....but far cheaper than snapping a rod bolt.

These run from $130-$145 a set. It comes and goes in price and sometimes you can find an Ebay deal in the $99 range if you have time to wait.

There is not one fault I can find with ARP products....and their rod bolts are superb.

BUT....you really MUST use a rod bolt stretch gauge to install them properly.

The gist is that you apply a specific lubricant that comes with the bolts, measure their starting length, torque them specifically and then measure the length and re-torque until they stretch a specific amount.

In the past when I have installed these...I have used both a 1/10,000" micrometer...which works but is very tedious and triples the amount of time this takes to actually get accurate readings...or I have borrowed a bolt stretch gauge.

The basic gauges are not that expensive. They run from about $50 to $70 at Summit and Jegs....or to about $250 for a gauge from ARP.

https://www.summitracing.com/parts/sum-900015?seid...G0EALw_wcB

https://www.summitracing.com/parts/arp-100-9941?se...tjEALw_wcB

Those costs are directly reflecting the cost and quality of the dial indicator. The Summit and Jegs basic gauges use a 0.001" dial gauge...probably Chinese...but good enough. And the ARP gauge uses a 0.0005" gauge...better for serious work.

If you look closely at the Summit branded gauge and the ARP gauge....they are the same tool frame...simply with a different/better gauge. That gauge is probably only $50 in the price difference....and the ARP name is probably the rest of it

So....I decided to make a rod bolt stretch gauge. I used my existing Starrett dial indicator gauge...which is 0.0001" tolerance with jeweled bearings and a 0.200" range....and chunk of 1/2" mild steel plate I had laying around, two drill bots and one tap...and a good amount of angle grinder, drill press and bench grinder.

I spent about 1.5 hours making it. The two 3mm screws cost me $1.10, the plate was probably worth $1, the angle grinder cutoff wheel was about $2....so maybe $4.50 and some spare time.

Not bad.....I have gauge that is more accurate even than the ARP gauge and I got it done for under $5

You will notice below...that ARP machines dimples in each end of their bolts specifically to be able to use a bolt stretch gauge.

A bolt in the gauge. In operation the bolts will be on the rod. I will be checking and correcting clearance of the gauge when the bolt is on the rod later today.

Its interesting. At some point lately...at least for rod bolts made for Porsche...maybe all of them...ARP changed their packaging. I am sure this goes over much better...actually listing a part for Porsche....will drive sales!

The blue package on the left is the new one. The one on the right is my set from about 1999....which are finally going to get used this year!

I will post the pictures and method for checking bolt stretch next week.
Ray

[raygreenwood]

Update for 9-7-2018

I just got the connecting rods back from the machine shop. It’s a pretty good machine shop! Almost strictly American cars and racing equipment but great tools, chassis dyno and very busy. Nice people, decent costs and they take instruction well.

The big end journal bores…while they originally were not that bad….they are all now round within about .0001”. So if you look back to the first page and note the rod “map”…all measurements are with .0001” to .00015”. They look very nice as does the deburr work on the sides.

The big end side measurements after deburring:
Rod # 360: 1.0079”

Rod # 081: 1.0078"

Rod # 602: 1.0078"

Rod # 895: 1.0057”

This leaves all of the rod side clearances right around mid 3/4 range of max tolerance. Which is just fine. Nice and smooth t00.

They also installed and set with a stretch gauge, the ARP rod bolts.


The small ends…the pin bushings…from rod to rod…are very consistent. All four are dead on 0.9452”.

BUT….That’s not perfect tolerance wise…and this set of piston pins are about .0001” smaller than normal. I noted this when I picked the rods up. The pin fit is slightly loose….but was good enough to walk out of there with. I have had this problem with more than one “domestic race” shop when talking tolerances and “push fit” for full floating wrist pins.

As I noted….the bushings that were in these rods were worn about .0001” to .0002” oversized to the pins. By that I meant…to where the tolerance of pin bushing to pin…..needs to be MAXIMUM. So the pin bushings that were replaced….were getting right close to .0009” to .001”….which are still…technically…in tolerance.

More on this “tolerance” in a minute.

So right now…these NEW bushings look like this:
Pin bushing bores: 0.9451” to 0.9452”
Pins: 0.9445”

So the tolerances are: 0.0006” to 0.0007”

Better? Yes. In spec?...yes…..but…not what most are used to. The pins fits smooth as glass and are a dead fit with no play. But they slide out under their own weight in about 1.5 to 2 seconds (lightly oiled).

In reality what most people consider a normal tight push fit…where a little too much hand warming can make a very tight fit…. is right at and below the minimum factory tolerance limit of 0.0004”.

A range of 0.00035” to 0.00045”
Does a tolerance of 0.0007” average mean that these are too loose? No.

And…by the way…the top end allowable factory tolerance (0.0016”) should be IGNORED. No wrist pins should ever be that loose!

I have built many of these engines with 0.0006” to 0.0008” pin fit…and never had an issue….but I would like them slightly tighter.

It’s not an issue because I have several sets of pins. I have a set of KS pins either new or very low miles that are pristine…with an OD of 0.9448”….that bring the average tolerance down on these rod bushings to 0.0005” to 0.0006”…which is noticeably tighter and increases the “slide out” time of the pins under their own weight to about 2.5 to 3.0 seconds.

Also interesting is that the Kolbenschmidt pins are slightly larger OD and slightly lighter.

So…back to the tolerances. I HATE the available books on type 4 and Porsche 914 engines. The specs are all over the place!...and TYPOS too!

Examples:

From the Haynes 914 book:
0.02mm to 0.04mm (0.0008” to 0.0016”)

Hayne 411/412 book:
0.01mm to 0.04mm (0.0004” to 0.0016”)
And the 411/412 book…has a TYPO in that inches number!...Listing 0.004” instead of 0.0004”

Haynes Bus book:
0.01mm to 0.04mm (0.0004” to 0.0016”)

Porsche 914 tech specs book:
0.02mm to 0.03mm with a wear limit of 0.04” (0.0008” to 0.0012 with a wear limit to 0.0016”). This is properly stated. The wear limit should be the maximum number stated everywhere.

Without guesswork book:
0.01mm to 0.03mm (0.0004” to 0.0012”)…with a wear limit of 0.04” (0.0016”)

So really…. I would say the REAL…. FUNCTIONAL…. tolerance range should be between 0.0004” to 0.001” MAX!

Operating tolerances anywhere between 0.0004 and 0.0008” should be fine. Perfect tolerance being right between .0004” to right at 0.0005”…with a max of 0.0006”

I make that last statement….because…….if I left these bushings and pins the way they are…roughly .0002” more loose than I consider perfect…would it be a problem once they are in the engine and the engine warms up?

Well….while I have never had a problem running them this way.…I decided to put a rod and pin in the oven at 350° F to see.

This increased the stiffness of the pin fit….I would estimate…by about 20-25%. The pin takes about 3 full seconds to slide out under its own weight. With the 0.0001” larger KS pins…it has to be pushed out with very light finger pressure.

I think they will be fine either way. I will decide on whether to use the slightly larger pin set at final assembly time.
Ray

[Alan Brase]

All pretty nice stuff, Ray.
One thing I wonder about is center to center rod length. I know one of the shops I went to years ago could bore small end of rods, install bushings then bore the bushings keeping the rod length uniform. Perhaps Tobin- Arp machine? (this comes working on small block Chevies with original pressed pin in the rods. SOP was to hone the rod end bigger and just have steel to steel floating fit. Brass/ bronze bushings are usually a better idea and the old way it was done.)
I've honed (resized with Sunnen precision hone) quite a few rods back a half century ago. did they cut both the rod and the cap or just the cap before resizing? cutting the rod will make the length shorter. Just one more thing the engine builder can/ needs to control.
Al
_________________
Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home

[raygreenwood]

[Busstom]

Impressive. This should be a Type IV Engine Rebuild sticky for extremists, a go-to reference of sorts (I mean that in a sincere manner ).

[raygreenwood]

Thank you!

Now that the damn time sucking holidays are over.... ....I hope to have the update in maybe by early next week.

I have head baseline estimates in and should have deck measured off the mocked up cylinders by Friday. After I get a final on what needs to be done to the chambers....if anything....to set compression....its time to strip and clean the case and parts again. Hopefully I can do final assembly out the the heads by the end of January. Basically almost buttoned up.
I will mock the heads up on the engine and furn everything around and make sure everything is sealed properly.....then pull the heads off and bag everytying until a little warmer weather to do final oiling and assembly. I want to make sure it does not,sit very long before firing up. Ray

[raygreenwood]

Update for February 18th 2019:

Sorry this is taking so long. Since moving in October…the holidays and then weeks on the road…then catching up.

Sorry…as usual this will be long. I try to explain some of the different ways I do things because they may help other people.

The cylinder stud prep and cleaning:

So to go off on a long tangent here….

Some would call it over kill…..some even stupid….but more than once in the past 10 years I have broken a cylinder stud trying to remove it. Then…now in a pinch…and always at the wrong time…I could not quickly locate a spare.

So back in 2009 I think I bought most of a whole set from Jake Raby’s store as spares. So just like anything else that does not grow on trees and is no longer made (yes I could order studs from ARP….but would have to re-tap the case probably…plus the $$$)…I have learned to invest a bit more in time or effort in parts like this to insure longevity.

These are class 12.9 studs....at least! Probably heat treated. Very strong and elastic yes. But with the handful I have broken over the years…I found that the main killer ….was external rust. They broke/fractured where they were pitted.

So I went through this stack of studs and some of my spares. I cleaned them carefully with Scotch bright (medium and fine) spinning them in the drill press. Use no heavy abrasives…you do not want to scratch/groove these.

Then I heated them after masking to about 175°F. I did this to first dry them well and to speed drying and make sure the sure the paint was as hard as possible. I spun them while painting them.

NOTE: Treat them just like CV axles. Both can fracture at groove and pit points. Then went up the length with a stainless Dremel brush. Do not use the carbon steel brushes. The carbon steel will remove metal.

To prevent rust…and I have used this product on CV/drive shafts and at least two sets of cylinder studs with great results….I sprayed them with a cold galvanizing compound.

To those who do not know what this stuff is and what cold galvanizing means….

First…does it work?

Yes…it does. But understand how it works. It’s an enamel that is very high in zinc (48% by weight typically). It works by getting the parts as clean as you can and spraying it on thick…two coats. That volume of zinc means that roughly every other particle of the paint in contact with the metal is zinc. So it does a better than fair job at being a sacrificial anode.

But not being a full seamless electrolytic coat of zinc with every particle in contact being zinc... like zinc plating….it needs to be sealed from oxygen as long as possible. That’s the paint resin’s job. The paint base works similar to chromate on top of zinc plating.

Zinc begins sacrificially converting to zinc oxide almost the instant you apply it whether it’s in paint or plating when it hits oxygen…. creating a white powdery dust called white rust. It’s supposed to do this. As long as the zinc is turning to white dust....oxidizing to zinc oxide… there will be no ferrous metal rust…even in areas very close to zinc that are not plated.

Once the zinc is fully consumed to a powdery white residue…which might be decades….then the steel/iron rust starts.
The colored chromate sealers you see on zinc…are simply a surface oxygen sealer used to delay the start of zinc oxidizing as long as possible. It can almost double the life of zinc plating in corrosive environments. The paint portion of this cold galvanizing compound has the same function. It’s a sealer.

2nd….is it actually "galvanizing"?

At first...years ago... I scoffed at the use of the term “galvanizing” with regard to cold galvanizing…and thought NO WAY! …until I did the research and found that “technically”…..because any cathodic protection by sacrificial anode (zinc aluminum or magnesium)…is a galvanic reaction….is called galvanizing....whether its plating, zinc paints or actual large crystal hot galvanizing ....it is truly a form of galvanizing.

Cold galvanizing should be weaker galvanically than hot dip galvanizing or straight zinc plating because it has lower zinc content… right?...but….wait ….not so fast….maybe not actually. It turns out it’s also partially about the sealing and metal contact area. More on this in a minute.

3rd….then wouldn’t it be better just to zinc plate or galvanize it?

That’s the issue....you can’t easily zinc PLATE these types of parts …or the factory likely would have!

Galvanizing and the electrolyte that carries the zinc is not always ideal on heat treated or stressed parts….but it can be done. The bigger problem is that with classic galvanizing like you see on sheet metal…the zinc’s large crystalline form has issues much over 400° F. It breaks down the structure.

So no not hot dip galvanizing.

The zinc electroplate has some of this issues as well due to the chemistry on tempered surfaces.…..and you cannot use Electroless zinc because just like with springs…or anything tempered…putting them in an acid bath destroys the surface tension.

Typically parts like this are phosphate coated with a non-oxidizing acid or caustic and then oil pickled….or painted….or powder coated….meaning just sealed for as long as possible. Black phosphate is only good for a while. And...Zinc phosphate like that used on guns sloughs off at about 400F because the heats shrinks the crystals.

In the realm of keeping steel/iron from rusting…these are the best methods in order:

Zinc-Nickle plating (ungodly expensive but fabulous)

Zinc plating with a chromate sealer (when you can)

Zinc rich epoxy coating…very cool! Expensive-esque.
Must be abrasive grit blasted to activate surface which disqualifies it for these parts….but with about 70+% zinc, instantly highly sealed and nearly as good anodic protection as zinc….but with a far tougher epoxy surface sealing and can outlast zinc plating in harsh environments.....its BETTER in some places than zinc plating.
A plated part that is then IMMEDIATELY painted can have this same effect/strength.

Galvanizing…..Cold galvanizing…is about equal if cold galvanizing is applied properly where hot dip galvanizing is not used in hot environments.

Painting/powder coating/phosphate and oil pickling...way down the no-rust food chain.

Anyway…that’s why the cylinder studs are gray. Back to the engine at hand!


NOTE: you will notice items in the pictures: There is no distributor drive or spacer on the crank yet…this is still in the mocking up stages…and no oil pickup yet.

CC’ing piston dishes:

I CC’d these with a calibrated syringe (that just means it’s for actual medical use and not a dime store Chinese syringe…so it has decent certification).
I hate using my burette unless I have a lot to do that needs it. I use a syringe mostly…a good syringe.

I should go through how to accurately read a syringe. It can really help those who cannot afford a burette just for occasional use …but once I explain (and there are MANY videos and article for this on line so don’t just take it from me)….you will go…”oh yeah….I watched the nurse/doctor one time and wondered why they did all of these things”

1. The syringe is read pointing straight up.

3. The top mark you see here is EXACTLY where the liquid should stop…not filling up the area in the conical top. It’s very difficult to get it exactly on the line…so from above…looking like this is normal.

So…for example… if you want 20 cc…you pull in about 23-25 cc’s. Hold the syringe straight upright and level….and pull the plunger back to pull in an air bubble until the liquid hits the top line.

Then read the bottom line on the plunger head. If you have too much…push the plunger up to expel some liquid and then pull it back in again so the liquid is at the top mark to read the level again.

What you are seeing the nurse/doctor do when they tilt the drug bottle over sideways and push the plunger to expel excess liquid back into the drug vial….what this is doing…is allowing the exact size “reading” bubble that is up in that conical top area…. to float back to the plunger so you do not expel any of it.

This is so that after you expel liquid and then tilt the syringe back upright again…the same amount of air is back in that conical top…placing the upper liquid level right back at that top line so it’s ready to instantly read without having to adjust the amount of air again. When you tilt the syringe back vertical and that already properly sized air bubble floats back to the top….you can get an exact reading again without tinkering.

It’s very hard to get an exact line on the top line without some surface tension creep into the conical area. This is normal and is about 1/50th of a CC or less.

This is my Plexiglas CC plate. It actually my 90mm cylinder CC plate:

That white plastic plate is a .015” thick polypropylene insert used simulate taking .015” out of a 1.7L combustion chamber when CC’ing. You take a round piece of flexible plastic. Put black Sharpie around the edge of the chamber…drop in the plastic and burnish it down. It will now have the edge shape of the chamber dish.

Then glue it to the Plexiglas disc….and with an Exacto knife…trim away the edge and peel it off. Now you have a flat plate with a .015” thick shim that fills .015” of the dish so you can see the actual effect of fly cutting on head CC’s.

Silicone grease

So at first the piston dishes were all 9.5cc on the money.

But….I made a mistake. I got 9.5cc. Did it twice on each piston. I was having trouble on #3…getting the water to flow in an even stream without forming bubbles and blocking the hole….when I realized…I forgot to break the surface tension of the water…by adding 50% IPA. DOH!

On #4…with 50/50 water alcohol….I got a dead on 8.5cc. Re-did all of them…..8.5cc. Yes….the surface tension makes that much difference in that thin area right near the edge of the dish.

The pistons:

Very nice 93mm Kolbenschmidt (NOS from quite a while ago)!

Marking the pistons right over the pins on each side so I can target where to put the depth mic:

Cylinder studs installed in case:

Rod bearings installed in rods and lubed with assembly lube. I like the Moly-graphite assembly lube.

Rods mounted on crank. I did not torque them 100%. These are ARP bolts so I will check with a stretch gauge again when fully torqueing them down on final assembly. They are at about ¾ torque right now.

By the way…the rod and crank machine work so far seems excellent! These rods take about 2.5-3.0 seconds to go from the 9:00 position to the 6:00 position under their own weight….and of course the measurements are spot on.

Measuring rod to crank cheek clearance (side clearance):

The books show to measure at the narrow area at the top of the cap. The highest amount of wear is here and at the opposite end so it will be widest here. I measure this area and on the sides.

Here are the rod measurements before installing and the side play measurements on each crank throw. Since there is small variation in the rods and some variation on each crank throw…I will mix and match later to get the best fit I can in each spot.

For now I simply numbered the rods 1-4 with no real location planned yet to see what each rod gives.

Below is the rod big end width measurement on the left and the journal per each cylinder with a rod on it with side clearance noted. The wider measurement of each two is at the top thin area at the end of the rod cap.

So for instance….from that chart…moving rod #4 to journal #2….in place of rod #1 will give a 0.001” reduction in side clearance to that journal. While all of these are close to the top of the tolerance range….they are nowhere near the wear limit and its pretty much par for the course in used parts.

While they will lose a little oil pressure….keeping the rod bearings tight near the bottom of the normal tolerance range will offset that decently.

Assembling the pins on rods and pistons…no clips and no rings:

First thing…note where the arrows to point to flywheel are stamped…and then mark them with big visible arrows.

Button up and torque the case six main bolts.

Then with a hard plastic mallet (if needed) I tap each pin into a piston so it’s just protruding enough to register on the bushing.
BUT FIRST…plan the directions you will need to have the pin installed in the piston

Mount the piston on the rod. This is #1 I am starting with.

I made a nice little pin pusher tool so I am not whacking around on things. It’s a piece (several lengths actually) of 5/16” threaded rod, some UHMW or nylon bushings to center the rod in the piston pin, a thick disc of any slick plastic (I used UHMW) on the pull side and a disc of UHMW smaller than the pin on the push side…3 nuts and two steel washers.

Here it is working on #1 pin:

Here is the tool position on #4:

Piston #3 was a little trickier. I used the shorter threaded rod and the locknut combo was right up against the case but it worked fine.

The cylinders were oiled and installed on the 3 and 4 case half. I carefully put each cylinder on each set of studs…no sealer and no shims.

One quick observation makes me happy! Notice how tight the deck is. I was hoping and wanting it to be too tight so I can shim to what I need and have a nice tight deck!

Locking cylinders down:

I have a little kit box with eight 3.625” pieces of thick wall PVC pipe and eight pieces of 1.625” pipe, 16 thick flat washers and 16 10mm x 1.50 nuts. All clean and just for this so I am not piddling around with hardware that may be dirty.
I find they get plenty tight enough for this step with no gaskets or sealer and less risk to cracking a fin with steel tubes.

I have both a depth mic and a dial depth indicator. To start off I like using this gauge.

And….this is where the problem reared its head. Nothing I can’t fix. In fact it may not be anything that needs “fixing”…yet.

These are listed outside of cylinder first and inside close to adjacent cylinder second:

Deck piston #1: 0.024” and 0.025”

Deck piston #2 0.023” and 0.024”

Deck piston #3 0.017” and 0.016”

Deck piston #4 0.017” and 0.017”

So….betting that with a bit of tightening and cleaning I can get #1 and #2 to read within a clean .001” of each other….call it .024”….the 3 and 4 side is a consistent 0.017”…meaning a hard .007” difference from left to right.

This is pretty much indicative of the 1 and 2 side:

This is pretty much indicative of the 3 and 4 side:

Possible causes:

1. I doubt that with just grabbing rods, pistons or cylinders randomly…that I could get two on the same side that are nearly exactly the same amount off.
Of course…I checked the rods with a down pin first on the big end on a granite plate…and checked to both sides of the little end to make sure the stroke length was ground concentric. They are very close….with .001”

2. Of course…the pin height could of be off on the pistons….doubtful two would be out exactly the same and wind up on the same side…but stranger things have happened so I will check that too.

3. The case has never been decked….but measured flat between spigots and the same depth to the granite.

4. The cylinders were measured base mount to seating area….less than half a thousandth variation.

It’s possible something….flashing…may be on the case spigots or some dirt got there. Will check.

NOTE: the 3 and 4 cylinders show a high spot on the inside sides of each cylinder with a machine rule across them. I am thinking something is clamped between the cylinders and cases.
By the way the crank with pistons and cylinders spins like glass a full 360° in each direction

The two most possible causes….one I seriously doubt:

A. Somehow two rod journals were ground offset?....doubtful….but I will pull the rods and mic the crank throw from the spigot.

B. The crank centerline is off in the case? They are rarely exactly perfect…but I can check each case half with that very dial depth gauge I showed previously. It’s why I bought it.

As noted…..betting something is propping up the cylinders or it simply came from the factory with 0.007” crank offset difference.
No big deal. I will fix it.

So we are here for the moment:

Next stop…head shop with the final measurements so they can fly-cut correctly....if need be
At this rate….since these heads had the step in them…which they should not…if I can get the 3 and 4 side sorted out to the same .024” as the 1 and 2 side….I will have the 0.035” step removed…and depending on chamber CC’s and compression…simply add a .015” shim to the bases….and end up with .039” deck…which I have no fear of because the pistons have dishes and that’s a nice deck.

The valves:
These valves came in about 10 days ago. Very nice….Manley Race master valves. Stainless steel one piece, stellite tips, heavy chromed stems, swirl polished heads. Not actually that expensive. I think they were about $95 per set of 4 intake and exhaust with shipping. These are listed as the standard Porsche 914 1.8 and 2.0 valves 42 x 36.

Nice valves!
More to come!
Ray

[Busstom]

Beauty...Looking forward to hearing about the deck height culprit, and the next installment. Don't be making us wait so long!

[raygreenwood]

The deck height difference........

So with a little tweaking....mainly just checking cylinder base to case cleanliness and retorqe with a slightly different pattern to the six case bolts ....I was able to get the right side (1 and 2) to pretty equal 0.024" to 0.0245".....call it even....kt will go up and down by .001-ish in this stage when measuring in line with the pins and crank because there is no flywheel (flex plate).....and at the moment....no flywheel shims.

So the slight fore and aft movement of the crank can produce the +/- movement by as much as .002". You just have to know its there when measuring.

So I am happy with seeing how equal the 1 and 2 cylinder decks are.

And.....in that same respect.....the 3 and 4 cylinders are also within that same .001" ....I got rid of that .016" measurement......and the tolerance in line with the pin fore and aft on each piston.....so I am happy.....ish.....with those as well....except that......they still are 0.017" for deck. That is .007" from side to side.

What I know it is 100% NOT:

1. Not the pistons. I got a good comparative measurement on pin height to piston top on all four pistons. Dead on.

2. Cylinders. I swapped them around twice side to side and diagonal and remeasured the decks.....no change.

I will be removing pistons and rods again.....and rechecking the rods from top of big end to bottom of little end. I checked them when they came back from the machine shop....but things were crazy about that time so anything is possible.

I need to double check to make sure that the big end was not offset down or up and the little end moved to match......not explaining that right.....but hopefully I can show you. The shop who did the rods was an excellent racing machine shop and they took great care. I highly doubt its the rods.

Things I have found:

Its very hard to measure....but just measuring between the rear seal bore wall and the snout of the crank......it is very slightly off toward #3 and 4.
I am pretty damn sure that the case....which has never been align bored....came from the factory with the crank centerlin...... 0.007"....off-center.

It would not be the first one.

When the case is back apart....I will "0" my Baker dial depth gauge in each bearing bore on the 1 and 4 side and then transfer the gauge to its opposite side bore half on the 3 and 4 side. That will tell the tale.

The other minor problem is that when you are looking at the 3 and 4 cylinders dead on....there is a high spot....a hump.....of about .003" at the 3 oclock position on the #3 snd at the 9 oclock powition on #4. It makes the machine rule high center in that spot. In other words....exact opposite of sunken spigots.

I have seen that before too. Its not in the the crank main journal bore.....that measured excellent. It may have been eons of heat cycling with the center two case bolts loose.....or slightly overheated case.....could be anything. I did not see it when checking for sunken spigots. It happens when the case it buttoned up. I will also check for any strangeness or oversize to the center main bearing.

Not hard to fix either way.

In the end.....if its going to be .007" offset.....it will just be a different shim pack side to side to get the same deck and stroke.

Pictures to come.
Ray

[raygreenwood]

UPDATE 2-23-2019

So…I took the pistons and cylinders off and measured a few things. I found the missing 0.007” from the deck height on the 3 and 4 side…right where I thought it would be. The crank bore was of-center by .007” from the factory.

And…it’s also off-center not just in X and Y…but in “Ө”…meaning if you are looking at the engine from the top of the case…cylinders going outward side to side left and right.

It is off about 0.001” skewed…from one end of the crank to the other. Its really common…and insignificant.

In other words….looking from the top….the flywheel end of the crank is about .001” closer to #3 and the opposite end is the same amount closer to #2.
Using my crude but effective piston pin puller/pusher tool to remove the pistons.
Actually the garage temp wear nearly perfect today and I could simply push the pins in with some effort….but getting them out is easier with this.

So here is the 3 and 4 side of the case…the one with the 0.017” deck height… with the dial depth gauge centered in the center main bearing bore.

And after the gauge is “0”…I switched to the 1 and 2 side center main bore…..and….there is the 0.007”. Its .007” shallower than the 3 and 4 side.

And here is the flywheel end main bearing bore on the 1 and 2 side….0.006” more shallow. The crank is at a skew angle by about .001”

NOTE: I buy most of my measuring tools new. I’m not rich so I save up or trade work for tools. But I have bought a few “ebay” tools.
Most are never as well kept, clean or accurate as advertised. I prefer pawn shop tools where I can check the action.

But…this Baker dial depth gauge set was worth every penny of the $45 I spent on it on Ebay. I bought it just for this type of work…doing main bearing saddles. It has paid for itself many times.

This is the 1 and 2 side of the case and how much more shallow the bores are.

With a granite plate beneath the spigots they are all level within that 0.001” we see end to end with the crank skew.

I have a diamond lapping plate I may surface the case openings with to get it dead even. It’s just not enough to make it worth decking the case when it’s this close. It’s flat and parallel.

I will have to see what I can get for shims. It may be worthwhile to lap the 3 and 4 side down to an even .015” deck so shims are easier to get spot on.

More to come! Ray

[RalphWiggam]

Nice man. Gives me flash backs to when my deck heights were not making sense.

[raygreenwood]

4-22-2019

A short update:

I must apologize this is taking so long. Lots of in and out of town, moving…winter….damn!

I have had these heads over a year and myself and the busy machine shop personnel have been playing “in-town/out of town/missed the window” tag.
We finally all arrived in the same place on Saturday.

So….the cylinder heads.

I do not have many pictures just yet. More to come.

These heads were rebuilt maybe a decade ago and never used. Just shrink wrapped and waiting.
We ALL know how that goes…..projects get delayed!

They were rebuilt by …let’s just say one of the top type 4 shops out there. And I will say…overall they look excellent…quality and work was excellent. However….there were a few errors….that have mainly to do with THIS APPLICATION.

The VW 412 1.9L engine is essentially…identical…. in every way to the 1.8L Porsche 914 engine. Identical.

Compression, heads, cam, pistons, injection, ignition, valves, output etc. However while that does not make it ideal…..it definitely is NOT a bus 1.8L type 4 engine…..yet that is what application they built these heads to.
So the owner sends heads to shop…and instead of shop thinking….412 or 914…they think “bus”. It’s possible they never asked.

So…they put in new guides, valves, springs…and a minor step cut. This is NOT the normal step cut of .028” to .032" that you see newer head castings with.
This is a thinner 0.011” step….with the chamber floor flycut at a slight cant/angle…to increase deck volume while not taking much out of the bowl.

This GREATLY increased the chamber volume.

They did a few things quite well though:

1. As you can see in the picture below…they shaved the boss on the cylinder side of the head. This is good…in the respect that there is not that much room to go fly cutting in these heads before the cylinder fin contacts the head fin. And with the variations from cylinder make to make….that can get risky.

Here is why shaving that boss is good.

The lip on these 1.8L cylinders is 0.278”.

The same lip on my 1.7L Mahles is 0.275”

The bore depth in the 1.7 and 1.8 heads is normally about 0.250”….which means that had they not shaved the boss…the fly cutting that was already done would cause interference between cylinder and head fins.

Right now from the step to the machine outer boss is 0.226”. That leaves me 0.052” to play with. They will machine 0.026” from that leaving 0.024” between cylinder and head fins. If I need more I can shave a little more.

2. The seat work was good…not perfect…but good. The valve job is just basic…very good…but with a single angle on the exhaust. The seats could have been blended at the port slightly better.

3. It appears from the new machinists comments (and markings on the head)….who are used to building some very high end engines so they think critically about everything they measure…even on simpler engines like this….that the throat of the exhaust bowl was milled slightly during seat install…”throat cut” as it’s called. It increased the exhaust bowl to valve diameter ratio to 91.3%...which is a little better than average for the street.

So far all that has been done in this picture is some minor floor smoothing, CC’ing ports, chamber and bowls and measuring everything.

The valve bowl throat sizing will be done again as the exhaust valve is brought out to 36mm. Keeping as close to 90% as possible is excellent for a street engine the machinist stated. They know far more about heads than I do.

An important key will be sourcing valve seats that are correct for the valve size and have as much open center area as possible. This is a common problem on cheap replacement seats….that may fit say…a 34mm valve….but end up being so thick in cross section that they restrict actual “valve curtain” or seat flow diameter to as small as 25mm….before even subtracting the stem diameter.

4. The hardware on these heads…the springs appear to be Iskenderian brand. Good quality.
Retainers are stock replacements. The valve guides are accurate....technically..…but not perfectly smooth inside in the whole length.

Machinist stated that this is pretty common and has to do with the type of hone used. It’s actually a type of diamond “broach” as it was described to me…that…wobbles a little through the guide while expanding it. They have better equipment.

These springs have a few very small rust blemishes. They are going to be REM polished and checked. If they don’t pass…I have a brand new set of Crower springs that came in a cam kit for a very similar cam from the Type 4 store.

Valve guides are critical on everything…but much more so on air cooled.
The valves are not slouchy….but just basic good replacement level made by Ivam (Italy). Stainless with hardened tips. Very thin chrome on the stems. Not bad...not great.

In this picture you can see the thin step. The surface grinding to the floor and around the valve seat was the current machinist removing a small amount of metal…so he could see how the seat was installed. It was the install method that they were not totally happy with. It was noted that it appears the seat was slightly counter sunk and then the surrounding metal was peened in…which is “A” way to do it….but it could be better.

So…what is coming up:

The biggest problem…..is that the fly cutting that was done…has left the chamber volume with the step…at about 54cc. That’s huge.

And….with no other changes of additions…..meaning no cylinder shims or seals…that would leave the .024” deck we currently have and the 8.5cc piston dish and the .011” step….which means a compression ratio of 7.53:1.

While that IS better than the miserable 7.3:1 this engine came with….which ran hot….it is also the absolute extreme of deck that you can use in an engine like this…that also runs hot. Risky.

So….I am shooting….ideally….for

1. New 1st oversized guides from Automobile Atlanta are on the way.

2. Manley Racemaster 42mm x 36mm arrived a few months ago. 5 angle valve job.

3. New seats and proper minor unshrouding and matching

4. Fly cutting to remove the step of .011”…and a further 0.015” for a total flycut of .026”.

This will give a deck of .039”…and I will add right at .001” for sealing compound. So deck will be .040”.

In a perfect world that will give a chamber volume of 47.5cc (doubt it)…which will give a compression ratio of 8.12:1.

More likely we can hit a chamber volume of 48.5cc. With the .040” deck that is 8.01:1. Far more respectable than 7.3:1.

It may improve also because the larger valves and new valve margin will dump a ½ to ¾ cc…maybe.

Here are my cheat sheets for compression ratios if anyone can use them:

More to come! Ray

[raygreenwood]

A short update- 12-19-2019.

My apologies to the owner I am building this engine for that this is taking so long. Really it’s stalled on the heads.

The heads are moving along but they were kind of an in between job at this very busy but EXCELLENT machine shop and between me being in and out of town and traveling internationally from about April until my largest contract ended in November…whenever the machinist had time…. I was out of town. Whenever I had time they were in the middle of a production push.

OK…so some of the last pictures I posted will be re-posted to point out some details. I took some pictures last week with the valve seats pulled. The machinist has had some questions and concerns. There is nothing wrong with these heads and the castings. They will be excellent. However the degree of detail from when these were rebuilt about 10 years ago…..is disappointing (considering who the shop is)…and it’s what we will be correcting.

The gist is that these are 1.8L heads for a 412/914...and were remade for a bus.
The issues:

1. It appears according to the machinist….that either generic valve seats that are smaller than stock in the ID…...or even 1.7L valve seats were installed.

These seats were then “throat cut”…basically plunge cut or hand cut through the ID…to open them up. It left a VERY thin margin on the OD. With the type of metal these are…..which “appeared” to be a ductile iron seat…which are not ideal for air cooled…this thin margin (not much mass in the seat)…makes it hard to keep the seats in the head over time.

With the seats still in:

Seats out:

2. The machinist noted….that this is one of the common mistakes people make with rebuilding air cooled heads. Trying to get off cheap or not so much cheap…but with less work/effort…and not wanting to really machine seat ledges oversize. Yes…it is a concern…. realizing that its a critical operation because there is not much meat in these heads. Its one of the common reasons why seats fall out with heat cycling.

But putting in an undersized ID seat and throat cutting …is poor form. Cutting out excessive material….changes the temper and surface tension of a seat that has been installed with an interference fit. It will technically “loosen” the OD interference fit as the head and seat heat cycle.

3. To add to this, the ledges should have been cut with a chamfer in the corner to collect any chips or swarf that collect as the seat is pressed in. It appears that the intake seats still have the original factory chamfer but the exhaust were not cut with a chamfer.
The alternate and more common method is to chamfer the outer corner edge of the seats to leave a space behind it. Some shops do a little of both and work hard to keep the seat bore walls smooth to minimize the issue. The exhaust seats had a sharp edge.

So what level of workmanship do I expect from this shop? I am also putting in some pictures of my heads done by this same shop back in maybe 99 or 2000.

Mine are on the left. Next to them on the right are a set of stock, low miles head cores with stock valve size from a 1.7L out of a 412 so you can see what’s been done.

These are my old heads that will be rebuilt for my engine next year, are 1.7L heads but have 42 x 36 valves with high nickel alloy seats. These heads have had minor porting and valve unshrouding. They really needed to be flycut.

The unshrouding and port work created about 1.25 to 1.5 cc of extra volume. With the removal of the head gasket and shim I kept right at 8.0: or 8.1:1 compression ratio. A little low…but with everything else I did…web 73 cam….injection tweaks and better ignition and exhaust…it still ran fantastically. When I redo them…and do a little piston and deck work it will be 8.5:1.

Note how well the exhaust seats are blended

This is the intake seat detail. That thin shiny line is not a ledge sticking out. It’s the visible edge of a chamfer on the inner edge of the seat ledge.

Another view of the intake seats and intake unshrouding. The nicks from installing valve guides are not from this shop.
At about 70k miles I had a pushrod problem and had to have guides replaced on one head. It was my mistake and not a build quality issue. A different shop in Dallas installed the guides and left the marks.

This is a factory core head. Look at the big nasty ledge under that intake seat.

Undercut visible on both intake and exhaust factory seats showing that they were hand deburred before seats were installed.

Anyway…enough about my stuff. These pictures are just in this thread to illustrate what better workmanship these 1.8L heads will have.

So….we were speaking about valve seats last week. What to put in them. Yes….the stock factory seats were good. The high nickel alloy seats my heads have were harder, stiffer and machine smoother and handle a little more heat.
It was noted that on the 914’s and 911’s they have worked on (and yes those were for road racing)….they like to put in seats that can handle over 1400° F….that are cast to the proper ID and OD sizes so they do not have to be cut excessively risking changing the shape.
ACVW and Porsche are already a high heat application potential….mainly high constant heat. Not like a top fuel car or something…but they have their own heat issues.

Of course it was noted that when they use titanium valves…in a perfect world they like to use beryllium copper alloys. Pulls more heat out of the titanium which does not conduct heat as well as stainless.
Of course…we are not using titanium valves but are using damn good valves. And…Beryllium copper would be nuclear weapon level overkill …and a pile of cash…..and totally unnecessary. However it was mentioned that they have been having very good results in 914’s with some special alloy seats from CHE precision.

These alloys have a few percent beryllium copper but are a proprietary nickel, silicon, chrome and copper alloy (which is actually/technically a “bronze” seat).
They have been documented to pull heat out of stainless valves at a rate of about 2X that of normal nickel or iron seats…and therefore keep their expanded size better and require a little less interference fit. A bit more expensive but it’s what we are going with. They are cast in the correct size…only need a little ID blending. They should be arriving around January 12th…so I hope to have the heads ready to final flycut to set compression ratio by the third week of January.

So this is what we decided we are getting for seats. The exhaust and intake will be different alloys. They list them as their B-1 and B-2 alloys.

So in short…the work done to these heads about 10-12 years ago…was better quality than the factory….machine work wise. However some of the techniques….while adequate….are less than what SHOULD be used. The parts used (valves, seats and springs) were probably about equal to or slightly better than factory.

The machine work to put the step in….was not needed for this application and not correct for this application…and could have been a little smoother but was just fine.

The Manley valves we are putting in, type 4 store spring kit (possibly....although the springs already in these are pretty damn good) and the much better seats with better machine work should make these stellar heads.

More to come! Ray