Connecting Rods tight - Now a Stock Rebuild Thread

[Kalen1970]

History: These are stock rods that came out of a running 1600SP build I put together when I was 19, and first bought the car. I assembled (didn't build) the parts all together, and surprisingly lasted 8000+ miles on the build. The car sat for the last 3 years, water got in the engine, so its time for a rebuild. I'll be re-using most of the parts. Except new P&C's and a CW crankshaft. The old crankshaft is a cast LEPE crank. My plans for this engine is a little more then stock. I'm going to bump up the compression a bit, probably use the CB Cheater cam, and ship the SP heads off to brothers for a rebuild and possibly some port/polish work done.

I took the rods to a machine shop here, to have them rebushed and balanced end to end. The machinist said he honed them a bit on the small side (which I'm fine with. Its easier to take metal off then add metal). The odd thing is, he said all 4 rods measure the same. Which is weird, because two definitely fit and two don't. I've tried the tight ones on all the journals.

I've asked him to hone the two offending rods out by .001. This should give me about .0015 .002 oil clearance. They should be done either by end of today or tomorrow. I'll report back.

Also wondering if I should invest in a set of micrometers that will measure down to .0001
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1970 - Separated from the Pan again for a proper rebuild *fingers crossed*

[nsracing]

For checking rods dimensions and out-of-round, a dialbore gauge is best.

Set of inside micrometers w/ corresponding outside micrometers you will need also to find proper dimensions.

Telescoping gauges are not good enough for rod work. For cyinder spigots they are fine or opening heads.

[Kalen1970]

Got the rods back from the Machinist.

They fit now. The two unmodified rods have an oil clearance of .0015. The two rods that where previously tight and honed out .001 today have an oil clearance of .002.

I'll run them as is. I put the .002 rods on journals 1 & 2 (pistons 3 and 1). I have not modified the bearings in anyway.

Now to figure deck height.
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1970 - Separated from the Pan again for a proper rebuild *fingers crossed*

[mark tucker]

that should work.if you want them at 0015 just take a little off the cap.

[Kalen1970]

[modok]

It is preferable to deck the case, because that has the potential to be a good improvement over how it is now. The cylinders are usually made very fairly tight tolerance, while the case on the other hand, the crank and cylinder seating surface can be .010+ out of parallel with the crank front to back.

it is possible to adjust the size of the rod bore by sanding the parting surface, but.... you'd be best to not do that. it only works well if they are freshly cut flat, and there is no rule that says they need to be flat across, in fact they probably are not. I bet your machinist angle-cut them to put them on the lowside.........and speaking of that, the spec I gave you is not the same as in the book. I add .0005" to the rod spec from VW, because I have run into this so many times before. If the bearings have too much crush it will tend to distort and be less round when bearings are torqued in......and when you get down under .001 clearance then all it tales is a little distortion to make an area of zero clearance. So, it is very possible to have all four rods the same size without bearings in them, but two tight with bearings in... TOO much crush!!

[Kalen1970]

[modok]

He probably already re-cut them when he did them the first time.
I'm just trying to close the can of works mark opened up........you see if the angle of the parting surfaces changes just a small amount, the rod goes out of round....and I think that your rods are probably angle cut based on the fact your machinist shrunk them....because that's how you hone a hole smaller..by cutting the parting surfaces and putting a slight angle on them too...so I think if you try it you will be visiting the machine shop a third time.
YEAH I KNOW IT"S possible Tucker but it's not likely

.002 clearance is very good. Leave that alone.
i bet your cam and main bearings won't be anywhere near that ideal, good thing they are less critical

[nsracing]

LEAVE IT ALONE! It has already been re-cut and re-honed. If you go scraping shit off the caps you will end up w/ out-of-round big end and cocked bearings.

The rod caps were cut on the ends so they are shorter -if you will - and then installed/torqued to specs. Now they are undersized again and out-of round. So you have to re-hone them back to size so they are round again and have the proper dimensions to hold the bearings in place. The machine shop done all that. Had to be done twice but at least it is right now.

Don't make me come out there and beat you w/ a stick.

As Modok already pointed out, the case is your best bet to modify or adjust so you have the proper deck height tolerance you are looking for.

Around 0.080" is about stock...so it is not too bad. We have already been corrupted/spoiled so we cannot work w/ large decks like that.

Mock it up on all cylinders and see what deck heights you have.

[Kalen1970]

Put the sticks away! I'm not going to touch the rods. Except maybe to try my hand at the "Oil Squirter" mod. Overkill for a stock engine I know, but it would be to practice my hand at it for a 2109 build I'm slowly accumulating parts for.

Now that you guys explained how the rods might be cut, that also explains why I'm over .080 deck height. Using the deck height tool. I'm 2 1/8 turns in before it touches. Now granted I only mocked up one cylinder and kinda roughly just measured to get a ballpark idea of where I am. I'll do some more thorough measurements throughout the week.

I'm not sure how much I like this deck height tool, and I'm contemplating picking up a depth micrometer, or at the very least, I'll need a set of bent feeler gauges. I'm not completely sold on the screw method. It involves me making sure its completely flat before measuring. Which for me, brings in way too much human error into equation for my liking.

Also, I'm following Alstrup's 1600SP build here http://www.thesamba.com/vw/forum/viewtopic.php?p=6870518#6870518
I'll be upping the CR, getting the heads massaged, Still contemplating cams, but I'm leaning towards the cb 2280. I think I might experiment with 1.1 rockers on the intakes, and 1.25 on the exhaust, for a poor man's split duration.
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1970 - Separated from the Pan again for a proper rebuild *fingers crossed*

[Kalen1970]

So I've measured the Deckheight:

#1 ~.0795 - .080
#2 ~.0775 - .078
#3 ~.0775 - .078
#4 ~.0775 - .078

I used the deck height tool and a couple tappit feeler gauges (pre-bent) I would then remove the feeler gauges and measured them with calipers and double checked them against a micrometer.

How much would you guys recommend I deck the case? .03? .02?

Again, this is a stockish build, A deck between .05 - .06 is what I'm aiming for. I guess in the end this is a question I should be asking my machinist. What level of accuracy can he obtain...

Again, thanks in advance.
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1970 - Separated from the Pan again for a proper rebuild *fingers crossed*

[modok]

oh, .020 to .025
IMO .060 "in the hole" is just as good as .050, anywhere in there is good

[Kalen1970]

[modok]

Honestly that's very good. Over .010 variation is common...... just in the rods
Is the .002 in the case, the crank, the rod? who knows, don't worry about it

[Kalen1970]

[Kalen1970]

So I got the case back from the machine shop. I've only had the chance to mock up #1 cylinder, but now i'm measuring a deck height of about .0475 .048. I really hate using the feeler method. I'm thinking of just waiting until next month's paycheck and picking up a depth micrometer http://www.amazon.com/Mitutoyo-128-105-Micrometer-...micrometer

Also, now the #1 cylinder is way to snug/tight when fitting into the case, took a couple of hits from a rubber mallet to get it to seal. It fit in cylinder spot #2 just fine. I"m guessing the opening needs to be de-burred or something?
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1970 - Separated from the Pan again for a proper rebuild *fingers crossed*

[66brm]

Confirm the cylinder isn't contacting one of the webs inside the case now that its been decked, as the cylinder reaches further towards the crank now.

Or if its just tight, a quick cleanup with some emery should give the clearance needed
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Aust. RHD 66 Type 1
Aust. RHD 57 Type 1 Oval

[Kalen1970]

Ok, been a while. But slow progress has been made.

Cylinders 3+4 Deckheight measure .050 Right where I want it. I ended up purchasing a depth micrometer. I secure both cylinders with angle iron, and verify that the piston is at TDC using a dial gauge.

My current problem is the deck height on cylinders 1 & 2.

#1 = .042
#2 = .036~.037

The case was decked, but I think the machinist just took metal off the case, and did not verify that the 1-2 side was parallel to the crank center. Here are some pictures to show the differences on the case deck/cylinder height.

#2 - Flywheel side

#2 - Pulley Side

Here, my straight edge across #2 bumps against #1.

Another measurement sans cylinders

Hopefully this illustrates the difference between the decks on the case

What instructions do I need to give to my machinist?
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1970 - Separated from the Pan again for a proper rebuild *fingers crossed*

[modok]

Unfortunately these type of things take three times as long to do wrong and fix than to do right in the first place

The tops of the cylinders should be flat across, any more than .001 variance in the middle counts as a problem. I could not tell the guy how to do his job without knowing what kind of machine and setup..........but uless he misunderstood that the head is one piece....... maybe you better find a different guy with better equipment.

[Kalen1970]