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Mon Dec 01, 2008 7:35 pm

gerg wrote:

True true . . I had to cut different length push rods for each side of my case. I can only presume the cam bore is not perfectly centered in the after market aluminum :( case . . . Whether it be poor case work or a base circle problem on the cam.

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This is always a pisser. In so far as I know, VW never used any cases that were this far out but the problem shows up with some frequency in cases that have been align-bored, usually by some shade-tree type with a portable cutter.

Good shops typically use real cutters for align-boring, often built on the chassis of an old lathe. This generally prevents any side-to-side misalignment. By the same token, the good shops usually will not accept such a case for rework. However, if the asymmetry is only a couple of thou it is easy enough to clean up by adjusting the depth of the cut made to dress the deck height.

But the real message here is the one heard from the novice builder who, having spent a mint on a pile of parts to build the 'perfect' engine, discovers that damn few of those parts fit right out of the box. Indeed, probably half of my writing is toward the fellow with just one engines-worth of parts, trying to explain to him the realities of after-market parts and the absolute necessity of being allowed to check their specs right there on the counter, before pulling any money out of your jeans.

-Bob Hoover

Fri Dec 05, 2008 1:13 pm

gerg wrote: I run 1.25 rockers on the normal studs in the 044 head and a solid rocker shaft kit from another company.

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The image shows another of those 'unimportant' details, in that the valves are installed at an angle of 9.5 degrees. Unless your dial indicator is also set to 9.5 degrees you will get a different reading every time.

'Aw that's not important," the 'expert' sez....

In fact, there are dozens of these 'unimportant' details that when combined will GUARANTEE the engine will not run as well as it could.

-Bob Hoover

Hint: The fixture holding a dial indicator should be sturdy enough to allow you to zero the dial without seeing even the slightest amount of movement of the needle.

-Bob Hoover

Sun Dec 14, 2008 6:29 pm

I count 4 or 5 unanswered questions about rockers with the adjuster on the push rod side. Does anybody have any tips and or pictures of a good setup? I’m setting my 1.25’s up right now and want to make sure I’ve got it right before I cut my pushrods. I would like to see how the rocker sits on the lash cap at 0, ½ and full lift.

Mon Dec 15, 2008 7:02 pm

juki48 wrote: I count 4 or 5 unanswered questions about rockers with the adjuster on the push rod side. Does anybody have any tips and or pictures of a good setup? I’m setting my 1.25’s up right now and want to make sure I’ve got it right before I cut my pushrods. I would like to see how the rocker sits on the lash cap at 0, ½ and full lift.

I don't know if this will help you, but it's the only pic I have of where on the pad it should rub on the lash cap....I colored it with a black sharpie. I do believe the rocker was slightly offset to the right on the lash cap when all was said and done. That might not answer your question, but it might help someone.....? I was told this all looked good.

Here's a few pics of my geometry with this style rocker...

no lift (if I remember right)

full lift

half lift

Wed Dec 17, 2008 10:24 am

thans for the pictures! I think I'm on the right track. I have a slight angle between my adjuster and pushrod at 1/2 lift so I think I'll try a shim.
the rocker contacts about 3/16" on the lash cap, pretty well centered vertically.

Wed Dec 17, 2008 7:56 pm

Bob Hoover wrote: gerg wrote: I run 1.25 rockers on the normal studs in the 044 head and a solid rocker shaft kit from another company.

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The image shows another of those 'unimportant' details, in that the valves are installed at an angle of 9.5 degrees. Unless your dial indicator is also set to 9.5 degrees you will get a different reading every time.

'Aw that's not important," the 'expert' sez....

In fact, there are dozens of these 'unimportant' details that when combined will GUARANTEE the engine will not run as well as it could.

-Bob Hoover

Hint: The fixture holding a dial indicator should be sturdy enough to allow you to zero the dial without seeing even the slightest amount of movement of the needle.

-Bob Hoover

Yep, all I have ever tried to do was parallel the valve stem as best I could from all angles. Not sureI have the precision to get it exactly 9.5 degrees though.

On another note, Ollies found that the deck on my case was .006" off from one side to the other :evil: :evil:

That explains the different length push rods I had.

I should be cutting new push rods this weekend or next week after I get the long block together.

Wed Dec 17, 2008 11:09 pm

gerg wrote:

On another note, Ollies found that the deck on my case was .006" off from one side to the other :evil: :evil:

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Yup. I've even seen them on a bias... TAPERED from rear to front by nearly sixty thou.

A good engine needs a good foundation.

-Bob Hoover

Thu Dec 18, 2008 9:22 pm

When I set mine up, I READ THE CAM CARD, measure the ACTUAL ratio of the rocker arms, then install everything. Get the valve to 1/2 lift and make sure the pushrod and the valve stem are at the same height from the valve cover gasket sealing surface of the head. It's always worked for me, and I've never had abnormal wear on any valvetrain parts. Every stroker motor with ratio rocker cam (ie. Engle FK series etc.) has needed shims under the rocker blocks, and usually longer studs as well. I use a cheap $12 adjustable pushrod, available from most VW parts stores. Also, you can make an inexpensive mount for your magnetic base dial indicator. A piece of 2" angle iron, with 2 holes in it, bolts onto the exhaust port.

Thu Dec 18, 2008 9:51 pm

if you are cutting your own 'custom' length pushrods, why would you ever need to shim the bases?

Thu Dec 18, 2008 11:47 pm

Because with the valve at half lift, you want the tip of the pushrod and the tip of the valve to be at the same height. My turbo motor is running CB Ultramag Plus heads with a cam similar to an Engle FK-44 (SLR custom grind), with Chinese 1.4's, and I had to put .030 under the rockers. Another turbo motor I built with a cam similar to an Engle TCS-20 (again an SLR custom grind), with AutoCraft 1.25's needed .060 under the rockers. If you move the rocker assemblies further from the heads with longer pushrods, or closer to the heads with shorter pushrods, will GREATLY change the valve lift.

Sat Dec 20, 2008 3:58 pm

Hint: The fixture holding a dial indicator should be sturdy enough to allow you to zero the dial without seeing even the slightest amount of movement of the needle.

-Bob Hoover
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Yep, all I have ever tried to do was parallel the valve stem as best I could from all angles. Not sureI have the precision to get it exactly 9.5 degrees though.
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I took a picture of the fixture I use but I can't figure out how to make it appear here. A little help would be appreciated.

As for ensuring you've got the angle nailed down, here's how I did it:

Starting with a factory-new head, I inserted a length of 8mm precision-ground drill-rod into the guide. The rod was about 12" long so it extended some way above the rails of the valve gallery.

The foundation of the fixture is a piece of aluminum bar stock, 1" on a side to which I have affixed a piece of 1/4 x 1" aluminum angle which is tilted 9.5 degrees... or WHATEVER VW de Mexico is using :-) Once I had the correct ANGLE I drilled & tapped the extrusion to accept a dial indicator, one that has the mounting lug perpendicular to the case of the dial.

The whole idea here was to come up with a fixture that would hold the dial indicator at the same angle as the shaft of the valve. This was done by using a ROLL PIN to affix the piece of extruded angle to the piece of bar stock, allowing the extrusion to PIVOT on the bar stock.

The extrusion was drilled for THREE roll pins. Initially, only the middle of the three was installed.

I made provision to EITHER clamp or bolt the 1" bar stock to the rails of the valve gallery.

When the extrusion was a PERFECT MATCH to the angle of the drill rod, the extrusion was clamped into position. The fixture was then removed and ANOTHER of the holes for a roll-pin was drilled and a roll pin was installed. The fixture was then checked against the head & drill rod. When I was satisfied with the fit, I drilled the hole for the third roll-pin.

The position of the Dial Indicator was determined by trial & error using a new head fitted with valves. Once I had that nailed down I drilled & tapped 1/4-20 hole(s) to secure the dial indicator to the fixture. A rib on the case of the dial indicator indexes it to the extrusion, allowing the indicator to be bolted to either side of the extrusion.

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As you can see, the device isn't very pretty. You can also see that it's sturdy as a brick shit house. It has withstood about 30 years of service. I think I made drawings for this and my other home-made jigs & fixtures back in the 1980's. They were published along with the HVX modifications.

The purpose of this fixture is to set the valve-stem height of the head, which is installed in ANOTHER fixture. The fixture shown can NOT be used with an assembled head as the rocker arm shaft will interfer with the 1" bar. But you CAN make such a fixture using cast precision plate (ie, 'tooling' plate).

The second fixture (not shown) allows you to set the rocker-arm geometry whilst working at the bench. All measurements are relative to the rail of the valve gallery. So long as care is taken to ensure the head 'thickness' is maintained (ie, the distance between the valve-gallery rail and the combustion chamber sealing surface) you will be able to achieve an accuracy of about +/- .001"

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The goal was to illustrate a truly sturdy fixture; I believe this one fills the bill. At the same time, I've a hunch it would be silly to go through this much trouble for just ONE engine, but it does offer a nice example of the work needed to produce a properly assembled engine.

-Bob Hoover

Tue Dec 30, 2008 10:46 pm

Having an issue with a pair of bugpack 1.25 ratio rockers. It's almost like the rocker stands need to be shaved down to get the rocker to contact the valve stem in the right spot. I'm putting together a 1904 with B pistons and a set of single port heads. The combustion chambers on the heads are pretty small, so I was able to get away with the B pistons a 0.040" shim to get the compression ratio I was looking for. Cam is a Webcam 218. These pictures were taken at zero lift (no pushrods in) for ease of picture taking; but I tried setting it up (with and without shims) and I quickly realized I wasn't going to get the rockers to contact the valve stem even close to the center of the "pad". Somebody enlighten me. What did I do wrong here and how do I correct it?

With a bunch of rocker shims

With no shims at all

Thu Jan 01, 2009 6:56 pm

Where's the lash caps?

Do the Sharpie trick on the lash caps to check the wipe pattern not the rocker pads. You are trying to keep the rocker assembly from pushing or pulling the valve stem and distorting/wearing the guides. The wipe pattern should be centered across the face of the lashcap.
Adding shims under the rockers will push the wipe pattern away from the rocker shaft and removing shims will pull it back towards the rockers.
Also, there are lash caps with different heights available. These effectively lengthen the valve so you shouldn't need to reduce the heights of the rocker stand pads. I believe BERG still has caps that will add as much as .125 to the length of the valve.
If you concentrate on getting the wipe pattern correct then the pushrod length and relation to the cup adjusters should fall in place.

Thu Jan 01, 2009 7:39 pm

Dougy Dee wrote: Where's the lash caps?

Shit, I knew I was forgetting something. It's been a while since I've done this. Thanks for the help. :D