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Sat May 01, 2010 6:07 pm

OK i am in conflict here. I am building a mild 2017cc motor and my builder doesn't want to shim the rockers if possible. I will give you my setup and then please assist:

DD 2017cc for bus
40x35 full p/p heads from Wolfgang Int.
ACE vw rocker shafts/arms
Web 163 cam (in between an engle 110 and 120)
Brand new AS41 case decked and machined at Brothers VW

Now if I were to use the adjusters with the pushrod side adjustment can I possibly get away with not shimming the rocker assembly?

If that would work, will the valve stem stay intact or will it prematurely wear?

Thanks, vwdon

Sat May 01, 2010 6:22 pm

who is the builder? they should know you have to setup the rocker geometry.

Sat May 01, 2010 7:55 pm

X2. You almost always have to shim the rocker arms when installing to get the correct height. whats his reason for not using shims? sounds like he's lazy, and wants something to just bolt on. there are absolutely NO downsides to shimming. better watch out for that mechanic. i sure hope he's doing all the nessecary adjustments and checks to the motor.

I recently bought a set of latest rage ratio 1.25 rockers, with solid bolt together shafts, with the adjustment on the pushrod side, and i didn't need any shims. obviously you will need shorter pushrods, i went with chromoly. i made 2 trips to and from tennesse in 2 days for a total of 600 Miles, and have since put another 400 miles on the car. just checked the valves today, and they didn't need any adjusting. i also have dual valve springs. so over 1000 miles, and everything is in perfect shape, no play anywhere.

Sun May 02, 2010 10:30 am

My builder is "old school" German. For the last 35 years all he has done is Type 1 upright motors. He loves stock motors and doesn't like to mess with the rocker geometry by shimming the rockers. Super old school German to say the least. Doesn't like to change the tried/true design of these motors. Perhaps I'll have him build it to the heads and I'll have Hot Rod Hayes does the rockers. I am going to get dual aluminum taper pushrods cut to length.
Thanks vwdon

Sun May 02, 2010 10:32 am

Shimming the rockers is the Ghetto way to set rocker geomerty. I DO NOT use rocker shims on any of my engines.

Sun May 02, 2010 10:36 am

What do you suggest?
Thanks vwdon

Sun May 02, 2010 11:30 am

No shims under my Scat 1.25 rockers either. Got shorter push rods.
You start putting shims under the rockers and then the adjusters hit the stock covers and shave metal which gets into the engine.
That old German has the right idea.
It all about the push rods and geometry.
I ordered a set of HD Alum push rods from aircooled.net but gave them the old measurement and they made them up before I caught my mistake.
had to have another set made. Costly mistake.
I felt like a complete dolt! #-o

Sun May 02, 2010 1:07 pm

Nothing wrong with old school german engine builders. For performance, I would have someone with more experience dealing with the intricacies of setting up a performance engine. Ive also had good experience with Scat Pro series rockers, 1.25 and 1.4's. Only problem i had ( yesterday) was a broken adjuster cup. IMO would be a good idea to have a few of those on hand for this purpose. Just my opinion on this matter. GL-Jon

Sun May 02, 2010 1:37 pm

I assume ACE rockers are German 1.1:1 on shafts with better retaining clips.
You will not need any shims to use stock rockers, perhaps just lashcaps to get a little more stem height in respect for your highlift cam.

If you add Porsche swivel foot adjusters to these rockers, shims may be needed to make up for how the swivel foot extends the stem height.
This is well known, CB swivels come with .060 shims in the package.

If you use a different kind of rocker, I don't know what will be needed to make them work best. For a DD stock rockers are probably a safer choice.

Sun May 02, 2010 2:44 pm

Yes modok Ihave the ACE German rockers 1.1:1 by Art.
So if I use lash caps can I use the stock German adjusters or will I still need the swivel foot (I actually have the Ford currier)?
Thanks vwdon

Sun May 02, 2010 6:46 pm

That's right, lash caps and regular(stock) adjusters should work fine. No shims, should be cheap and effective.

OR, you can use your ford swivels and no lash caps, but with these you ought to have at least .060 shims under the rocker blocks.
I prefer the porsche type swivels to the ford type, but I have run the ford type in two engines and nothing bad happened, so they work too.
Are fancy swivel adjusters needed with your mild setup? Naw, probably not needed.

Sun May 02, 2010 9:49 pm

Who makes the most durable lash caps?
Thanks, vwdon

Mon May 03, 2010 10:19 am

vwracerdave wrote: Shimming the rockers is the Ghetto way to set rocker geomerty. I DO NOT use rocker shims on any of my engines.

Did we ever get an answer as to why this is a bad idea?

Also, just because we have the typical old German mechanic doesn't mean he knows performance. We have the same guy in our town. He's fantastic. He has knowledge and skills for forever....and I don't trust him for a minute with my 1915. I've got the two 30-year-olds in the speed shop with a high-11 Bug for that.

Mon May 03, 2010 9:47 pm

So lash caps vs. swivel feet. What down side do lash caps have over not having to shim the rockers up with swivel feet?
Thanks, vwdon

Tue Oct 12, 2010 12:32 am

I spoke with Web and they recommend a 1.25:1 rocker sao I bougt the the scat billet rockers witht he adjuster on the pushrod. Tus after having pushrods made I should not need to shim the rockers. VWdon

Tue Oct 12, 2010 5:27 am

vw donvieira wrote: I spoke with Web and they recommend a 1.25:1 rocker sao I bougt the the scat billet rockers witht he adjuster on the pushrod. Tus after having pushrods made I should not need to shim the rockers. VWdon

Not necessarily true. The lack or presence of shims affects how the rocker tip contacts the lash cap. Take a look at the following picture:

I blued the lash cap and then cycled the motor. The wiped-away rectangular patterns show the places that the rocker pushes on the cap. In the above case, the shim needed to be taken away in order to center that wipe pattern more. Right now, it is too far up and will not be pushing the valve straight up and down the guide.

The other thing with the Scat-style 1.25s is that you have to take into account the adjuster screw itself. Go counterclockwise with it all the way so that the cup is resting against the arm. Now turn it clockwise (in) about 2-3 turns. This is where oiling actually occurs. Oiling does not occur with the screw turned fully counterclockwise.

Both of these issues show that pushrod length and shims ARE still taken into account with Scat rockers.

Tue Oct 12, 2010 6:05 am

pushrod length does not create correct geometry, correct geometry creates pushrod length

Tue Oct 12, 2010 6:47 am

Right, that's why I brought it up. It's too easy to just cut them and think that because the adjuster is on the pushrod end that you don't have to get a correct length and that's not the case.

Thu Feb 10, 2011 8:38 pm

What was the outcome to your rocker drama? I have just discoverd the same trying to set these up on my 2276. Apparently shims are not needed, but machining the rocker pedestals or rocker blocks to move the rockers closer to the head. That will move the wipe pattern closer to the centre of the valve. Is this the case. Rockers are the same scat 1.25 pro rockers.

Also have heard that the ratio on these is closer to 1.38!

Thu Feb 10, 2011 8:47 pm

deadkombi wrote: What was the outcome to your rocker drama? I have just discoverd the same trying to set these up on my 2276. Apparently shims are not needed, but machining the rocker pedestals or rocker blocks to move the rockers closer to the head. That will move the wipe pattern closer to the centre of the valve. Is this the case. Rockers are the same scat 1.25 pro rockers.

I had to do the same thing with a set of scat 1.25s.