Finishing a 2056 build with new 2L head castings, new WebCam cam, etc. Valve geometry done and SAT, so have custom lenght new Chrome Moly push rods. From all the searches it seems the consensus is zero valve clearance with these push rods and we also installed new genuine 911 swivel feet adjusters.

Can we get a general consensus to confirm ZERO running valve clearance is preferred?

or

IF not what is the recommended clearance?
Thanks

jjs3rd914

"0" clearance

Adjust the valves so that you can turn the swivel foot with a slight drag.

That's it. No feeler gauge required.

What they said.
Set it to zero. No feeler gauge. Just turn it in till it JUST touches and tighten the locking nut.

Zach

Zero,
The big thing to watch for is once done the PR should still be able to spin easy.

Yep. Someone once called it “loose zero” which seems like the perfect description.

THANKS for all the verification replies, a. Loose Zero. It is!

jjs3rd914

How bad a thing is it to set them to stock? I mean beyond that tappet sound?

Just noise, rattle, quite loud compared to aluminum PR's.

I've been doing zero for years with no ill effects, I used to run .004 but going to zero was a big difference.
Both T1 and T4.

So how does the noise compare between aluminum PRs at stock clearance vs. chrome moly at zero clearance? It's a question I've been wanting to ask. This seemed like a good time.

Sounds like a girl I knew in high school......

Definitely noisier, not too bad though, price you pay for performance cam.
Head work, heavier than stock springs, cam, etc., in my book CrMo pushrods are a must.
I only use quality Manton PR's.

There's no reason to use steel push rods on a stock engine.

Isn't there a requirement from Webcam for the valve lash?

Yes. But that’s intended for stock aluminum pushrods. They heat up and expand and will keep valves from closing all the way.

Another term often used is 'zero lash'

Anyone have a picture of the camshaft after running zero lash? I'm having a hard time with this spec.

Read this: https://www.dragzine.com/tech-stories/how-t...ash-like-a-pro/

Shane, I don't have pictures of cam wear when running zero lash, but I have pictures of valve seats and retainers that ran with excessive lash. That ticking sound you hear with loose valves is the valve train hammering itself. Do that at high revs on a race engine and the sound, if you could hear it, would be of the valve train beating itself to death.

The cam won't wear more because of a starting lash of zero and you can always check the lash with the engine hot after setting zero cold. Not fun, but do it once if you are worried you aren't developing clearance and adjust your cold settings accordingly.

I found a picture of my camshaft. Its just over a year old.
.006 intake
.008 exhaust
Track car only.

Is this from running lash? The Webcam folks seen it and thought I was at zero lash.

That could depend on a few factors ...

What did WEB spec for valve lash for that particular cam?
Correct cam break in procedure on initial start up with the correct oil?
What lifters are you running?
What push rods?
What spring tension?

The only time you should run 0 lash is when you run steel pushrods. The expansion rate on steel pushrods is the same as the cylinders, so they don't tighten up as they get hot.

When running the stock aluminum pushrods, you need to run factory valve lash settings. It accounts for the fact that aluminum expands more than steel when heated, so when your engine running aluminum pushrods is hot, it is at 0 lash. That's why you have to set the valve when the engine is dead cold.