Zero Valve Lash

Lees73Super · Post by **Lees73Super** » Mon May 13, 2002 10:38 pm

Just sort of a poll on how all of you set your steel pushrods to zero lash.

I set mine so my rod spins very freely, this is still kind of noisy but I feel a little more secure about my valves closing completely.

how tight do the rest of you make them? ever had any problems?

Lee

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One of these days ill get this stuff right!

73 Super, 2110, 120 cam, 2x 44 IDFs Hyfire CDI and some more fun stuff.

Ed Brewer · Post by **Ed Brewer** » Mon May 13, 2002 10:44 pm

That's how I set mine, free spinning but I cannot rock the rocker. Over 4000 miles on my 2110 and no problems.

Marty · Post by **Marty** » Tue May 14, 2002 9:15 am

I run them at .004.

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Marty Staggs
www.staggsracing.com

Lees73Super · Post by **Lees73Super** » Tue May 14, 2002 12:51 pm

Valve lash is the gap between the foot on your rocker arm and your valve stem when each particular cylinder is at top dead center. Checking/adjsuting it is an important part of the maintenance of your aircooled VW. Stock VW's with stock pushrods are supposed to be set at .006, but with steel or chromoly steel rods, lash is debateable. Less lash = less noise but a risk of a burned valve. More lash = more noise but ensures against burned valves/cracked heads etc.

mharney · Post by **mharney** » Tue May 14, 2002 1:09 pm

To a point.. but too much lash is just as bad as not enough.

alcast81 · Post by **alcast81** » Tue May 14, 2002 1:33 pm

Oh ok , yeah i know waht you guys are talking baout , i just didn't know thats what it was called. thanks for the help.

fastfood · Post by **fastfood** » Tue May 14, 2002 6:03 pm

Ok, nobody said it, but the reason the VW spec is .004 or .006 cold, is because they use aluminum pushrods which expand, therefore closing the gap as the pushrod expands. That is why with the steel pushrods people say to go with zero lash. That is how I understood the argument. Anyone else got anything on that?

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Rice, it's what's for dinner!!!

alcast81 · Post by **alcast81** » Tue May 14, 2002 11:00 pm

I have seen a lot about this topic on here, but i dont' really know much. If someone could just explain to me what valve lash is , i would appreciate it , i been wondering that for a while now. thanks

Matt Harris · Post by **Matt Harris** » Tue May 14, 2002 11:29 pm

I set mine at .003".

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Matt Harris
78 x 90.5
2007cc
1971 Super

Post by **sparkmaster1** » Tue May 14, 2002 11:33 pm

I set mine at a snug .004"

danimal · Post by **danimal** » Wed May 15, 2002 10:21 am

>>>Ok, nobody said it, but the reason the VW spec is .004 or .006 cold, is because they use aluminum pushrods which expand, therefore closing the gap as the pushrod expands.<<<

not according to the bentley manual... remember, we are talking about solid lifters here... valves MUST have the proper minimum lash to live a full life.

>>>To a point.. but too much lash is just as bad as not enough<<<

not enough lash will definitely burn the valve, and cause it to run hot... the excess lash that comes with chromoly pushrods on a warm motor will not hurt parts at all, even tho it's way beyond the factory clearance you get with aluminum pushrods on warm motor.

go read the pushrod faq on my website for more info, including that bentley reference.

dan
oceanstreetvideo.com

Pablo · Post by **Pablo** » Wed May 15, 2002 5:25 pm

The stock aluminum pushrods expand at the same rate as the rest of the engine. That's why the lash is pretty much the same on a fully hot engine as on a cold one. When using steel pushrods, you set the lash at zero when cold because that's the best you can do. The lash will be a tad sloppy when the engine is hot, but that's the trade-off for a rigid pushrod. (You can't set them when hot, as the valve will not be sealing properly when the engine cools down.)

This really is an area that the cam manufacturers should have spelled out a lot more clearly. Mild cams are NOT supposed to be run with .012"+ valve lash, but this is what you get if following their hazy instructions.

Paul

Shad Laws · Post by **Shad Laws** » Wed May 15, 2002 6:00 pm

Hello-

Chromoly pushrods expand much, much less than aluminum ones. Set them to where the pushrod just turns freely, that's about zero clearance. Readjust every 3,000mi like normal.

Take care,

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Shad Laws
LN Engineering
http://www.lnengineering.com

Greg Ward · Post by **Greg Ward** » Wed May 15, 2002 8:35 pm

Paul is absolutely right.

Our cam grinder specifies the settings for each grind of cam he does.

All relate to Aluminium pushrods only, but some grinds are the standard .006" some are 0.010", and split duration cams may have different settings for intake and exhaust.

I'm sure he would not go to all this trouble if it wasn't important to the performance of the cam.

Chromo whilst virtually unbreakable, I think are a bit of an unknown quantity, unless the maker of the cam says they are ok, and they are set at the correct lash setting.

I tried them once and my 0.009" settings went to over 0.025" when fully hot and the car performed horribly.
No doubt it would have been better if it had been set at 0.002" or something, but there is no way it would have been exactly 0.009" when hot, as the cam grinder specified.

My 2c

Shad Laws · Post by **Shad Laws** » Wed May 15, 2002 10:38 pm

Hello-

<B>I tried them once and my 0.009" settings went to over 0.025" when fully hot and the car performed horribly.
No doubt it would have been better if it had been set at 0.002" or something, but there is no way it would have been exactly 0.009" when hot, as the cam grinder specified.</B>

Check out aircooled.net's HD aluminum pushrods... super strength and a good expansion rate

.

I still use chromoly pushrods in my personal engine, but then again, I also have hydraulic lifters...

Take care,

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Shad Laws
LN Engineering
http://www.lnengineering.com