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Randall C
Randall C, ASE Master Tech
Category: Chevy
Satisfied Customers: 12744
Experience:  ASE Master, L1, 32 years, Diagnostic / Electrical Specialist
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valve lash on 350 ci/ 355 hp zz4 crate motor..hydrolic..lifter

Resolved Question:

What is the valve lash on 350 CI/ 355 hp zz4 crate motor with a hydrolic roller lifter? All information I have varies from 1/8 turn to 1 full turn. What is correct?
Submitted: 4 years ago.
Category: Chevy
Expert:  Randall C replied 4 years ago.

Tracer :

Hello, My name isXXXXX will do my best to assist you. I am working with your question now and will return shortly

Tracer :

Can you tell me why you are doing the valve adjust? routine? or new heads? or something else?

Customer:

new crate motor ---on start up the valves rattled. Brand new engine

Tracer :

I will gladly send the info and will but.,. a crate engine should have pre set with valve adjust and not reuired to do so. if you are just wanting to recheck. i will send info. LMK

Customer:

You are right but they still were loose and made noise. so I looked in my manuals that I had which directed me to do 0 lash plus 1 full turn. However, the spec sheet with my new engine said 0 lash plus 1/8th turn. Which one is correct?

Tracer :

got it. please allow me a couple minutes to type up and send. thanks

Tracer :

Ok, done many of these. 1 turn is 100% correct HOWEVER .. in all the years and all I have done? 1/2 -3/4 turn is ideal. 3/4 turn being the ideal. the problem is accuracy. I know of 37 years how to feel the pushrods for zero lash. , it takes practice. you may? judge them 1 way, i judge another so.. thus why 3/4 turn is the best.There is no way the lifter will not be centered at 3/4 turn. 1 turn? yes.. thats the 100% specs. i am sending you margin for error. the lifters ONLY need to be close, not all 100% dead on. all you are doing is centering the lifters. Rule of thumb? try to keep all at same turn. I think this will work. If you click

Attachment: 2012-05-24_003453_333.pdf

Full Size Image
ou can upload a .pdf file showing the 100% GM way

Tracer :

did not work. hang tight. i will try again

Tracer :

Click HERE

Customer:

I did exactly what you just sent me, but summit racing ( who we bought the motor from) said to set the adjustment to a 1/4 turn on the roller lifters....1 full turn as you stated would hold the valves open to long and affect performance, so now I have your way, 1 full turn, the spec sheet that came with the engine, 1/8th turn, and Summit racing tech line, 1/4 turn????????

Tracer :

ok, big difference. you now say roller rockers. i thought we were dealing with factory crate. Pleas advise

Tracer :

i do see you said in question "rollers" sorry. missed that. 1/8th -1/4 no more

Tracer :

you are ok with either. 1/8th being better but getting exact between 1/8th and 1/4 is difficult.

Customer:

roller hydrolic lifters It is factory crate but has roller hydorolic lifters, aluminum heads, 750 cfm carb. 355 hp I ran the engine for 20 minutes at 1 full turn. Have I damaged anything?

Tracer :

I dont think so. but get back to the 1/8 turn

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