Just did the H/C on my car and from the Dyno graph it was suggested that I check the preload on the Comp R lifters. Sooo...

How do I do that and if I need shims where can I get them? Is there a tool that will let me know that I have the suggested .002 preload? I hope this is just not a shot in the dark but that there is a way to measure.

Also are there adjustable rocker arms out yet that don't require machining the pushrod holes?

Thanks for any info.

 

Best bet is to get the adjustable rocker arms. With shims, youll get sorta close, but not right.

 

Ttttt

 

JMX's LS1howto.com has some info about how to shim a set of Yella Terra's on his rocker install page....

 

You can measure accurately with a dial indicater and a magnetic stand. .002" is not much, maybe an 1/8th of a turn on the rocker bolt from "0" lash...

Dan

 

Thanks for the link and the help. I have a few questions. So let's make sure I understand the how to article first. I need to get to zero lash by hand tightening the bolt with no rachet frist. At this point the pushrod should spin a little. After that I use the rachet to hand tighten and it should be no more than 1/16 to 1/4 turn. If more than that I need to shim.

Question #1 What is hand tight? This seems to be a very subjective term.

Question #2 If I need shims where do I get them and what size?

Question #3 Will using a touque wrench to get 22 lb/ft increase preload?

Question #4 Comp R lifters need .002 - .004 preload right?

Thanks.

 

FWIW I was watching HP TV yesterday, and they were installing the valvetrain on an old chevy big block I believe. They used a rachet to tighten the lifter slowly and gradually, while spinning the pushrod with their other hand. When they could no longer spin the pushrod, they gave it another 1/2 turn and said woohoo. Not sure how accurate this is or if it would not be the same for a more modern application.

 

Saw that but on a flat tappet cam not sure how critical lifter preload is. Thanks.

 

https://ls1tech.com/forums/generation-iii-internal-engine/141665-explane-lifter-preload-why-how-i-do.html

 

Determine current preload subtract the diff. you need to come out of lifter buy sheet metal , cooper at sheet metal supplier remove rockers trace stand cut and drill place under stand