Am I being paranoid? Lifter noise? (video)

[smokinss]

Its about .060 Don. 1.5 turns to 22ft-lbs from zero lash. Looked up a article and guy figured .040 per full turn from zero lash. This is a estimate though. Picking up a pushrod checker this weekend

[ILuvPizzaTimes10]

1.5 turns is over .080 if i remember right. 1.5 turns is pretty tight.


and Joe can i take a crack at it???????

[SLP IROC-Z]

sure

[smokinss]

Here is the article I read

FWIW, EVERY cam install I have done using the LS7 lifter with a cam with greater than .600" lift (read smaller base circle) AND stock heads w/GM MLS gaskets has taken 7.425" pushrods for ~.050"-.060" preload. We measure lifter preload on each and every cam install we do. I have never had a lifter failure nor do we end up with the dreaded "sewing machine" noise.

Its very simple, If you change ANY of the following:
valve sizes, valve job, head milling, thinner/thicker head gaskets, decked block, cam with an altered base circle, etc... YOU MUST CHECK FOR PROPER PUSHROD LENGTH.

I have helped countless numbers of individuals with this process over the phone, via email, and PM's. I've posted the process on at least 3 occasions.

Here it is again in a nutshell:

1. Using the EO/IC method, get the lifter to the base circle of the cam.
2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn wtih a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.

For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...

I might not know everything but I will tell you that this method has worked for me year after year cam swap after cam swap. We average 3 cam swaps a week here so you can do the math.

If you are not familiar with the EO/IC method for determining valve events in a 4 stroke engine, its very simple:
For a given cylinder as the Exhaust valve is Opening, the intake lifter will be on the base circle of the cam and lash/preload should be checked for that intake valve.
For a given cylinder as the Intake valve is Closing, the exhaust lifter will be on the base circle of the cam and lash/preload should be checked for that exhaust valve.

THIS METHOD ALWAYS WORKS!!!

Check it using the above method and see where you are.

Thanks,
Shane

[SLP IROC-Z]

they say one turn is .047 but its funny cause when setting a given amount of preload in the checker the bolt method doesnt match

[Slowhawk]

One turn is not .o47 or .060.

I prefer 1 full turn which is near .080".

[SLP IROC-Z]

thats what i found, .075 of preload added to the checker was 1 full turn.

[SLP IROC-Z]

i will break out the digital torque wrench and set it to torque angle when my new pushrods come in and find out the exact degrees vs preload.

[smokinss]

Well then I guess I have too much pre load? If 1 turn is .080 then I am damn near .120. I will check it again this week after work.

[ILuvPizzaTimes10]

yeah i agree. 1 turn is around .080 and your target. loser is ok on a high rpm all the time engine. but for stock-ish .085 is GM's spec. on a sied note i run mt LS7 lifters at .040 pre load (1/2 turn) and there is no noise.