Ok i got a pushrod checker from jegs (7"-8.170") and when this is how i used it. I need to know if this is correct....


1. Took two rockers off that where off there lobes (int and ex).

2. Put the adjustable pushrod down the hole and tightened a rocker arm over it to 22 lb ft.

3. Adjusted to zero lash and then carefully took the rocker arm off and the checker out.

4. Counted number of turns (7 2/3 turns) then did this

7" + (.050" x 7 2/3) + .060" (lifter preload)

and came out with 7.44333333".....


Is this reasonable with all stock ls1 parts but with 5.3L heads that are unmilled and using autozone stock replacement gaskets?

If this is correct what length should i get? Also how do i know if i am doing this on a lifter that hasnt bled down because that would mess the numbers up wouldnt it....I cant push it down when i put the pushrod in and push. Is this normal or should i be able to feel some bounce in the lifter?



Sorry for all the questions...Let me know what all you valvetrain gurus have to say
Thanks!!!

 

Ok i was using the pushrod checker wrong......i'll fix the original post

 

anyone?

 

Did you measure the pushrod checker when you removed it? If so just add the amount of preload you want.

 

Yes....i measured the pushrod and then added preload and came out with 7.44"

What i want to know is if this is reasonable or am i doing something wrong....if this is correct would i be ok with using 7.400" pushrods?

 

did u make sure that the lifter u are checking on, is on the back side of the lobe of the cam?

 

Yes that's reasonable and ordering the 7.400 pushrods would be perfect.

 

Ok well then i guess i wont be needing new ones then....why have some people been telling me that i will need shorter ones?

 

7.400" is too short. You will only have 0.017" preload. I would use 7.450" pushrods based on your numbers.

 

.020 preload isn't a bad thing

 

Two recent conversations with engine builders have indicated more preload is producing better dyno numbers. I wouldn't run stock lifters with that low a preload, any pump up and you will be tagging the clip, which is a very wimpy piece.

 

Stock lifters According to your calculations 7.450 is the length you should run.

 

Who were they? I'm sticking with .020, I've talked with several builders as well one with several records to his name.

 

How do i know that i wasnt checking the length on a lifter that has already bled down? That would mean with the length that i had on the adjustable pushrod, it would be bottoming out the lifter right? And isnt that bad

Right now i just have the 7.400" stock pushrods in it and it seems to be alright

Let me know what yall think

 

You would have to push down pretty hard to bleed a lifter. The valve spring will take several minutes to bleed it down and the force is 70% higher than seat values, likely a couple of hundred pounds. With brand new lifters the plunger will move more easily though.

 

You shouldn't have been putting any pressure on the lifter at all. And I say that the 7.4's are good to go. If it measured out to .017-.020 that should give you best hp without running a 0 lash set-up.