[CatalinaMike]

Anybody have a set of these lifters and know their pushrod length. Need a starting point. Do you check these.....tighten rocker down till no more bounce in the pushrod and then 1/2 turn? turn over twice and check wear pattern? Thanks for any help and nothing is too basic

[lust4speed]

Just having a set of the Comp lifters won't be enough to help you out since different rocker arms require different length pushrods, and the difference between stock heads and different manufacturer's aluminum heads will also change the required length. You are pretty much going to need an adjustable pushrod to find your specific length needed.

Since there is no oil in the lifter, the pushrod plunger will continue to depress. I usually count the turns from zero lash (when slack is taken up) to bottoming out. say it is 2.5 turns which would be about 2.5*.050"= .125". If the preload is stated to be a half turn, then that is .025", so I would fully depress the plunger, go for my desired pattern, and then add an additional .100" (125-25) to the pushrod length for ordering. If the plunger depression is only 1.5 turns, then that would be .075" travel and subtracting the .025" desired preload, I'd add .050" (75-25) to the pushrod length for ordering.

[CatalinaMike]

Thanks This will help. 1.5 HS rockers and 6X-4 heads. Tool will be here tomorrow. Had one but wasnt sure about the lifters depressing as they had been sitting in oil I'll see what numbers I came up with when I check again. 8.65" seemed a little off to me but I will know

[AG]

What are your valve lengths?

[lust4speed]

Whoops, add that variable to the list...

[David Jones]

Fresh seats?

[Skip Fix]

Don't remember for sure what mine are but they are way short than my flat tappets that are close to the same as my Comp solid rollers. They are in the 8" range not 9s .

[flamedabone]

I built a 400 2 years ago with a Comp roller cam/lifters and E-heads. The pushrods were 8.650. I built an identical 400 this year, the pushrods were 8.750.

No idea what was different, I suspect Comp changed the total height of the lifter body, but I was too lazy to investigate, I just put in the longer pushrods and let her fly.

This is the pushrod length tool I used to find the right length. Super simple to find what you need.

https://www.summitracing.com/parts/cca-7902-1

-Abone.

[CatalinaMike]

Ok. Tool came in today. Did a few test measures and came up with the one at that measured at 8.697 If anyone sees anything wrong in the pics please let me know. Measured at 0 lash +1/2 turn. (First valve stem pic was when I forgot to tighten the setscrew and it twisted)

[Schurkey]

Originally Posted by lust4speed

Just having a set of the Comp lifters won't be enough to help you out since different rocker arms require different length pushrods, and the difference between stock heads and different manufacturer's aluminum heads will also change the required length. You are pretty much going to need an adjustable pushrod to find your specific length needed.

There's so many variables it makes a person's head spin. Don't forget block deck height, material planed off the head, cam base circle, pushrod-cup height in rocker and lifter, to name a few more. Still not a comprehensive list.

Originally Posted by lust4speed

Since there is no oil in the lifter, the pushrod plunger will continue to depress. I usually count the turns from zero lash (when slack is taken up) to bottoming out. say it is 2.5 turns which would be about 2.5*.050"= .125".

Accurate for 7/16-14 thread, on rocker studs.

Originally Posted by lust4speed

If the preload is stated to be a half turn, then that is .025", so I would fully depress the plunger, go for my desired pattern, and then add an additional .100" (125-25) to the pushrod length for ordering. If the plunger depression is only 1.5 turns, then that would be .075" travel and subtracting the .025" desired preload, I'd add .050" (75-25) to the pushrod length for ordering.

All of your distances are accurate for the rocker-stud NUT. They're not accurate for distance at the lifter, (plunger depression--plunger travel) due to rocker ratio.

OTOH, since "shelf-stock" pushrods come in .050 increments, it's not necessary to be perfectly accurate with pushrod length.

Originally Posted by CatalinaMike

wasnt sure about the lifters depressing as they had been sitting in oil

"Soaking" lifters in a pot of oil does NOTHING useful. Common procedure, but a total waste of effort.

I pump them full of oil using an oil squirt-can and an inch of rubber hose. Then I have to be really careful when adjusting lifter preload, so I don't push the valve open, into a piston. Gotta let the lifter bleed-down during the procedure.

Originally Posted by flamedabone

I built a 400 2 years ago with a Comp roller cam/lifters and E-heads. The pushrods were 8.650. I built an identical 400 this year, the pushrods were 8.750.

No idea what was different, I suspect Comp changed the total height of the lifter body, but I was too lazy to investigate, I just put in the longer pushrods and let her fly.

"Comp" doesn't change the lifters, the supplier(s) they buy from changes from time to time, what's sold as "Comp Cams" is actually made by someone else, and that "someone" may not be the same from month-to-month.

You did right--adapt to the situation you have, order pushrods to suit.

Originally Posted by CatalinaMike

Ok. Tool came in today. Did a few test measures and came up with the one at that measured at 8.697 If anyone sees anything wrong in the pics please let me know. Measured at 0 lash +1/2 turn. (First valve stem pic was when I forgot to tighten the setscrew and it twisted)

Scrub distances seem wider-than-optimum. Understandable if the first photo is from a mistake in procedure, but even the second photo shows a wide pattern. Can you adjust the pushrod length to narrow the pattern?


Be aware that there are AT LEAST three different ways to measure a hollow pushrod, and that's NOT the way Comp Cams does it.

But again, pushrods are shelf-stock in .050 increments, so absolute precision isn't needed.

[CatalinaMike]

Exhaust valve 5.01626 (S2631) Have to find the intake specs....put them somewhere. Deck and heads only light decking. Cam: Hyd roller .365 lobe lift. Rockers HS 1.5 Yes scrub distance was too wide (.080) with my blind self but was dead center. I tried to do the Straub method for setting rocker geometry but to get the rocker parallel to the retainer the lock nut was not engaged.

["QUICK-SILVER"]

Taller than stock valves, moves the tip of the valve stem closer to the rocker stud. That moves "narrowest sweep" out (exhaust side of head) on the tip of the valve stem.

If you can't get in the ball park with right angle method, you'll probably need different length rocker studs or polylocks.

Perfection on this may not be the best for longevity if narrowest sweep is too close to the the edge of the valve stem. At least without more work, like adding lash caps.

Roller rockers are very forgiving when it comes to being just right.

Clay