LS1TECH - Camaro and Firebird Forum Discussion

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-   -   How should the rockers sit w/ heads off car? (https://ls1tech.com/forums/generation-iii-internal-engine/836561-how-should-rockers-sit-w-heads-off-car.html)

fast01 12-28-2007 07:49 PM

How should the rockers sit w/ heads off car?
 
This may be a stupid question, but I just got a set of Patriot LS6 style heads (035 castings) with their new .580/.590 225/229 114 cam. My question is, how should the rockers sit on the valvestem with the heads off the car (obviously no pushrods)? Is this even worth looking at or being worried about? Should I just worry about the wipe pattern when I get them on and adjust pusron length accordingly? The slot seems to be too far forward on the valvestem. It's not hanging over the edge, but it's not centered on the valve that's for sure. I thought, if anything, the rocker should sit off center towards the rear (closer to the rocker body). Can someone help me out with this? Thanks!

Randy WS6 12-28-2007 08:28 PM

The push rods holds the rocker up , a floating effect, balanced between the push rod and valve steam and the stud is pivot point the longer the push rod the more it moves the rocker tip forward or to the toe and the shorter the pushrod the more it moves it to the heel of the valve steam's ,If the push rod is removed the rocker arm will lay back on the valve steam

99mongooSS 12-28-2007 08:38 PM

confused!

vettenuts 12-28-2007 10:52 PM

I always set my wipe pattern on the work bench. Pushrods have nothing to do with the wipe pattern unless you are running fully adjustable rockers such as the Cranes and even then you can bench set them. Using checking springs on one set of valves and a dial indicator to measure valve movement, you can use a Sharpie to coat the valve stem and set the rocker height. If you don't have a dial indicator, use a ruler to measure you maximum valve lift and then mount the rockers and use the rocker to open and close the valve with your hand. You will easily obtain the wipe pattern. Right now you are in the best position to set this up, then once the heads are on the car use the rocker setup established on the work bench to measure the required pushrod length to obtain the proper lifter preload.

The pushrod has no affect on wipe pattern with LS1 rockers if properly set up.

fast01 12-28-2007 11:30 PM

That's good info vettenuts! Now, to correct the wipe pattern I need to shim, correct? It looks to me like the pattern is going to be too far forward, but I'll have to get a checking spring on there and see what I come up with. Adding shims (if this is correct) to what area will move the pattern where? I appreciate the help!

ssheets 12-29-2007 12:14 AM

Man I'd like a nice set of adjustables...not sure what they'd gain me, but I'd sure like em.:D

Die Grinder 12-29-2007 02:02 AM

I think the answer depends on your goals. Do you want to maximize valve guide/stem life? Do you want to maximize seat to seat valve duration for a given cam lobe, thus affecting your DCR? Do you want to maximize net valve lift? Do you want to maximize positive posts from LS1TECH members who will applaud your attention to details that the average hack doesn't care about?

vettenuts 12-29-2007 06:19 AM


Originally Posted by fast01 (Post 8384743)
That's good info vettenuts! Now, to correct the wipe pattern I need to shim, correct? It looks to me like the pattern is going to be too far forward, but I'll have to get a checking spring on there and see what I come up with. Adding shims (if this is correct) to what area will move the pattern where? I appreciate the help!

Check them first without the shim. I think you will see the wipe pattern is closer to the intake side. To correct, the shim will raise the fulcrum of the rocker and move the wipe more towards the exhaust. The shims "should" center it on the valve stem and you will see it is very narrow, usually 0.060" or less in width once you get it right. Once you figure this out on the bench, then this will be the setup you use once the heads are on the car to measure for your pushrods. Pushrods should be the last part you order, except for the celebration beer :chug:

You can leave the checking springs right on the head until you install so you can take your PTV measurements, then once that is done swap out the springs.

PREDATOR-Z 12-29-2007 08:30 AM


Originally Posted by Die Grinder (Post 8385205)
I think the answer depends on your goals. Do you want to maximize valve guide/stem life? Do you want to maximize seat to seat valve duration for a given cam lobe, thus affecting your DCR? Do you want to maximize net valve lift? Do you want to maximize positive posts from LS1TECH members who will applaud your attention to details that the average hack doesn't care about?


Can we keep it tech please?
You seem to attack what other poeple post, yet you do not input any concrete LSx tech to support your attacks.
Basicaly your attitude sucks, so if you have good things to share, please do, otherwise perhaps you should :gtfo:

fast01 12-29-2007 01:29 PM


Check them first without the shim. I think you will see the wipe pattern is closer to the intake side. To correct, the shim will raise the fulcrum of the rocker and move the wipe more towards the exhaust. The shims "should" center it on the valve stem and you will see it is very narrow, usually 0.060" or less in width once you get it right. Once you figure this out on the bench, then this will be the setup you use once the heads are on the car to measure for your pushrods. Pushrods should be the last part you order, except for the celebration beer

You can leave the checking springs right on the head until you install so you can take your PTV measurements, then once that is done swap out the springs
Cool, thanks! I thought that's how it was done, but just wanted to make sure. I appreciate the help!


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