Comp Pro-Mag 1.6 roller rockers - using comp nuts/polylocks
3/8" studs

I got them set at 1/2 turn now. I read a couple threads elsewhere that some are setting at 1/4 turn. Sounds like too little preload, but what worked for you?

Either is fine. The key is making sure you are at zero lash AND on the base circle of the lobe for the rocker you are adjusting.

I usually go 1/4 turn, tighten the lock nut, then snug the rocker nut another 1/8th.

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Once the poly lock is tightened the rocker nut aint budging on mine. What is the advantage to only going 1/4 turn? Is it an issue that the valves won't fully close if too much preload is adjusted into it??

Thanks

No advantage at all. If you rev it high enough to float the valves it doesn't make any difference what the preload is. Later! Frank

I have the stock lifters with a CC503 cam and Summit 1.6 rockers. I went 1 full turn with mine as that is what is suggested in the repair manual. I have hit the rev limiter several times setting up the trans governor and am now shifting near 6000 rpms and have not heard the slightest sign of valve float or have any problems at all. I was really considering 1/2 turn but I figured since I used the stock lifters I'd use the stock preload. I don't know of any advantage of going with less than 1 turn of preload, does anyone else?

Usually go 1/2

Anyone read TPIS' positive results by setting preload at TWO FULL TURNS FROM ZERO?

Jake

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Got a link? or reference?

I've heard they suggest 2 full turns. I think that is too much. Too close to the bottom of the lifter in my opinion, then if you do have a lifter pump up at high rpm's you are risking piston to vavle clearance. I was going to go with 1/2 turn but decided to do 1 full turn. Next time the rockers are off I want to try 1/2 turn but I had so many variables this time with swapping everything above the block including the full ignition system I really wanted to go with a preload I had ran previously with the same lifters. So far so good.

I've always used 1/4 turn. I set them running too. Back off until they rattle, tighten until they just quit making noise, then 1/4 turn. I've turned hydraulic lifter engines to 7k setting them this way with no problems.

The idea is to get the pluner inside the lifter just barely above centered. Too low and they will "pump-up" they can't bleed down fast enough. too high and they bleed too fast and collapse.

Setting them running is a bit messy, but the guesswork goes right in the drain too.

I just did mine with 1/2 turn, even though Crane says 1 1/2 turns. I also let the engine run while adjusting the rockers.
Like TimAT said, it's a little messy but it's the only way of doing it right.

Arnold

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Thats the way I was taught to do it in school. On my 85 monte i did it without the car running and i guess it came out alright. Next time i do this i am going to get a set of valve covers and cut holes in it in accordance to the locks. Then i am going to tighten it down that way. Whats nice about doing it with the car running is you can actually hear when it is correct.

DG