Do these cause any problems with the stock chip? My car is idling erratically and showing around 14 grams at idle. Appreciate feedback from those that have installed this mod.

 

Make sure all the bolts are trq-d to spec.

your vacuum should be 17-19/20"

-you have a vacuum leak

 

I actually just put my comp 1.6 roller tip rockers on my 91 two days ago and all is well. Not a huge difference per say but it definitely runs much better. Throttle response is much improved and it goes through the revs much better. Took my cam from 202/207 @.50 .413/.428 to 205/210 @.50 .441/.457. So basically just a touch smaller than a stock LT1 cam.

 

So you did end up going with 1.6s? Good man!

 

well I already had them sitting in a box from my ZZ5.0 build so I figured hell I might as well use them lol. I'm still planning on the ZZ4 cam swap when the funds allow.

 

If it was OK before the swap,,, going to 1.6 rockers won't make much difference to vacuum or idle. Make sure the pushrods are not rubbing the pushrod hole - it shouldn't be. Then,, readjust the preload - I usually go 1/2 turn from zero on the stock type lifters. Sounds like you have them run down too much - too much preload won't let the valves totally seat and will cause a rough idle/low vacuum.

 

I agree with BadSS. That is exactly what happen to me when I installed mines.

 

You go a 1/2 turn? I usually go 1/4 turn and all seems fine. I've heard some even go to 3/4 turn.

 

I don't know if you're trying to fix your idle issue with new rocker arms but I would fix the idle issue first before doing anything else.

 

Pulled out the old vacuum gauges and both are messed up. One showed 5.5Hg laying inside the toolbox. Hooked up it was around 22 at idle. The other gauge is a lost cause.

Not trying to fix the idle with rocker arms...already an issue with the stock ones. Just wanting to make sure the additional air does not throw off the ECM. As RobertFrank indicated it is not really an issue apparently with his car. Went half-turn past 0 lash, but there is a slight tick on the driver's bank...?

 

It depends on the lifter. If they're stock and have some miles on them,, I'll go 1/2 turn. If they're new with the good retainer clips I'll go 1/4 turn. The last few set of flat tappet hydraulics I've used and installed were the Pro Magnums with a recommended preload of .002 - .004",, which is a little less than 1/8 turn.

 

The correct way of doing it is getting the correct length pushrod for the new, bigger rockers, so it's centered on the valve and you don't bust valves.