1.6 Rocker Arm Issues

[Weston19]

Just finished installing these on my 3.1. I used the iron head studs, and supplied locknuts and pivot balls. I set the preload at 1.5 turns, and the motor runs great. 1.5 turns with the 2.8 iron head studs is the proper preload if you have stock headgaskets and havnt decked the heads. I still have great vacuum.

Edit- this is using the comp cams 1.6 rockers. Not sure if it will make that much of a difference. But i will say again, 1.5 turns is the right amount of preload. The rockers have a tad bit of side to side play but up and down they are tight.

[geoffinbc]

Side to side play is normal. Head gaskets or milled heads make no difference. Zero lash is always your starting point. The only variables in the equation are the thread pitch and the rocker ratio

[1988GTU]

I used the 3/4 turn method. I so hope I do not need to turn them another 3/4 turn. It is litterally a PITA to get at the back ones with everything reassemabled. What kind of vehicle do you represent Weston19?

[gpse3400]

Dont forget, if you want 1.6 rockers but dont wanna pay much or revamp the rocker system on gen 1's and gen 2's, '93-'95 3100's used 1.6 rockers. Readily available used and affordable.You will notice extra power.

[1988GTU]

It runs. Although, now I am experiencing like a 'lag' / hesitation from about 2500-3500 rpm range. What could it be? If I had a way of recording the sound I would, but I don't.

[Weston19]

Im represtenting the j body crowd. I have an 88z24 with bolt ons. So far i have a wai, lightly ported heads, lightly ported lim and uim, waiting on a 57 mm tb, i have a full exaust (2.5-dual 2') 5 speed, bully stage 2 clutch, accel wires, ngk plugs, ffp pully and only 160 000 kms on the motor. Last year with my old car, a 91 rs, the motor and tranny did a 15.7 @88 mph. Thats with stock exaust, a bully stage 2, and a wai. The cars not ready for the road yet, but i took it around the block to check the new brakes (92+ front upgrade and dodge daytona 11 1/4 rear discs and notice some nice power gains. Motor runs smoother, has more grunt and makes power a little further up in the power band. I need a chip now, im pretty sure that ive started to tread on thin ice with the stock tune, and i have enough bolt ons to take advantage of the extra spark and fuel.

Im really hoping that next spring i can land a 14 second slip. I realise its going to be a very high 14, but non the less, 14's are in my targets. I also have this planned out so that most mods that ive done can be transferred over when i finally go 3x00. If i can get a good launch and keep my 60'er under 2.2 seconds, i should be able to sprint to a high 14 run.....

[1988GTU]

Update~
It runs, have not gave it a streetable drive yet, but in a hour I will. One thing I did notice was a lope in the idle which was very much expected. I still have to hook up the air intake since it will bog/die during a cold start with a good goose of the throttle. I hope that is the cause.. So far it has a total of 1 & 1/4 turns. I was going to go that extra 1/4 turn but I wanted to see the outcome of the way I did it first.

[1988GTU]

I will say they did make the midrange powerband increase noticeable, but for some reason it lost 99% of all of it's upper end power (past 5000RPM) for what it did have. Also I'd like to state that they are quite noisy. I might go back in and give them an additional 1/4 turn.

[1988GTU]

I'd like to add that I am more than likely going open up the rocker covers again to give them all a good additional 1/4 turn since I notice the engine to load up after idling for a short time period.

[tractorman]

Case in point:

If it ain't broke, don't fix it!

[1988GTU]

It likes to load up to the point it will stall. I cannot have that.

[tractorman]

I was referring to the whole thread. I know it's a hobby and all... but if the car is running good, then there's no good reason to take it all apart on a quest for 5 more horsepower.

But much like the U.S. involvement in Iraq, you're already in this mess up to your neck... at this point you just need to get the car running right again.

My guess is that you've tightened those rockers TOO MUCH rather than too little. Those instructions you posted clearly state that you should tighten them between 1/2 and 1 turn... meaning that 3/4 turn would be ideal. I don't know what you mean by "loading up", but here's what I'd do. I'd readjust all those rockers carefully (both valves fully closed for EACH cylinder), then I'd put it back together and make damn sure that all vacuum lines and wiring are put back properly.

There's also the possibility that you've burned or warped valves, as you've already run the engine with the valves too tight. That'll allow combustion gas to squeeze past the seat (resulting in that "pop" you heard), and it'll ruin valves in short order- seen it more than once on diesels when somebody adjusted the valves wrong. If straigtening out the lifter preload and vacuum lines/wiring doesn't take care of it, then a compression test might be in order at this point.

[1988GTU]

When it popped I didnt run it for hours or anything like that. I just ran it for a minute until I heard that pop. Now when I said pop, it could mean just slightly to you or the other way around... if that and then I re-adjusted it some and it went away. Too bad it's obd 1 otherwise I'd watch the fuel trim and oxygen readings. I can understand if this was a 2.2 or something and then yeah, I would leave well enough alone.

[tractorman]

If you didn't run it too long with the valves too tight, then I'd guess that the valves are probably alright. I still wonder if your rocker adjustment is too tight, though- even at 1 1/4 turn. Going from 1.5 to 1.6 rocker arms shouldn't make a big enough difference to make the car run poorly with stock tuning- assuming that everything was put back correctly and is working properly.

[Weston19]

I was referring to the whole thread. I know it's a hobby and all... but if the car is running good, then there's no good reason to take it all apart on a quest for 5 more horsepower.

But much like the U.S. involvement in Iraq, you're already in this mess up to your neck... at this point you just need to get the car running right again.

My guess is that you've tightened those rockers TOO MUCH rather than too little. Those instructions you posted clearly state that you should tighten them between 1/2 and 1 turn... meaning that 3/4 turn would be ideal. I don't know what you mean by "loading up", but here's what I'd do. I'd readjust all those rockers carefully (both valves fully closed for EACH cylinder), then I'd put it back together and make damn sure that all vacuum lines and wiring are put back properly.

There's also the possibility that you've burned or warped valves, as you've already run the engine with the valves too tight. That'll allow combustion gas to squeeze past the seat (resulting in that "pop" you heard), and it'll ruin valves in short order- seen it more than once on diesels when somebody adjusted the valves wrong. If straigtening out the lifter preload and vacuum lines/wiring doesn't take care of it, then a compression test might be in order at this point.

No man. Im telling you 1.5 turns if your using the 2.8 studs. if your not then thats ur problem. And Its not even like this is a difficult procedure. It can be a little tricky, but its so straight foward its not even funny. Not to mention that even if its "only" 5 horsepower, your also benifiting from the reduced friction. Remeber that the instructions are for the 2.8 iron head, not the aluminum head. The gen 2 heads have splayed valves and different lenght pushrods, while the gen 1 top end is a non splayed design with pushrods all the same length.

My motor runs much better now. With the other supporting mods i have it really made a big difference. Remeber these motors have trouble breathing at top end, so a little extra lift will help. BTW, im pulling 22 inches of mercury at idle around 900 rpms.