I just got done doing a bunch of top end maintanence on my wife's '91 RS with the 3.1. See this thread for the details-
https://www.thirdgen.org/forums/v6/4...-1991-3-a.html

Basically, new timing chain, resealed intake, 1.6 roller tip rockers. Good Mallory sprial core wires and AC plugs. Fresh air filter. Timing set 12* initial. New 16pph injectors from Racetronics.

When it is warm (closed loop) and you floor it when it gets to about 3800 on up it just labors, takes forever to pull to 5 grand where it will upshift. Seems MUCH better when cold, like I pull out of the driveway and stab it. Otherwise, it just is a dog from 4 grand up. It used to pull right to 5000-5500 when you stabbed it before it upshifted and pulled strong right to the end. Now it won't.

Can't detect any kind of missfire nor spark knock.

Otherwise it seems to actually pull better if I back off the pedal, say 7/8ths pedal instead of full. Throttle body was decarboned too.

I have 40+ psi fuel pressure on a mechanical gauge from the fuel rail read thru my windshield when this is happening.

Is it possible the 1.6 rockers are making it go lean in the upper RPM's? I do not have any codes, and am in the process of getting an ALDL cable to datalog it to help find the problem.

 

How did you adjust the rockers? Any excessive noise fromt the heads?

 

Absolutely no noise. Starts, idles, runs at cruise like a dream. Actually will go 85 down the highway just fine, as long as you ease it up there.

I adjusted them by turning the engine over via a socket on the crank and when each cyl was at TDC of the compression stroke, I ran the locknuts down to zero lash and 1/4 turn. The intake was off so I could watch each cam lobe to be sure it was on the outer base circle, and I did it in the firing order, checked it twice.

In order to remove the valve covers and set it running, you'd have to pull the intake manifolds, pull the covers, and reinstall the manifolds to run it, then pull all that of to put the covers on. I ain't doing that! There are some things about the 60* engine I don't like, and in the third gen F body chassis the crap that's in the way of the passengers side cover is right up there.

 

I always thought that people were supposed to go 3/4 turn, I forget. Pulling the UIM and MIM isn't that bad.

 

its 0 lash 1/2 turn

 

I had to go at least 3/4 on my rockers

 

u know what now that i think about i went 1/2 turn and had to go back and put another 1/4 turn maybe a lil more on mine

 

you both may be right, when I bought my 60* cam from crane it called for 1/2 to 1 full turn, I split the differance at 3/4. But on a running sbc I take them 1/4 turn after they quit ticking though.