Timing Question

[howzzzit]

Originally Posted by Chaparralman1974

Morning gang!

I know that it has been a while since I followed up on this, but it has been hectic around here....moved on from the timing issue to the bed and final assembly of the truck, so I am now back to tuning the motor.

I just wanted to post a follow up as I hate incomplete threads....LOL!


Ok, so here I am as of today.

I have the mixture screws set to max vacuum (15" Hg)....that is the max I can get it. I also moved the vacuum advance from ported vacuum to manifold as I have read on this, and the Chevelle and Corvette forums that is the preferred way to do it without emissions. At idle (600RPM) with the vacuum advance connected I am getting 26* of timing now. I am supposed to have 34-36* of advance at 2800 RPM with no vacuum advance....but I am barely getting 30*....so I will have to change out the springs in the dizzy.....it still seems to have a bit too much of a lope in it....it may be the cam though....it has an Isky RV cam. I called Isky and they said it was a mild cam....so I am not sure if it is correct or not. I have my base timing now set at 12*. The guy that built the carb and the dizzy said I needed 10*, but when I set it at 10* it seems way too retarded and runs a lot hotter.

I had it at 15* initial advance connected to ported vacuum and it ran down the road great, but hot restarts were a little tough....I don't think it's due to heat soak as I don't have headers and the starter seems to be a good ways away from the exhaust (it is a factory single exhaust system).

Also, I got the oil pan issue fixed....finally!! It was the blue Felpro 1 piece gasket that was the issue. I ended up just pulling the motor out so that I could work on it on the stand. I went back to a traditional 4 piece (cork and rubber) gasket and it sealed up nicely with zero leaks! Of course, as I reinstalled it I got a little gorilla handed with the wrench on the starter and broke one of the damn mounting ears...Oy Vey! So, I have to fix that now, but all in all she is running better.

I will report back when I change the dizzy springs and let you all know what happens.



Clay

I

I too have a lousy vacuum gauge. I set my quadrajet by best lean idle. I have an innova that works fine. Shows idle and timing. I gave up on the vac gauge and set the best lean idle by rpm. Set your timing and idle rpm where you want it to be. On a warm engine screw in the drivers side idle slowly until idle starts to drop. Screw it out and obtain the highest idle on the meter. At some point it will start to drop. Go back to the highest idle. Say your initial setting was 700 and it's now 800. Adjust idle screw to 700. Do the same with the passenger side. Set to desired idle if changed. Then do both screws again. This will give you best lean idle. It effectively is doing the same as a vacuum gauge. Works for me.