I thought I would post about my adventures over the last week or so, in the hopes that it might help some one out as we have seen a lot of tunning / timing type questions lately.
Last week I got it in my head that I wanted to play with the timing on my cuda.
Honestly, it was a slow week at work and I wanted something to do during the evenings, and I love to tinker.
So I tried a few different springs in the dizzy...took out the very light aftermarket spring and tried the heavy stock spring with the long loop along with the lighter factory spring.
I noted that the timing was bouncing at idle so I thought the stronger spring might help. It did.
I have previously "welded up" the inside of the slots in the dizzy to limit total mechanical advance to around 18 degrees.
With that combination, I found power was really down.
I tried a few different combinations over the last week or so and settled on a light aftermarket spring and a medium stock spring (not sure where it came from but it is a little heavier then what was in there).
ON my test drive tonight the car felt good, best power of the few combinations I tried. My only concern is that it takes a little while for the timing to come in...its all in around 3000, maybe a little more.
The initial is set at 20 degrees, idles at 750 rpm in D, timing is nice and steady on the timing light, and pulls 10 degrees vacuum at the manifold.
So after my drive I turned my attention to the carb...trying clean up the AFR at idle, and while the idle mixture screws mad an impact, I found that the ported vacuum was pulling the same 10 degrees as manifold vacuum. So obviously the primaries are open too much and the carb is not working on just the idle circuit.
So I worked on that and got the vacuum down to 0 on the ported vacuum port. Not sure why the idle screw was in so far but it was. I had to open up the secondary a little to close the primaries enough to get the vacuum down to zero. Played with the mixture screws again and got the AFR to around 13.5 - 14.0 at idle. Idle is not about 700 in D...but still nice and steady.
I am looking forward to seeing how the car works now that it is idling on the idle circuit. I am hopeful it will provide better idle quality, and be crisper off the line! I know I will probably have to adjust a few more things on the carb now to get it right...but that's ok, I love this stuff!
I think the key is, remember that the timing and carb are linked, if you change one, you may need to adjust the other...and don't for get to recheck everything.
Happy tuning!
Jason
