Erratic Timing
Well the sight plugs finally came in and I got the chance to run a few tests, which now confuse me more than ever. I must be doing something wrong.
First, my balancer had 3 marks on it, and I thought I should double check TDC to make sure I was using the right one. Sure enough, my previous measurements were based off the wrong one, which appears to be maybe 20* advanced. The factory groove is correct at 0* TDC. I reset the initial at 12* and got it to idle down to 600 rpm in gear.
Bonehead mistake. I should've caught my TDC mixup right at the beginning so I didn't waste your time, but I really appreciate all your help with the timing diagrams, Mattax!
That verified, I had someone run the motor up to 4000 and noted the timing, which I marked in red.
I must be doing something very wrong to be getting a curve like this. The Distributor slots allow for 30*, which should put me at 42* at some point. What is with that spike at 2500 rpm? The engine really seems to want more initial timing, like 15*+. I'm really holding it back at 8*-10* I'll try hooking the vac advance can up to manifold vacuum and seeing how that changes things. I'm gonna go back out and check these numbers again, and I still have to check more precisely how the advance moves from 600-1000 rpm.
Well the sight plugs finally came in and I got the chance to run a few tests, which now confuse me more than ever. I must be doing something wrong.
First, my balancer had 3 marks on it, and I thought I should double check TDC to make sure I was using the right one. Sure enough, my previous measurements were based off the wrong one, which appears to be maybe 20* advanced. The factory groove is correct at 0* TDC. I reset the initial at 12* and got it to idle down to 600 rpm in gear.
Bonehead mistake. I should've caught my TDC mixup right at the beginning so I didn't waste your time, but I really appreciate all your help with the timing diagrams, Mattax!
That verified, I had someone run the motor up to 4000 and noted the timing, which I marked in red.
I must be doing something very wrong to be getting a curve like this. The Distributor slots allow for 30*, which should put me at 42* at some point. What is with that spike at 2500 rpm? The engine really seems to want more initial timing, like 15*+. I'm really holding it back at 8*-10* I'll try hooking the vac advance can up to manifold vacuum and seeing how that changes things. I'm gonna go back out and check these numbers again, and I still have to check more precisely how the advance moves from 600-1000 rpm.