Anyway, I used my dial back timing light because that is what I have, and because other than TDC and a mark at 35 degrees, there are no other marks on the balancer The car had a rediculous amount of initial timing, close to 30 degrees plus the 20 degrees of mechanical advance. It is amazing to me it ran as well as it did. I backed it down to 20 degrees initial and 40 total. MUCH better, part throttle surge GONE, runs great especially after I adjusted idle mixture after the timing change. My wife is taking it to town today, 30 miles each way, to see if the running hot problem has gone away as well.
I hope you didn't hurt it with 50 degrees of advance.
Please bare with me as I am really trying to learn the correct way to time an engine, and to do that, I need to know why you need to do what is needed. Does that make sense?The same thing occurs at steady-state highway cruise; the mixture is lean, takes longer to burn, the load on the engine is low, the manifold vacuum is high, so the vacuum advance is again deployed, and if you had a timing light set up so you could see the balancer as you were going down the highway, you'd see about 50 degrees advance (10 degrees initial, 20-25 degrees from the centrifugal advance, and 15 degrees from the vacuum advance) at steady-state cruise (it only takes about 40 horsepower to cruise at 50mph).
Anyways, why would the guy running 50 degrees mechanical advance (30 initial and 20 centrifugal), be hurting the engine, but when using 50* timing with the vacuum advance in addition, it is okay.
Lets say I set mine at 16* initial, and the centrifugal advance from the HEI adds in 20* in by...lets say 2800rpm.
Assume my car cruises on the highway at 3000 rpm (4.10 gears with 28" tires). To cruise on the highway I do not need to have it at WOT, so would there not be vacuum advance added in to get me close to 50* timing?
Is it only because there is no real load on the motor? I just don't see why 50* at 3000rpm in one situation is worse than another.
Next edjucation I need is to read up on tuning a carb with a vacuum gauge
bill (back in class studying :yes: )