The Money Pit

I finally got to put the timing tape on the balancer today and found my advance only pulls to 28 degrees with 10 initial. Every hot chevy I've ever read about calls for about 36 degrees in by 3000 rpms. I just had this distributer redone,but aparently he thaugtht I wanted it stock. I can't understand how that thaught could cross his mind with the idle shaking the whole car.Anyway it looks like a recurve is on the books for Christmas this year.Just wondering if any of you have had this done,and by a professional.
Were you happy with the results? :chevy


[Modified by The Money Pit, 8:21 PM 12/21/2002]

MoMo

A lot of misunderstanding here. Basically, your distributor should be curved to what your engine wants. If you have a mild cam, and you have one of the earlier distributors without a vacuum advance, you will have less timing advance. If your engine runs well and it's happy, don't worry about it.

You could advance your base timing to about 12 degrees initial as a start, and see how it runs. That serves to pull down your torque curve in the rpm range slightly. Basically, you can advance your timing to the point that it either starts to ping, or starts to overstress the starter, and then back off. That's often what we do at Denver's high altitude.

If you want your advance to come in sooner, then get an Accel recurve kit, which includes new weights and a variety of springs. The lighter you go on the springs, the sooner the advance comes in. And if you run a mild cam, then that can help your performance.

The "hot" Chevy's that you were referring to in all likelihood are running higher compression and more radical camshafts. They need the advance to be greater and come in later because of the power curve of their camshafts. So it all comes down to giving your engine what it wants.

If your mechanic didn't set your advance curve for 36 degrees all in by 3000 rpm, it was probably because that is too much for your engine. In other words, changing your curve alone will not make your engine one of those hot Chevy's. It's the whole combination.

I hope that's clear, if not, please explain further.
But yes, some improvement can be made in your spark advance curve, but you have to be careful.

The Money Pit

The curve I referred to was used on the motor I modeled my 406 after,which with iron heads pulled 455 hp and 498lbs of torque on the dyno with the mufflers and air filter on. I expect with the AFR heads and 1.60 rockers to be in the 500+ range,and feel the distributer could be holding back a few ponies.
I've heard of people getting their distributers recurved by someone that has a distributer machine. Of course the weights and springs technique would work,but is a lengthy trial and lots of error method that I'd like to skip.If anyone has heard of or used a vender for this was the question I asked.

Gordonm

I'm not in Pa. but I had mine done by a local machine shop that builds race engines. He charged me 45 dollars and set up the whole thing. Weights and advance. Mine works great now. I have 12 initial with 36 total all in by 3000. This works great for my motor.

CF6873

Check out Lar's paper in the tech tips and do it yourself. He walks you through the process and it's not that hard to do. Craig