Quench area trouble

Hey Don, how many deg. of advance do you get out of that?

 

advance

To be honest I don't know. I had an oiling problem and pulled the motor before I had a chance to time and check the advance curve. I can tell you everything is stock "like 1969" except the bushing and the mallory electronic conversion kit. (springs, weights, vacuum advance,etc.) I had a really bad ping that was inconsistent at various rpm's. I took the distributor apart and found no bushing. After replacing I had more power and no ping. If someone could measure the OD of their bushing and post it I could make some.

Don

 

Don what is the ID of the bushings that you made? I have a machine shop here at work that I'm sure could make me some. I wouldn't mind having a couple of different ones to play around a little more with the timing curve.

 

ID

Jason,

I can't remember. I think it's .1875" I made it from 5/16" brass round stock. I will get one and measure and post for you tomorrow or Wed.

Don

 

Stock GM fibre bushing is .300 long, fits .1875 shaft, is .250 in diameter.

The problem with the stock distributor points cam holes is, there are many different lengths used, which give many different total advance settings, and some use the bushing, some don't.

To make matters worse, some of the setups use a center cam that stops the curve just fine for engines revved below a certain rpm, qand when these settings are revved past a certain rpm, the weights over-center on the curve, and continue advancing.

That is shy I need to see the cam plate, to determine which one you have, and how to modify it correctly.

Try this, pull cap and rotor, open weights while lookikng at the center plate and how the weight flats move the center through the curvature. The whole process should move smoothly and fully all through the weight travel. A cam that allows over advancing will advacne nicely, then stop advancing for a few degrees, then have the tips of the weight flats push the cam plate further. The end movement will come after the weights stop the plate, then start the movement again, very fast right at the end of the weight movement.

That scenario is the one where the curve is OK for a dist and engine that don't rev past the rpm the weights stop the plate, and don't go fast enough for them to start the movement of the plate again.

Send me a pic if you would, please.

 

Dave here are two pics of the top of the dis. I hope this will tell you what you need to know.

 

Here is the other one