Did a 1969 Z/28 Distributor today for a friend on my distributor machine. He wanted it brought back to stock specifications and not a faster curve, which most people end up doing. I ended up rebuilding the distributor for the guy, installed new shims and a new limiter bushing.
Specs call for Zero at idle, 11 degrees at 2200 RPM and 16 degrees at 4400 RPM. Since the distributor turns at half of the engine speed, you divide the engine RPM in half and this is what he distributor machine tach shows.
When you look at the pictures you'll see the arrow pointing at the 360/zero mark in the first one, 10 degrees in the second pic and almost 16 degrees in the 3rd pic. The limiter bushing is what limits the total advance, so that number is fixed. The springs control how fast the advance changes.
The tach is the upper left corner and right below that is the dwell meter, which is right at 30 degrees in all the pics. You can expand the pics so you can see the readings pretty well.....
I wasn't able to check the vacuum advance unit because the vacuum system must have a leak in one of the hoses. I haven't used that in quite a while because all of my race cars have a locked distributor and don't use a vacuum advance unit. All it needs are the hoses replaced, which is pretty simple, but it is snowing today and I am not going to the auto parts store today to get some 1/8" hose...
I haven't use my machine since I did Krazybones Dist at least 5 years ago. At least I remembered how to use it
Gary
Specs call for Zero at idle, 11 degrees at 2200 RPM and 16 degrees at 4400 RPM. Since the distributor turns at half of the engine speed, you divide the engine RPM in half and this is what he distributor machine tach shows.
When you look at the pictures you'll see the arrow pointing at the 360/zero mark in the first one, 10 degrees in the second pic and almost 16 degrees in the 3rd pic. The limiter bushing is what limits the total advance, so that number is fixed. The springs control how fast the advance changes.
The tach is the upper left corner and right below that is the dwell meter, which is right at 30 degrees in all the pics. You can expand the pics so you can see the readings pretty well.....
I wasn't able to check the vacuum advance unit because the vacuum system must have a leak in one of the hoses. I haven't used that in quite a while because all of my race cars have a locked distributor and don't use a vacuum advance unit. All it needs are the hoses replaced, which is pretty simple, but it is snowing today and I am not going to the auto parts store today to get some 1/8" hose...
I haven't use my machine since I did Krazybones Dist at least 5 years ago. At least I remembered how to use it
Gary
