ksands18
New member
In my quest to tackle poor mileage (about 13 to 15mpg) and weak acceleration, I've upgraded a host of components from pertronix to flame thrower coil to a new (professionally rebuilt) autolite carburetor itself. Still no noticeable improvement.
Timing is set as recommended at 12 dbtdc (as per C4 auto trans specs) and I just happened to hit the throttle with the timing light still pointed at it and it's only advancing 4 or 5 degrees more. Is this all the advance it is supposed to have with a load a matic distributor? I've read from others online that their advance goes WAY farther than that, making me wonder if that's where my problem has been all along.
My vacuum advance unit is brand new and I can hold a vacuum to it without any leakdown. The vacuum from the advance port on the carb shows zero at idle (as it is supposed to) and up to 5 inches at open throttle....does that seem too low? When tuning the carb with the gauge hooked up to the port on the intake below the carb, I get a steady 20 in of vacuum at idle.
The only other thing I can think of is maybe an issue with the distributor plate and/or springs (maybe they're installed wrong?....see pic below). If I suck on the carb end of the advance vacuum line, the distributor plate appears to move freely and quite a bit more than what I would estimate 4 or 5 degrees would be.
Any ideas what could be wrong here? Is there just not enough vacuum coming from the carb to get the right amount of advance and if so is there any remedy for this?
Timing is set as recommended at 12 dbtdc (as per C4 auto trans specs) and I just happened to hit the throttle with the timing light still pointed at it and it's only advancing 4 or 5 degrees more. Is this all the advance it is supposed to have with a load a matic distributor? I've read from others online that their advance goes WAY farther than that, making me wonder if that's where my problem has been all along.
My vacuum advance unit is brand new and I can hold a vacuum to it without any leakdown. The vacuum from the advance port on the carb shows zero at idle (as it is supposed to) and up to 5 inches at open throttle....does that seem too low? When tuning the carb with the gauge hooked up to the port on the intake below the carb, I get a steady 20 in of vacuum at idle.
The only other thing I can think of is maybe an issue with the distributor plate and/or springs (maybe they're installed wrong?....see pic below). If I suck on the carb end of the advance vacuum line, the distributor plate appears to move freely and quite a bit more than what I would estimate 4 or 5 degrees would be.
Any ideas what could be wrong here? Is there just not enough vacuum coming from the carb to get the right amount of advance and if so is there any remedy for this?