Re: Starter drag?

Posted by Mike On 2011/1/20 19:22:56

I went back out tonight with a plan to rebuild the early pump.

But then i found the kit doesn't fit EITHER pump.

So i started at the basics. I took the mighty vac and found it took very little vacuum to instantly get fuel from the line. No Problem there.

Rolled both motors around so the cam lobe was pushing the pump out and compared, both being pushed out about 3/4" from the block without forcing it in. (Must have had the lobe on the opposite side for other installs, never felt resistance.)

Took both pumps apart. Had trouble with the new one and set it aside.

Took the early apart, and it was very clean and diaphragms very good condition with some writing on them. Had to be rebuilt at some point, maybe 10-15 years ago when they did the first restore.

Worked it on the bench and easily putting out 5-6 psi bench testing. Put it back on the car (no gaskets or spacer, test fit.)

Rolled it over, little bit of air coming out of vacuum pump exhaust, maybe 1 psi pressure, very little on the fuel pump.

Thought for a minute and put some fuel in the carb bowl, then hooked the fuel line up to the fuel pump inlet.

Fired the motor, instantly spraying fuel everywhere. EVERYWHERE.

I've lost about 2 gallons of fuel over the last couple days to these experiments. Ugh. Love the lemon flavored simple green.

My theory is that both of these pumps are weak, but it didn't show because there was always fuel in the carb bowl to fire the motor, which cranked the cam over fast enough once it fired to start pumping.

I think that my real problem wasn't that the fuel pump wasn't pumping...it wasn't pumping enough at a slow roll over rate to get fuel moving in a completely dry system.

I will likely exchange the fuel pump that's not in pieces even though it is working, for the piece of mind of a new fuel/vacuum pump that will likely move some fuel, even if it's just the starter rolling things over.

In the meantime, i'll finish buttoning up the tranny linkage and getting that filled the rest of the way and hooking the new coolers up to it so i can let it run for more than a split second without worrying i'm going to hurt something back there.

Thank you ALL for the advice, I've certainly learned more about the fuel/vacuum system on this car than I intended to. If all goes well and you guys make it to Warren, i'll buy a round of beer!