Howdy Everyone,

I just picked up a rebuilt 391 long block from an engine shop. As I was bolting up the fan/water pump pulley I noticed that either: the the main crank pulley is sucked in too far, or the water pump pulley is too far out. I'm about 1/4" out of alignment, which is fairly obnoxious. Furthermore, I have a spare engine so I tried exchanging both pulleys, but the misalignment remained. Perhaps this is normal? I didn't notice it when I pulled the engine out, though I wasn't looking either. Is there a spacer that sits between the end of the crank snout and the back of the pulley? There is a thin tin bushing for the timing gear cover seal that is pressed onto the crank pulley that seemed to line up accurately when I drove the pulley onto the crank. Also, for your diagnosis, the timing needle is hanging 1/8" over the crank dampener. The alternator pulley seems to be aligned best with the crank rather than the water pump.

Also, just in case anyone knows, there is a 5/16" threaded hole in the side of my distributor about half way down the wide part of the metal body, directly beneath the number 2 electrode. Should this be plugged?

Thanks for your help,
Kevin

 

That's weird... any chance the timing gear is too thin somehow? there should be a "slinger" in front of the timing gear, but that's not 1/4" thick, more like 1/32".

 

Yeah it does seem weird. I assume the "oil slinger" is the big offset washer that butts up against the timing gear?

 

I'm just going to make a spacer and stick it between the crank snout and the pulley. If this is idotic please let me know...

 

Yes, that's the one.

I would be VERY reluctant to make a spacer just for this.

 

This problem comes up once in a while. The fan hub is a press fit on the shaft of the pump and can be moved to align pulleys. I've gotten rebuilt pumps with this problem and adjusted the pulley hub to suit. Also they also make hub shims to align belts.

Have A good Day------------ Hotwrench