460 distributor gear failure

good2go · #1 (**permalink**) 09-30-2001, 08:17 PM

I went for a cruise on Sat and was about 50 miles from home when I left a red light shifted up to third when I had a loud bang, backfire, and everything went dead. I checked for spark and found none. Pulled the distributor and sure enough three teeth were gone the remaining ones are worn at a angle whick looks like they are not making full contact with the cam gear.

I looked into the distrb hole and saw what looks like a circle worn into the block where the face of the gear rides.

A person brought down a new distrb and we got the car home but I wonder what caused the wear and how do you solve the problem. Maybe a shim to raise the gear to the correct height. What would have caused the wear in the first place?

It was an MSD billit distrb in a 460 crate motor.

Any help would be appreciated.

Thanks

Tom Wells · #2 (**permalink**) 10-01-2001, 05:19 AM

on the material the camshaft itself is made of.

Most of the roller cams are steel, so a steel or aluminum-bronze distributor gear must be used.

A "normal" cam, usually cast iron, uses a cast iron distributor gear.

If you use the wrong mixture of gear/cam materials you will get the result you experienced. For example, a cast iron distributor gear used with a steel cam spells disaster.

My 514 crate motor came with a steel roller cam and a steel gear on the end of the distributor.

Hope this helps.

Tom

good2go · #3 (**permalink**) 10-01-2001, 08:09 PM

Thanks for the info. It was a stock cast iron cam that came with the crate motor with a cast gear. Thanks for the input.

Dave #88

aeroace · #4 (**permalink**) 10-05-2001, 09:57 AM

If material compatability is not the issue, you'll need to check a few other things. Is the dist. shaft straight and free to rotate easily? Check the height of the gear relative to the boss on the housing where the dist. is bolted to the intake. Is the dist. hole in the intake centered over the oil pump drive rod or is it off center causing a side load? I've seen MSD billet dist's that didn't have the hexagonal oil pump drive rod hole broached deep enough into the shaft of the distributor. The dist. bottoms out on the oil pump rod before the housing rests on the intake. A difference of .050" and the oil pump becomes heavily preloaded by the distributor, becomes very hard to turn, and the distributor gear wears out in no time. A close inspection of the wasted parts is your best clue what went wrong in the first place.