I'll see if I can make this short. I've got some sort of sporadic tapping going on near the front of my engine. I'm almost positve that it's metal to metal. When the engine is cold it takes 15-20 seconds before it starts tapping and it's inconsistent. By inconsistent I mean it's not a perfect pattern that speeds up and slows down with the RPM's. If I remove the belt from the waterpump/crank/alternator then the tapping stops... Did it three times. Belt on =tapping, belt off = no tapping. The alternator is brand new, the water pump only has a few hundred miles on it from my last motor but sat in my garage for several months in between installs. I took the back of the waterpump off and can't see anything broken or loose. The crank pulley has a small dent in the outer ring from where I dropped it.... Could it be that?

Any suggestions would be appreciated.

Try and borrow a crank pulley from one of your friends or get one from a junkyard. You are going to have to go through a trial and error. If not sounds like an alternator problem. Try an old one. I had a toyota in the shop with a loud knocking/tapping sound coming from the alternator. Swapped it out and noise is gone. Let us know what happens.


Jay

Are the fins on the alt pully rubbing on the upper bracket?? To test the water pump just take the belt off & spin it, if its a bad bearing you'll feel it..

Scott

I'll second the water pump. I have one right now on my 62 327 Vette motor doing the same thing. The bearing in the nose of the pump is shot and it makes a sporadic popping noise when running.

water pump spins freely with no noise. The bearing feels nice and tight.

I can't see any marks where the fins would be hitting the alternator. I'm going to take the alternator back to the shop I bought it from and have them test it today...

sound like a coffee can with marbles in it? i had water pumps go before and that is what they did before they totally let go.

I had this problem once before. First I thought it was the p/s pump then the alternator. It turned out that the screws in the Crank pulley were loose. Tightened the screws the tapping went away. I also had a crank pulley itself start making noise where the two pulleys join together.

My money is on the water pump. They don't have to spit water out the hole to show they are bad. I have found that a sparatic noise from the front of the engine can easily be the pump especially if you remove the belt and it stops.

Tom

If you have a long screwdriver:

Put the metal end of the screwdriver to the suspected assecory, and you ear to the plastic handle of the screw driver. Do this with each assecory on the fan belt. It the tapping is coming out of the WP, PS, or ALT, you will here it clear as day through the scewdriver.