C2 Big Block Water Pump

[John R.]

On my way home this afternoon I heard a loud rattle from the front of my 67 big block. Upon investigation, it sounded like a marble in the water pump. The sound continues for about five seconds after the engine is shut off and sounds very much like the steel ball on a roulette wheel. Is it the water pump impeller or a piece of it? The engine was running a little warm but not unusually so for our 80 degree Phoenix weather. I'd really appreciate some advice before I tear down the front of the engine.

[george romano]

Re: C2 Big Block Water Pump

Also check the fan clutch, as well as the fan belts. It could also be an alternator bearing.

George

[John H.]

Re: C2 Big Block Water Pump

Is the engine "running-on" or "dieseling" after you shut the key off, or does the noise continue for five seconds after the engine has actually stopped rotating?

[John R.]

Re: C2 Big Block Water Pump

The sound continues after the engine stops rotating. It sounds like a good size ball bearing rotating in a circular enclosure. It is not the water pump, alternator or power steering as I have pulled all the belts in anticipation of of pulling the water pump. I thought that it might be the lower pulleys contacting the frame but they are stopped while the sound continues. I am relly stumped on this one. The engine is running great.

[george romano]

Re: C2 Big Block Water Pump

Is it an auto or 4 speed?

[John R.]

Re: C2 Big Block Water Pump

It's a four speed. Sound seems to be in the front of the engine.

[John R.]

Re: C2 Big Block Water Pump

With a fresh start this morning, the mystery has been solved. The problem is the balancer. It looks like I will have to remove the radiator and jack up the engine to fix it.

[John H.]

Re: C2 Big Block Water Pump

Is the balancer original, or is it one of those aftermarket "TCI Rattlers"? The "Rattler" is indeed full of steel shot/ball bearings, and at low rpm some of them sound like the inside of an outhouse in a hailstorm

[John R.]

Re: C2 Big Block Water Pump

The harmonic balancer was freewheeling like a hula hoop. I can't tell what was holding the outer ring to the center hub. It looks like it was a rubber sleeve but there is no sign of it anywhere. Guess I was lucky it didn't damage the timing chain cover.

[John H.]

Re: C2 Big Block Water Pump

John -

You're very lucky - usually they come apart and tear up everything forward of the timing cover, including the radiator, shroud, and the hood

[John R.]

Re: C2 Big Block Water Pump

And I thought the Corvette Gods were frowning on me! I had just rebuilt the carburetor, had John Pirkle rebuild the broken nose in the starter and installed a new battery when this happened. I don't know what I would have done if what you described had happened. Thanks for the post, John.