671TI noise

[nick]

I just finished complete cooling system service, hose replacement and commissioning of the 671TI's in our 37. On startup of the starboard engine I hear a slight whine type noise at the front of the engine around the crank pulley. Seems to catch up with engine speed but not directly proportional to engine rpm. the nosie is not heard at the port engine. We disconnected the alternator belt, same noise. I was wondering if it is the viscous vibration damper or the oil pump gears just inside the front cover of the engine. I am leaning on putting in a new "rebuilt" viscous damper.

Any thoughts on the noise/repair???

Nick

[Genesis]

Whines are usually caused by either bearings or gears.

I'd suspect the circulation pump (fresh water), but if its not leaking, I'm not sure I'd do anything about it right now, other than watch it carefully. Detroits make noises that are extremely hard to isolate at times..... and aren't always indicative of a problem.

[Nick]

Thanks!

Does the dampener make any noise when it fails?ometimes it sounds like cavitation. No leak or noise evident at the water pump.

NAA

[Genesis]

Dampers are kinda strange...... their failures are not always obvious. The usual advice is to change them when you do an overhaul, "just in case."

Cavitation? Ok, that MIGHT be the damper....

[Nick]

Thanks!

I don't have the history on the overhaul and will replace the damper assuming it is the source of the noise. The local Detroit rep indicated that I could get a rebuilt damper at a reasonable price. (if there is such a thing).

Nick

[osprey]

As always, if after maintenance you discover something new. go back to the last things you touch. You mentioned cooling system hose replacement. could the whine be air in system, plugged rad cap, hose sucking air . Only guessing, good luck, let us know what you find, most don't. P

[dsharp]

After 18 years he probably forgot the noise.