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MG MGB Technical - Strange Noise

Hi,

I'm about 500 miles into a recently rebuilt engine on a 69 bgt and it has developed a strange new (high pitch or whirling) noise from the engine.

It started out intermittent but occurs all the time now. The noise is "rotational" in
nature (e.g. changes with RPM, but not speed). So I first thought of the belt, alternator, and water pump.

Last night I removed the belt to see if the noise went away: no difference!

Seems to be coming from the front of the engine but I can't be sure.

Could it be crank pulley/harmonic balancer? or maybe rubbing against the front seal in this area?

Any ideas (crazy or otherwise) welcome.


Bill

PS. Engine seems to run normal otherwise.
Bill Schoolfield

Did you rebuild your engine, yourself? Just wondering.

Did you check all the hoses for a vacuum or pressure leak?

Is the distributor lubed? Breaker cam lobes greased? Remove the rotor and put
several drops of light engine oil onto the screw head that is atop the rotor shaft
and wait a few minutes for it to seep down into the distributor bushings.

Since you've determined that it's not belt-driven related...and that the "whirling" is
mechanical in nature and coming from the front of the engine...

Camshaft walking forward and timing gear rubbing against the inside of the timing cover?
(could be a loose retaining plate). Is the timing cover straight? ...no dents or dings?

Timing chain tensioner goofed? Sometimes they forget to unlock the rubbing block
(using an Allen wrench) after they install it.

Oil feed to that area blocked? I think oil feeds through the chain tensioner body and then
onto the rubbing block to lube the chain and gears. If the tensioner, or the gasket, was installed
incorrectly, then soon the works there will run with inadequate lubrication.

These ideas may seem far-fetched, but then these cars are just full of pleasant surprises...no?
Daniel Wong

Daniel,

Yes, I did the rebuild. My first and so I have doubted myself all along. So far I've
seemed to either have done everything right or the mistakes were easily addressed!

I haven't done anything else to diagnose this issue yet but will investigate using
your suggestions.

Timing cover plate is normal but maybe it is loose.

The noise is pretty loud. Listening down the
oil filler, I did not hear the noise as much
so I think it's down low....


Bill
Bill Schoolfield

Did you put a spot of grease on the pilot shaft bushing ?????
Dauntless

Are your radiator shroud bolts tight? Is the radiator touching the chassis at the front?
David

Dauntless,

Had to think back on this one, but I seem to
recall sticking my finger in there to grease
it up but I did not replace the bushing.

David,

It doesn't appear to be the radiator. It's
secure and I even ran briefly without a
belt so the fan wasn't moving.

I think I'm going to take the timing cover
off and have a look around....


Bill
Bill Schoolfield

This thread was discussed between 18/12/2002 and 19/12/2002

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.