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MG MGA - Flywheel

When rebuilding a 1600 block to replace my blown 1500 I utilized a 3 main flywheel I had laying around. I am now experiencing a slight squealing from my thro out bearing while just sitting there. It was a Moss product that was installed about a year ago in my first engine. It only had 2000 miles on it so I reused it on the 1600 rebuilt engine. When pressed it's fine. Is it going bad? Could the new flywheel behaving an efect on it?

WMR Bill

Bill,
Are you using a carbon or roller bearing throwout bearing? If using a carbon unit, there is a simple external modification that goes under the slave cylinder to move the throwout bearing off the flywheel when not in use. It is called a stop kit (mgbmga.com/tech/mgb2.htm) dated 1/26/02. This might help. Have a good day!

John
John Progess

WMR,
I had this same problem, a slight squeal that disappeared when I depressed the clutch pedal. I put up with it for a couple of years. Last summer, however, I needed to replace my transmission. In the process I switched to the lightened MGB flywheel and clutch assembly. Now no more noise.
My guess is that it is the throwout bearing, but you may also need to have the flywheel resurfaced if you didn't do that last time around.
I hope this helps, as that squealing noise was extremely annoying.
James
James Hurm

Thanks Guy's, I did have the flywheel cleaned up and cut. It is the carbon one that I am using and it is already put together. John thanks and I will investegate the kit! Can I presume that there is nothing wrong then with the bearing and it's just an inconvience noise I may have to put up with?
WMR Bill

WMR,
I drove my car like that for a couple of years. When I replaced everything last summer, the throwout bearing (carbon)still had plenty material left on it. I had a problem with my transmission and used that excuse as an opportunity to upgrade and replace everything.
Others can weigh in here, but I thought it was too much of a hassle to fix in the absence of no other issues. It was still annoying though...
James
James Hurm

I am curious...why would a carbon throwout bearing squeal? I've never known them to make any noise at all. I would be more suspicious of the pressure plate(clutch cover)...the disc that the throwout bearing rides against...some type of vibration. Or, perhaps, even the input shaft bearing on the transmission.
Cheers,
GTF
G T Foster

If the pivot bushing in the clutch release arm is worn it could allow the top end of the release arm and release bearing to move off center enough for the release bearing to drag on the gearbox input shaft. This could cause some noise, possibly high frequency chatter or mild squealing sound that could go away with slight clutch pressure.

You might check from underneath to see if the release arm will wiggle sideways substantially, and if this would make any difference in the noise when the engine is running with transmission in neutral and clutch at rest.

If moving the release arm slightly with your fingers when engine is running has no effect on the noise, start thinking and looking for something other than the release bearing, like maybe the gearbox input bearing. Also check to be sure the slave cylinder mounting bolts are not too long and touching the clutch cover inside the bell housing.

Some parts of the starter Bendix drive might chatter or squeal from a harmonic vibration (while otherwise motionless) at a specific engine speed. Such harmonic vibration can be very sensitive to a small change of frequency (engine speed). Just touching the clutch pedal might slow the engine speed and vibration frequency enough to go out of that harmonic frequency range and stop the noise.

The same harmonic vibration issue might apply to any sheet metal part attached to engine or gearbox, like a cracked exhaust pipe brace on the bell housing bolt (fairly common), or the carburetor heat shield. You need to move around while listening under there to identify the exact location of the origin of the noise. A mechanic's stethoscope might help.

It could be worth more effort to identify the exact cause of the noise before pulling the engine out without knowing why you're doing it. Always do the diagnostic work first before throwing your labor time or money at it on a guess or speculation.
Barney Gaylord

Like barney said, it could be something other than the throwout bearing. I currently have a bad input shaft bearing, and it makes noise while the clutch is disengaged; when depressed the noise goes away. The noise is not a squeal but more of a rumble, but a bad bearing could squeal also.

mark
Mark J Michalak

This thread was discussed between 13/01/2009 and 15/01/2009

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