At 01:05 AM 9/11/02 -0400, cl4rk2@worldnet.att.net wrote:
>.... '69 MGB/GT. Before car is up to normal operating temp, it will
>sometimes violently shake when I release the clutch pedal in 1st
>gear. What exactly is causing this clutch shudder?
Could any of a number of things. If you happen to live a good life, and
you get really REALLY lucky, maybe it's just bad engine mounts. But I
doubt it.
My first suspect would be a worn spigot bushing in the tail end of the
crankshaft allowing the gearbox input shaft and clutch disk to wobble about
off center. Cure would be replacement of the spiggot bushing. Loose
splines in the clutch disk (or on the input shaft) can aggrevate this
situation. A glazed surface on the clutch disk can sometimes do it. For
either case the cure would be replacement of the clutch disk. A much less
likely but possible item would be a carburized surface on the flywheel or
pressure plate cause by repeated exposure to high temperatures (slipping
clutch, high torque engine, leaded left foot). Cure for this is to reface
the flywheel and/or replace the pressure plate.
While any one of these things could be causing the problem, it is much more
likely a combination of more than one item. The good news is that fixing
just one of the ailments is likely to stop the shaking. The bad news is
that you have to part the engine from the gearbox to fix any of them.
> Will I cause harm by continuing to drive in this condition?
Well, probably not immediately. But being bad enough for long enough,
severe shaking is bound to eventually cause some problem in the
drivetrain. This might be wear on the clutch splines, strange failure mode
for the clutch release bearing or the release arm, broken gear teeth in the
transmission or differential, worn thrust washers in the differential,
failed u-joints in the propshaft, damage to various ball bearings. Failed
engine mounts may lead to cascading damage to engine accessories, radiator,
hoses, linkages, exhaust pipe, exhaust hangers. And then the remote
possibility that your life may be on the line if something serious breaks
while traveling at speed.
This is definitely not good behavior for an MG. It isn't just
irritating. It has the potential to become a serioius inconvenience and
expense. In other words, you really ought to fix it pretty soon.
Barney Gaylord
1958 MGA with an atittude
http://www.ntsource.com/~barneymg
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