At 09:50 PM 1/26/99 -0500, M. W. Jordan, Jr. wrote:
>.... This evening, I started it up in the garage, and there was the noise
again at idle. .... more noticeable from the front of the car than from
the rear. I did notice that when I shut the engine off, the ringing
continued for just a second as the engine came to rest.
>....
With the engine running, depress the clutch. If the noise goes away it
would be something inside the tranny, or possiby the clutch release bearing
being a little loose on the release arm, or the thrust ring in the center
of the pressure plate. My guess is none of the above, and I hope I'm
right, because fixing these items requires pulling the engine (again).
One common cause of a light rattle that can sound like a ringing is a loose
fan on the front of the generator, usually caused by a slightly loose nut
holding the generator pulley. Either the fan rattles on the shaft, or the
fan touches the front plate of the generator. Occasionally the rivets
holding the generator pulley together work loose and the pulley parts can
rattle, even when the retaining nut is tight. Similarly, the rivets in the
crankshaft pulley can get loose, and the crankshaft pulley can rattle even
when the retaining nut is tight. To check these pulleys, slack off the
belt tension first, then check to see if anything on or around the pulley
wiggles. Also check to see if the water pump pully or shaft or fan blade
can wiggle a little.
If nothing turns up at any of these points, you can run a cool engine for a
minute with the fan belt off without any ill affects to check for the noise
without any of the front accessories turning.
Also check small brackets, like the prop rod retaining clip, the bonnet
latch parts, and the fan guard on the top of the raditor. If you put your
finger on one of these bits while it's rattling and the noise stops, you've
found the culprit.
Another small part that can vibrate at high frequency is the wire wrapped
tube on the temperature sender unit, running between the cylinder head and
the inner fender. This will usually be about 12 to 18 inches of length
with at least one loop in it for flexibility.
Check the push/pull cables for the choke, throttle, starter, heater water
valve, and heater damper on the bottom of the heater box. Also check the
heat shield at the carburetors. And there should be (may be) the original
throttle cable return spring on a bracket below the rear carb, and a little
cable holding the oil filler cap. Any of these parts may resonate or
rattle against other parts.
Okay, what else have I missed?
Barney Gaylord
1958 MGA with an attitude (and not many rattles left)
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