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Diagnosing engine grinding/growling noise, water pump questions TR4A

To: <triumphs@autox.team.net>
Subject: Diagnosing engine grinding/growling noise, water pump questions TR4A
From: "Glen Sapilewski" <glen@step.Stanford.EDU>
Date: Fri, 19 Oct 2001 11:25:04 -0700
Hello Folks,

    Our '66 TR4A engine is running quite well, but has recently
started making some very unpleasant sounds.  The nature and location
of the sounds make us a bit worried about major disasters (engine bearings,
etc.)
so we have stop driving the car.  :(

     Summary of questions:
      - Is it possible to run the engine with the water pump disconnected
(fan belt
        removed) for ANY length of time without "frying" the engine????
      - How much 'play' should there be in the water-pump pulley?
      - Any method to test water pump insitu?

Thanks!
   Glen & Alison

   1966 TR4A-IRS in family since '66
   Bay Area, California USA

-------------------------------------------------------------------------

--- Details  ---
    Describing sounds is very difficult in text ....
The sound is a growling / grinding noise which appears to be coming from the
the front of the engine.  It is relatively constant, but can take a minute
or two to come up to full volume after startup.  It's not really a specific
frequency.
   I used the ole' "broomstick trick" to try to isolate the sound source.  I
compared
the relative "volume" from the generator, water-pump, & block and the noise
is more pronounced on the water pump.  I know sounds sources can be very
devious.
   I removed the fan-belt and hand-turned the generator and the water pump
pulleys.
The generator turned very smoothly and actually a little easier than I
expected.
The water pump turned reasonably smoothly, but the pulley had much more
side-to-side play than I thought acceptable.  When I tried to rock the
pulley on its
shaft, it tilted about 0.75mm (1/32").   Is this normal???
    I tried experimenting with the belt tension, it seemed to have an effect
but wasn't repeatible enough to make any conclusions.  Right now the
generator adjustment
is at its maximum extent, resulting in a belt deflection of 1/2 to 3/4".
(Before
today it was deflecting about 1" at the water-pump to fan-pulley run).   The
belt
might be stretched due to the inability to tension further, but it looks in
good condition.
  If it's safe we'd like to run the engine with the water pump disconnected
(fan belt
removed) for a short period to see if the sound disappears.  A wacky idea,
but maybe we could use a garden hose to force water through the engine
during this test?
  I wouldn't completely eliminate the chance that a portion of the sound
could be due to coolant gurgling and cavitating.

Car state:
  Note the car doesn't have any overheating problems, so at least the water
pump
seems to be working.  Oil pressure seem to be acceptable.

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