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Re: Friend need help to diagnosis on TR4a noise

To: "Ronnie Babbitt" <rbtr3a@cox.net>, Cameron Leonard <Cameron.Leonard@MSMERI.ANG.AF.MIL>
Subject: Re: Friend need help to diagnosis on TR4a noise
Date: Fri, 25 Jun 2004 08:37:27 -0400
Cc: "Triumphs" <triumphs@autox.team.net> i5PCdxOJ016572
Message text written by "Ronnie Babbitt"
>            The problem noise I'm having with my TR-4A is what I would
describe as an amplified or extremely loud valve tap.   The only time I
have this problem is when the clutch is depressed, and it seems to be
worse the hotter the engine gets.  It's not noticeable when I first
start her up before the engine gets warm or after running at highway
speeds for a little while.  But, once she's hot and running around town
from light to light the noise gets louder and louder.  If I go through a
drive through, it gets really bad.  I don't really understand the engine
temp factor, but the noise is definitely related to engine speed.  My
guess is that it's probably the fulcrum pin between the clutch fork and
the shaft, which I replaced last time.  When I last had the gearbox out,
I rotated the pins on the clutch fork which engage the sleeve for the
release bearing 180 degrees so that there was no wear on the part of the
pins which contact the release bearing sleeve.  I'm now wondering if I
should have only rotated those pins 90 degrees, and that my noise is a
vibration caused by the gap on the back side of those clutch fork pins.
Or maybe I should just replace everything.  What do you think?

 
Thanks Cameron 
<

Cameron, DO NOT DRIVE THE CAR UNTIL YOU CHECK CRANKSHAFT END FLOAT.  The
symptom sounds like you may have lost a thrust washer.  To check endfloat
get a large screwdrive or crowbar and push the front crankshaft pully in
toward the engine pushing the crank up tight against the forward thrust
washers, set a dial indicator to zero then push in the clutch.  The clutch
will force the crankshaft forward against the rear thrust washer.  If it is
there you will get a reading on the order of .007 to .015.  If it s missing
the reading may be closer to .060. If it is missing it may be too late to
save the crank. 

If the reading is on the order of .007 to .015 then that is not the problem
(although a .015 reading indicates it is time to consider changing the
thrust washers) and the next thing I would check is the clutch throwout
bearing.  But a failure here is less traumatic.

Dave Massey
57 TR3
71 TR6
80 TR8





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