[Fot] TR4 crank endplay/thrust clearance

[M&M Hado]

Hi Tim,

Just some more food for thought.  No, it should NOT take a lot of force at
all to move the crank fore & aft.  I'm doing my 3B now and also a TR4 for a
friend at the same time and I can push the crank with my fingers alone on
one of the crank webs.  Do you have the front & rear bearing caps on as
well?  It sounds to me like your bearing bores are no longer lined up and
the crank journals are binding a bit in the bearings.

If this is the case with yours, a simple line bore at a machine shop will do
wonders.  What they do is take off a few thousands of an inch off the
bearing cap split lines which lowers them by that much (and makes then
slightly egg-shape), and then "line bore" through all three caps at the same
time with a long hone back to the original diameter.  They are now
concentric.  This is before putting in the liners, of course.  I think I
paid about $125 the last time I had it done.

Think about the crank sitting in the bearings with .002" clearance or so
and, if you really have a straight line, the crank will move VERY easily
because of that clearance.  It should not bind at all.

Also, I agree wholeheartedly about bumping the crank back and forth to "set"
the center cap to where the upper and lower halves of the thrust washer are
in the same plane.  The last bump should be forward, which is the normal
direction of thrust.  The rear thrust ring is the one that does all of the
work when you push on the clutch.

Good luck!

Mike Hado


-----Original Message-----
From: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net]On
Behalf Of Tim Murphy
Sent: Monday, March 08, 2010 10:06 PM
To: fot at autox.team.net
Cc: rpm724 at att.net; ryan.murphy at fdlco.wi.gov
Subject: [Fot] TR4 crank endplay/thrust clearance


Thanks again for the replies.  I loosened the center main block and "bumped"
the crank back and forth to center the block, as suggested.  Then retorqued
it and checked for clearance and endplay.  I still couldn't get much endplay
trying to pry the crank front and back so I "wedged" it front and back using
a big "tanker" screwdriver as the wedge between the center bearing block and
the crank.  That worked and I got .004 on the dial indicator and .005 with
feeler gauges for clearance.  Apparently it takes a bit of force to move the
crank back and forward but I'm sure the clutch pushes even harder than my
gently tapping the wedge in to move it.  At least my measurements now make
some sense.



Still learning!



Tim
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