Randall Young wrote:
> ISTR hearing that the late box can be used on TR2-early 6 by using the later
> flywheel with it, but I'm not certain. It's possible the flywheel had to be
> drilled. TR2-4A would presumably also have to use the early starter, since
> the TR6 starter engages from the front instead of from the rear like later
> TR3-4A. Or, the TR6 starter can be used, but you may need to mill the
> starter mounting surface on the block to get the correct engagement.
No way to swap a TR-6 flywheel to a TR-3/4 without an awful lot of machining.
The
butt of '3/'4 crank is 4" diameter and the TR-6 is only 2 7/8" for both styles
of '6
flywheel - the early '6 flywheel being used on the TR-250 and TR-6 up to the
end of
1969. I run a late TR-6 gearbox in my '4 and the shorter input shaft engages
the
stock '4 pilot bush by just a tick over 1/4" (0.280" or about 9/32" actually).
This
seems somewhat minimal, but the car has covered just over 23,000 miles in the
last 3
years with this set-up without a problem. Also, the longer input shaft will
work fine
in the late TR-6, as there is quite a bit of counterbore in the end of the
crank for
clearance. I use a '4 gearbox with the thin flange and longer input as a
loaner when
doing rebuilds, etc. when we're having trouble locating the right parts, and
that 'box
seems to fit everything with no problem from '3's up to '76 TR-6. After this
discussion, I'm really curious about what mounting bracket I've got with that
as it's
always been a bolt in with no clearance problems.
If anyone is contemplating swapping a late gearbox to an early engine - it can
work,
but I suggest checking the amount of engagement by covering the end of the
inputshaft
with modeling clay and smearing the face of the pilot bush with oil, then bolt
the
trans into place without the clutch plate - unbolt again and measure how far
back the
clay was pushed away from the tip of the input.
Since there seems to be good evidence that the three syncro boxes are a little
shorter
than the four syncro units, there may be more or less clearance than what I've
measured depending on the combination of engine/flywheel/trans. If anyone is
seriously planning a swap where they feel this may be a problem, please contact
me.
We've got dozens of gearcases and blocks from all different years sitting
around. I
would be happy to check fit of a particular combo for any lister who's
interested.
Regards,
Brian Schlorff '61 TR-4 '64 TR-4 '72 TR-6 '79 Spit
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