Here's the deal on Spit/GT-6 trannys from my mouth,
The GT-6 box is not stronger than the Spit box, and is actually
weaker than the 1500 Single Rail tranny. The reason for this is the size
of the pocket bearing.
The updated (17 tooth?) TR-7 reverse gear is a good replacement for the
standard one, but you need to interchange the laygears as well.
The GT-6 box will bolt up to a Spit engine, you just need to change
the backing plate, but the input shaft on the GT-6 trans sticks out ahead
of the bellhousing, whereas the spit resides just inside the
bellhousing. Would this be a problem? Probably. I've never had
occasion to think of putting a GT-6 box behind anything except my
junkpile, because that's what they are: Junk. I've got a GT-6 + D
type overdrive in my Spit now, but it is working on borrowed time.
Both GT-6 and Spit use the same pilot bushing, Triumph #105143.
The GT-6 box, by virtue of its starter placement, doesn't exactly
fit into the Spit body. You need to cut away at the firewall sheet
metal, then fit a GT-6 tunnel cover (and carpet piece), or modify your
current tunnel cover with fibreglass (suck).
The reason GT-6's have such close gearing in 3-4 is that they had to
make 1st so tall in order for the box to be any use at all. They knew that
if they used the ultra-low Spit 1st gear ratio with the improved torque of
the GT-6 2.0 litre, they might as well blank the gear off completely and have
drivers start in second, just like in Austin Healeys. But making a new 1st
gear which was so much taller necessitated making 2nd gear taller, and third
taller as well. Before you knew it, 4th gear became nearly useless since it
was fixed at 1:1 by design and could go no higher.
In fact, 3rd + OD is a taller ratio than 4th without OD. What an
awful tranny the GT-6 is burdened with.
One interesting thing, the Triumph 2000 sedan used the 2.0 litre,
but it also used the TR-6 tranny. So one way to solve your dilemma would
be to find an old TR-2000, hope the lay-bearing surface is good and round
(TR-2-6 owners know what I mean) and use that tranny. Of course you'll
have to make a mount, but tranny mounts are easy, since it's a piece of
cake to design them to ensure that they see no tension.
Greg
Greg Meboe meboe@wsunix.wsu.edu
Web site>> http://www.scs.wsu.edu/~meboe
Dept. of Mechanical and Materials Engineering
Washington State University, Pullman, Wa.
'85 XJ-12 H.E. (daily) '67 Spit-6 '74 TR-6
|