Thanks for a very good perspective and an excellent piece of written
engineering description.
It brings up the question of putting the V8 in so that the transmission
comes along with it. Have you any perspective on that?
Roger
----- Original Message -----
From: <mporter@zianet.com>
To: "Roger Langley" <galahad@uslink.net>
Sent: Monday, October 14, 2002 4:38 PM
Subject: Re: TR7 5 speed for a GT6?
> Roger Langley writes:
>
> > How hard is it to adapt the TR7 five speed transmission to a GT6?
>
> Roger, I have one sitting in storage for that purpose, whenever I can find
> time to make the adapters, etc. I'll tell you roughly what I've determined
> thus far.
>
> The bellhousing is the biggest problem, because the starter is on the
upper
> left, rather than down low on the right in the GT6. This requires the
> construction of a new rear engine plate. I don't think the standard
starter
> will clear the distributor pedestal, but one of the gear reduction
starters
> might. The fuel pump has to be removed, a block-off plate installed and an
> electric fuel pump fitted.
>
> The rear trans mount has to be modified, but this is fairly simple
> fabrication. The transmission is a good deal taller than the GT6 trans, so
a
> new tunnel cover must be fabricated. Shift position is a bit more rearward
> (which suits me fine, since at 6'4", I've already got the seat far back
and
> tilted backwards as far as it will go). The driveshaft flanges are nearly
> identical in size and shape, but the bolt pattern is different. At this
> point, I haven't checked to see if the same u-joint is used in the TR7, so
> that yoke flanges can be swapped.
>
> The overall length of the transmissions is very close, so I don't know yet
> about driveshaft shortening. There may be enough in the slip joint to
> accommodate the difference without driveability problems.
>
> The clutch arrangement, compared to the above, is pretty straightforward.
> The 5-speed uses a different spline set than the GT6, so a TR7 driven disc
> must be used. The good news is that it is the same diameter as a TR6
clutch,
> so I think all that's necessary is to have the existing flywheel ground to
> accept the larger disc and have it redrilled for a TR6 clutch cover. There
> is probably some small shimming of the throwout bearing receiver required,
> but maybe not. The stub end of the input shaft is larger than the GT6,
but,
> if I recall correctly, a bushing to fit can be made without alteration of
> the crankshaft. Just a matter of making a bushing to fit both and
installing
> that.
>
> That's about what I have for now. Haven't done any actual fitment yet, so
I
> don't know if there would be any small firewall modifications required to
> accommodate the bellhousing starter bulge. I suspect that fit will be
quite
> close, and might require a little relief so the bellhousing doesn't bind
on
> the body when the engine moves on torque.
>
> Hope that helps.
>
> Cheers.
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