Let's not forget, we're all using transmission cases that were built at
least 30 years ago, and probably have some 75,000+ road miles before we got
ahold of them. I cracked the case on my TR3A last year and I'm no where
near 150BHP. The system described below sounds like a worthy prevention
device and not too difficult to create. Thanks for the input.
Bob Kramer
rgk@flash.net
----------
> From: R. KASTNER <kaskas@earthlink.net>
> To: DLMAssoc@AOL.COM
> Cc: fot@autox.team.net
> Subject: Re: The Good, the Bad and the Ugly
> Date: Thursday, March 25, 1999 12:15 PM
>
> Indeed we had problems with the transmission/bellhousing cracking, but,
> remember we were using the engine and CAR at the highest amount of
> usage, I.E. high revs for at least thirty to forty-five minute races.
> This is 6500 revs for a good long time.As you have surmised there is a
> method of aiding the situation,the mounts, and indeed this does help.
> We did make mounts that supported the junction of the engine to the
> transmission. We used small rubber engine mounts with long strap iron
> brackets that came down to the bell housing bolts and the mounts were on
> each side of the battery box. This did make a positive difference. But,
> we never had this problem until we started making real power, that is
> above 150 BHP. We broke at least ten or fifteen of the gearbox housings
> until we made the hangers with rubber mounts . We still cracked the
> casings , but the whole business at least held togeather for the length
> of the event. At one time I also welded side plates onto the the gearbox
> case but they also cracked. This was probably because they were very
> soft after being annealed by the welding. I think I might have worried a
> lot of people without cause for most will probably NEVER use the cars
> and engines as hard as we did at that time. I'll try to answer any
> comments on this.
>
>
> DLMAssoc@aol.com wrote:
>
> > FOTers:
> >
> > The discussion of bell housing breakage in early TR4s is very timely
for me...
> > I'm ready to put one in a car but have stopped till I figure out what
to do to
> > minimize the possibility of cracking.
> >
> > Kas has explained about the "gong" device they used to use, and Nick
(at least
> > I think it was Nick) has recommended welding braces from the bell
housing to
> > the tranny. Another "old" TR racer I talked to today said the problem
was
> > probably caused by the combination of engine and tranny flexing, since
they
> > were supported only by the front motor mounts and the tranny mount at
the
> > rear. Without support in the middle, the flexing would break the bell
> > housing. He said he used to install motor mounts at the rear of the
engine to
> > eliminate the flex. This seems to make sense, but I wonder if anyone
else has
> > done this or is there some reason this wouldn't take care of it.
> >
> > Thanks...
> > Don Marshall
|