I used the valve spring washers shims with good results. I also carried the
pressure in the 600 to 700 range. On another O.D. I drilled and taped the
cover and fitted a small seal and a bolt ao that I could adjust the pressure
from the outside RUNNING. Worked for a while but the cover would not take
the pressure cand cracked.. This might be a good idea now using a milled
7075 T-6 aluminum or steel plate. My cars were always looked at so closely I
couldn't get away with changing the part.
----- Original Message -----
From: Henry Frye <thefryes@iconn.net>
To: <fot@autox.team.net>
Sent: Thursday, April 27, 2000 4:51 AM
Subject: Overdrive Prep
> Greetings ,
>
> One of the many things I am doing before the next time out is an overdrive
> gearbox. The gearbox I ran at Savannah is toast. I've given the project to
> a local guy who raced a bit here in New England in the '70's.
>
> We are deleting the 4 inner springs and opening up the operating valve
hole
> as was suggested here a while back. This is what my guy has done in the
> past and he was very happy with the results.
>
> To increase the operating pressure, Bill Emery wrote this back in
January:
>
> >2) Shim the accumulator spring to increase the operating pressure from
420
> >psi to 650 psi. They started with an 0.080" thick shop washer and then
> >worked with shim washers. I bought a 1000 psi gage and started making
up an
> >adapter for testing the pressure, but never got to the stage of testing
this
> >pressure while running the car on jack stands (maybe there are better
> ways of
> >testing). I just installed the 0.080" washer and went with it.
>
> On the subject of accumulators, there are two varieties fitted to the TR
> range, the early type uses a large piston that sits directly in the bore
in
> the OD case. This early type uses two springs, an inner and an outer.
Then,
> the later type uses a smaller accumulator piston that has a separate
> housing. This housing fits into the same bore in the OD case as the
earlier
> large piston. This later type uses only one spring and a distance piece.
> This is a neat arrangement because you can replace the housing after it
> becomes scored from your OD circulating swarf.
>
> The guy rebuilding my box says the earlier arrangement is the way to go,
> the bigger piston operating at high pressure will push more oil faster for
> better engagement. I'm sort of buying that.
>
> The box we are working with has the early variety with the big piston and
> two springs. Before teardown we bench tested it and it made a wimpy 340
> lbs. of pressure. It did engage and disengage fine on the bench, by the
way.
>
> Instead of shimming the accumulator spring, what my guy always did was
> source a different inner spring for the accumulator. The early type, that
> is. He knows it was from a Healey, but can't remember which one. Does this
> ring a bell with anyone? Does the shimming procedure Bill discusses apply
> here? Do we shim both springs? They aren't going to bind? Anyone know
where
> I can get some new accumulator springs?
>
> As always, thanks again for all the help.
> Henry Frye thefryes@iconn.net
> http://members.iconn.net/~thefryes/amici.html
> TR4 suffering from respiratory problems
>
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