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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