[Healeys] Overdrive pressures

[Bob Spidell]

On a side note: Someone commented that the higher pressures reported may 
have been caused by the owner using the O-ring style accumulator pistons 
as opposed to the 'traditional' metal rings style. Though I think the 
O-rings are a good idea--I would have used them if I'd known/thought 
about them--I don't think that alone would necessarily account for 
higher pressures. Accumulator pressure is limited by relief holes in the 
bore; when the piston is pushed far enough back, the holes are exposed 
and allow fluid to flow out of the accumulator (the piston both builds 
pressure and regulates it). The metal ring type pistons--they look like 
small engine pistons--should develop the spec'd pressure; but the 
O-rings would be less likely to score the bore and cause pressure loss 
over time. Or, are the metal ring type that leaky? Two things could 
cause higher-than-spec pressure: 1) much stronger accumulator spring(s) 
or 2) an inaccurate gauge. The oil pressure gauge on my BJ8 registered 
zero PSI for many years--obviously, it had SOME pressure--but my car 
miraculously gained 20PSI at idle when I had the gauge rebuilt and 
adjusted to a standard (i.e. 'calibrated').

On another note; just caught an episode of Wheeler Dealers where Elvis 
fixed an inop O/D on a Triumph Dolomite Sprint (I had never heard of the 
car before but, of course, 'Dolomite' has Healey history). The O/D 
appeared to be a Laycock, but the offending part--the solenoid, 
natch--was a more robust-appearing unit mounted horizontally on the 
bottom of the O/D. Anyone know anything about what, presumably, is a 
later Laycock unit?


On 8/9/2023 11:39 AM, warthodson--- via Healeys wrote:
> Dave, I found this in my Spam file. Surely someone has an opinion 
> concerning the 500-550 psi!
> Gary Hodson
>
> On Wednesday, August 9, 2023 at 03:05:56 AM CDT, John and Kerry Rowe 
> <jtkarowe at gmail.com> wrote:
>
>
> I would be very happy with those pressures. I wish!
>
> On Tue, Aug 8, 2023 at 1:39 PM David Wirken via Healeys 
> <healeys at autox.team.net> wrote:
>
>     Recently overhauled OD when testing the pressure, it measured 500
>     to 550 psi on the gauge.The book says it should be 470 to 490 PSI
>     and drops about 80 PSI when engaged or disengaged and jumps back
>     up to 470 PSI very quickly.
>     Question is " should I be concerned about the high numbers I am
>     experiencing ?
>
>     THANKS for your input
>
>     Dave
>
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