In a J type the pressure was related to the power of the engine, 460 PSI is
probably OK for a Sprint although I don't have the book that lists the
pressures anymore. The lowest pressure was for a Spitfire at about 350,
2000s had around 400 so 460 is OK for a Sprint in normal use. In any case
high oil pressure tends to make the overdrive action a bit violent. If you
want to raise the pressure it depends what type of relief valve is fitted,
the early ones (which you probably have) have to have extra washers fitted
after taking the inner bit apart, later ones can have shims fitted to raise
the pressure much more easily. Later relief valve assemblies can be retro
fitted to early J types.
John Kipping
----- Original Message -----
From: "Geoffrey Byrne" <gkbyrne@optushome.com.au>
To: "Friends of Triumph" <fot@autox.team.net>
Sent: Tuesday, April 26, 2005 12:42 AM
Subject: Overdrive Oil Pressure
> Dear FOT advice please
> Have just rebulit J type OD from Dolimite Sprint replaced all o rings ,
new
> oil pump both piston and barrell. on my test bench at 40mph in top gear I
can
> only get 460 psi oil pressure . should be 500 to 550
> oil pump relief valve has .065 inch spacer and transfer passage restrictor
> bored to .070. Accumulator piston is O ring type
> Oil is Castrol 70/90 . filters are spoptless. Have stripped and rebuilt
twice
> and found no problem
> I have rebuilt dozens of ODs and can always determine why oil pressure is
low
> but this one is a real mystery.
> Any ideal guys
> Geoff Byrne
>
>
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