Subject: Re: [Fot] A type O.D.

From: "Steve Yott" <[email-masked]>
Date: Sun, 28 Jul 2013 14:33:44 -0500

The A-Type non return valve operates as a check valve for the oil pump.  If
the valve is leaking or not closing etc. you will not be able to develop
full operating pressure which should be in 450 to 550 lbs. area.  It really
would not provide any advantage to make the spring stiffer as it only holds
the ball valve in position as the pump pressure pushes it open.  If you are
looking for an increase in operating pressure the only means is to use
stiffer accumulator springs or shim the current spring.  Be very careful
with the second option as I have seen many broken overdrives created by
someone thinking that more spacer means more pressure and that is good!!!
Wrong, it can be very bad if there is too much spacer installed and the
accumulator springs goes into coil bind during operation without exposing
the relief ports.  This can create extreme pressures to the point where
parts break!

Steve Yott

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of [email-masked]
Sent: Sunday, July 28, 2013 11:30 AM
To: team, FOT
Subject: [Fot] A type O.D.

Hello can anyone tell me the function of the non return valve on the A type
And if the strength of the spring is changed what would be the resultB B
thanksB  rob _______________________________________________
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From: Larry Young <[email-masked]>
Date: Sun, 28 Jul 2013 16:31:09 -0500

Actually, the spec pressure is 350 for a large accumulator type (pre 
TR4A) and 450 for the later ones with a small accumulator.  Racers 
prefer the large accumulator and often go to higher pressure for a 
quicker and more positive shift.  Anyone that works on these should have 
a pressure gauge.  Our article in the maintenance section at vtr.org 
gives guidelines for the effect of shim thickness on pressure and 
information on where to buy a pressure gauge.
Larry Young

On 7/28/2013 2:33 PM, Steve Yott wrote:
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