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Re: Overdrive help

To: jantoms@vbe.com, fot@Autox.Team.Net
Subject: Re: Overdrive help
From: WEmery7451@aol.com
Date: Wed, 3 May 2000 09:26:16 EDT
Tom,

I just released how huge this file is, and it probably wont reach you.  I 
will try to copy and paste a shorter version:

Subj:    Racing with overdrives
Date:   1/24/00 3:23:41 PM Pacific Standard Time
From:   Gt6steve@aol.com
Sender: owner-fot@autox.team.net
Reply-to:   Gt6steve@aol.com
To: FOT@autox.team.net
CC: Vintage-race@autox.team.net

Does anyone know and care to share experience on what to do to the D or J 
type laycock overdrives to beef them for racing.  I'm sure higher hydraulic 
pressures are in order but I don't know much beyond that.  Any help would be 
appreciated.
Thanx, Steve

Subj:    Re: Racing with overdrives
Date:   1/25/00 10:31:38 AM Pacific Standard Time
From:   WEmery7451@aol.com
Sender: owner-fot@autox.team.net
Reply-to:   WEmery7451@aol.com
To: Gt6steve@aol.com, fot@autox.team.net

Steve,

I have been using the overdrive units fitted to the TR-3/4 gear boxes for 
about 3 1/2 decades.  I am not sure if this information applies to GT-6 
overdrives.  Someone from British Leyland (Michael Barrette?) connected with 
Group 44 at the time gave me the following instructions back in the 70's:

1) Remove four of the eight springs (the inner ones).

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.

3) Drill out the operating valve hole from 0.042" to 1/16" (0.0625").

He also encouraged me to forget about the OD unit and use a 4:11 rear end 
ratio with a straight 4-speed gear box.  They didn't tell me at the time 
about the close ratio gear boxes that they were using.

Periodically, my OD unit would quit working.  I would take it apart and find 
nothing wrong, reassemble it, and it would start working again.  Since I 
started using Ams Oil 80W-90 gear lube, I have had no trouble.  I am sure 
that better synthetic oils are now on the market.

Good luck,
Bill Emery 

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