[Healeys] Russ Thompson

Ed O'Neal Ed at wadsworthoneal.com
Wed Aug 9 06:58:42 MDT 2017


The original OD design used a 1 ¾” accumulator piston with a concentric double spring.  This configuration was used in a lot of different vehicles including the Triumphs.  Donald Healey didn’t like how the OD engaged harshly when the clutch was not used during the shift.  He changed the design to incorporate a sleeve fitted in the 1 ¾” bore with a smaller 1 1/8” accumulator piston inside of the sleeve and a single spring.  This gave a slower engagement much like a modern automatic transmission.  However, as the OD wears the internal leakage increases and the OD will engage very slowly or not at all.  Using  the larger accumulator is a good idea (in my opinion) and will delay the point when internal leakage causes a problem.


ed at wadsworthoneal.com<mailto:ed at wadsworthoneal.com>

Edward J. O’Neal, P.E., Pte.
Wadsworth O’Neal Associates, Inc.
6418 Commerce Park Drive
Fort Myers, Florida  33966
phone:  (239) 245-8728
cell:        (239) 410-6174

From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Michael MacLean
Sent: Tuesday, August 08, 2017 8:47 PM
To: Healey List
Subject: [Healeys] Russ Thompson

     Through a reference from the list I am having Russ Thompson in Northridge, California rebuild my BN2 transmission.  It is a low mileage (10,000 mi. approx) transmission, but I wanted to be able to put it in and not have to take it back out again.  Good thing I took this precaution.  Russ found the overdrive stuck and would never have worked.  Today he showed me the accumulator piston.  The smaller center piston was scored from dirt or crap in the oil.  Russ replaced it with a one piece piston from a Triumph overdrive.  There was a huge spring below it.  Anyone heard of this?  He said engagement will be real positive now.  Even with the low mileage, the number 2 synchro was toast and will be replaced.  The other two were fine and will be re-used.  All the gears showed very little sign of wear.  The reverse gear had some surface rust on the teeth, but that can be blasted and it will be fine.  Getting closer to having the drive train is the car.
     I know I am going to start a discussion, but Russ recommends using 40wt motor oil for the transmission.  Anyone know what weight Redline MTL is?
Mike MacLean
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