Good info! Just how much harsher is engagement with the larger
accumulator? As one who always tries to shift as smoothly as
possible--without slipping the clutch much, if any--is engagement so
harsh as to require a slip of the clutch which, of course, will
contribute to clutch wear? If clutch isn't used, is engagement so harsh
as to be a 'shock' to the drivetrain; i.e. U-joints, splines,
differential gears?
Bob
On 8/9/2017 5:58 AM, Ed O'Neal wrote:
>
> Mike,
>
> The original OD design used a 1 ?? 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
> ?? 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
>
>
> 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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