[Healeys] OD Longevity

[Jean Caron]

Bob,
I am sure you will get some good answers from people that have them rebuilt but I can tell you that mine in my BN6 was rebuilt at 67,000 miles. Having said that, my car is parked about 5 months of the year for winter and when I purchased it it had sat for 11 years before that. When I first put it on the road I changed the oil and that was it, drove it about 6 more years and it gave me some trouble on a trip to Georgia, got the oil changed in it near Chicago, continued on my trip down and then back home and rebuilt it that winter. All was well except it was pretty full of sludge and stuff in the side overdrive piston area. I replaced the bronze thrust washers and have run about 30,000 miles since without issues.

Jean
________________________________________
From: Healeys <healeys-bounces at autox.team.net> on behalf of Bob Spidell <bspidell at comcast.net>
Sent: May 15, 2016 5:04 PM
To: Healeys
Subject: [Healeys] OD Longevity

Listers,

I've always been a bit in awe of the Laycock De Normanville overdrive
units as fitted to our Austin-Healeys.   To me, it's a wonder of
engineering elegance and simplicity--well, except for the electricals,
maybe--and as it's an 'axial' design there are no significant side loads
to wear out layshafts/gears and bearings. However, all things have a
life span and I'm wondering what is the typical life for the A-Series--I
believe that's what's in my BN2 and BJ8--OD units under 'normal'
(non-racing) usage?  The unit in my BJ8 has over 190K miles on it and
AFAIK it has never been overhauled, and I'd hate for it to die on one of
my long road trips as we inevitably spend hours on straight stretches of
interstate highways (I do have a 3.54 rearend, which would make things a
bit more tolerable, but the 22% reduction in RPMs is hard to beat;
except maybe with 28%).  I've used Redline MT-90 in the gearbox/OD for
the last 40-50K miles or so and--some will think this is blasphemy--I
only change it out every 20-30K miles (I don't buy into the 'use
non-detergent oil so the all the sludge will drop to the bottom' theory,
when I change out the syn oil I note the oil is clean and light-colored,
and that there is finely-ground brass shake suspended in the oil but it
is so fine you can't feel any grittiness at all if you rub it between
your fingers; and note that some of the best greases--lithium,
molybdenum, etc.--are finely ground soft metals suspended in oil).

Anyway, what's the collective wisdom on this: run 'em until they quit,
or rebuild them at 100/200/300/?K miles as a precaution?

As usual, TIA.

Bob

ps.  I'll keep using 74W-90 in the diff as recommended by y'all.
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