Jon,
re:
"Be careful with modern lubricants in your transmission and O/D they seem to
have a lot of sulfides which are very bad for any yellow metals ie. brass,
bronze etc. They can cause the yellow metal to be eaten or dissolved and
can then clog the small passages in the O/D."
I don't believe you should make such a generalized statement about "modern
lubricants." I know this is true for hypoid gear oils, the sulfur coming from
the EP
(extreme pressure) addititives (you can smell the sulfur). Never used it in a
Healey
gearbox, never would. I don't believe engine oil has any sulfur-based
additives,
most use star-polymers for viscosity improvers and zinc for anti-scuffing,
added to
either synthetic or mineral base stock.
re:
"Which is why a 30W non-detergent is originally called for ..."
Called for by whom? My Bentley reprint of "The Complete Official
Austin-Healey 100-Six and 3000 1956-1968" manual calls for the same
oil to be used in the engine AND gearbox; listing several brands of 40W,
20W-40 and 20W-50 (lighter weight multi-vis for lower temperature
ranges). My Dad's BN2 manual calls for 30W non-detergent ... of course,
they didn't have (much) multi-vis in 1954. Looks to me like the Austin
engineers
learned a few things over the years.
re:
"... so small particles would settle out and not kept suspended to get in the
way."
I don't buy the "particles-settle-out-is-a-good-thing" theory. If your gearbox
is making big chunks of iron letting them settle out won't make much
difference--
you're hosed. I figure the minute particles of brass suspended in the oil won't
cause any problems, after all brass is a soft metal--effectively its own
bearing--and
soft, finely ground metals (lithium, molybdenum, etc.) are used as fillers in
the best
greases. Letting your gearbox sludge up because that's what they did in 1950
doesn't
make sense to me ... what happens when a big chunk of sludge goes on walkabout
and enters your O/D valve port? Besides, the small brass screen and the
magnetic
washers in the O/D should get any small flakes of iron or steel ... what
happens when
you've sludged-up that screen and the oil can't circulate through it to the
washers?
MT90 is a full synthetic and doesn't contain any sulfur compounds. The RedLine
people discuss their technology at length on their website. It hasn't
dissolved my
gearbox yet, but I've only had it in for 4 months and 5,000 miles ;)
As for using synthetic in the engine, the Crower comment is the first I've seen
to
indicate that syn has lower shear resistance. They are a well-known and
credible
manufacturer of cams, bearings, cranks, etc. so I figure they know something.
As often as we (should) change our engine oil synthetic doesn't seem like the
right
call in the engine.
bs
********************************************
Bob Spidell San Jose, CA bspidell@pacbell.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
********************************************
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