*This message was transferred with a trial version of CommuniGate(tm) Pro*
-----Original Message-----
From: mblair1@home.net <mblair1@home.net>
To: Military Vehicles List <mil-veh@uller.skylee.com>
Date: 15 April 2000 04:08
Subject: Re: [MV] Oil changes
I have to agree with Mark, now this may run on a bit so all you people
disinterested in lube oil should hit delete here.
>
>"Sean Bathrick" <Bathrick@imcchemicals.com> wrote:
>> Kind of along the same topic. I did an oil change in my M38A1 last
>> year and decided to use 5W-50 oil instead of the NAPA 30
>> non-detergent.
>[...]
>> Never will I run multi-viscosity oil in my jeep or truck again. Just
>> my 2 cents.
>
I think Sean said he had non-detergent SAE30 in the engine previously and here's
a potential problem.
The Allied armies changed to detergent oils in 1942, it is well recorded in the
Ford CMP manuals and shows it was called then H.D.30. The feature of
non-detergent oils is the deposition of heavy sludge around the quieter corners
of the engine and it is recognised that simply changing to detergent oil on a
well used and sludged engine would be problematical.
The detergent oil will shift all the accumulated deposits and carry it off round
the system likely choking the filter and fine oil drillings in short order. The
example of the Ford CMP manual recognises this and defines a flushing procedure
followed by several very low mileage oil changes, in clean new engines or
re-builds this is not a problem at all, Ford actually state the chassis and
engine number at which H.D.30 was used in manufacture.
So we can put a stake in the ground for the introduction and retrospective use
in Allied MV's at 1942, H.D.30 later becomes SAE 30 to MIL-O-2104B (C and D now)
and the UK OMD 110.
>I don't understand why folks run anything other than what the
>manufacturer and/or lube order recommends.
>
I agree with Mark, there may very well be some motors that will accept or
benefit from the use of a multi-grade but without the resources of the
manufacturer who can tell, certainly the multigrades didn't appear until around
the 70's so we can only surmise when engine designers used these properties in
new designs.
Multi-grade seems to be aimed more at the domestic market to alleviate potential
domestic car hassles and is in any case only a straight oil with much added
chemical wizardry, largely long-chain polymers, to counteract thinning with
temperature, difficult cold starts and excessive cold oil pressures, cynically
you could consider multi-grade lube to be a production easement for all these to
allow cheap manufacturer design where they are forced into high efficiency, lean
burning hot engines with just adequate batteries and starters, apart from
liaison duty OD sprayed domestic types the mil likely has no time for this in
actual mil specific fighting vehicles.
The current multigrades we use domestically are typically running as a hot SAE
30 anyway and I really wonder if the "magical" 5W-40 brown glug we tip in our
cars is still actually 5W-40 after the first 1000 miles. . . . . . . . . . . .
>If the LO calls for a single-grade oil, it doesn't seem to me to be a
>good idea to substitute a multi-grade oil. I realize that it can be a
>pain to change oil seasonally in areas with wide temperature swings,
>but in areas where it's not necessary (like where I live),
>
The typical specified ambient operating range of SAE 30 isn't really that bad,
23ºF to 89ºF is specified by RR for the B Range mil engine and that covers most
of the world, surprisingly many big diesels and other continuously thrashed
engines like those found in contractors small plant (Honda, Briggs & Stratton)
specify SAE 30 only.
There is a worrying feature of multigrades that has a direct bearing on heavily
worked engines where these are specifically designed to be heavy consumers of
oil to achieve continuous operation in that multigrades will leave a metallic
ash when burnt which is aggressively destructive to piston rings, not a problem
in the virtually zero oil consumption car engine but of concern in designs
intended to use oil heavily.
Consulting with both RR specialist engine division here and the tech departments
of several multi-national oil companies, they all agreed without prompting that
multigrades were potentially unsuitable in designed high consumption engines and
further that the straight 30 is mechanically stronger, as most 50s - 70s UK MVs
specify OMD 110 (SAE 30) for gearbox (not transfer note) use also they strongly
advised against a multigrade here.
The B81 in the FV623 has "2 galls" stamped in the dipstick between "Max" and
"Min" so you tend to get blasé about 1/2 gallon top-ups. . . . . . . . !!
I would be wary of putting too much store by what the oil pressure gauge says,
if its in the makers stated range with the specified oil all's well, however,
using thicker stuff by way of a multigrade or whatever to get a satisfyingly
high reading is just covering things up.
We need to be aware that the gauge, if its not lying that is, simply tells you
the pressure at the tapping point which may or may not have anything to do with
a sufficiency of lube reaching the critical far corners of the engine, high
readings could actually be indicative that the far end main and big-end bearings
are being starved.
>I see *no*
>reason to use anything other than the recommended oil. The recommended
>oil for both my deuce and my HMMWV at the temperatures they encounter
>is plain ol' SAE 30, year-round, period.
>
Quite so.
The HMMWV engine is hardly an old W.W.II design either.
>My trucks get Rotella SAE 30 all year round, and in the unlikely event
>that I move somewhere that gets under 15 degrees F in the winter, I'll
>use the oil(s) recommended by my LOs. I don't design engines for a
>living, so I know better than to second-guess the engine manufacturer.
>
Rotella 30 is a good, high detergent SAE 30 and likely MIL-O-2104D qualified.
I don't design engines either which is why I consulted with those who do.
>Just my two cents worth. Use whatever oil you want... but don't sell
>me your old truck if you don't follow the LO.
>
Perhaps we should bear in mind that the excellent attributes of un-glamorous SAE
30 are not screamed from every bill-hoarding, race car and the TV. . . . . . . .
. . .
The last quote from the divisional manager of RR Specialist Engines to me was:
"We designed, tested and qualified the engine range with SAE 30/OMD 110, but its
your engine now so you can put in it what you like."
I like detergent SAE 30 to MIL-0-2104D, efficient and cheap without a
multi-million ad campaign to support.
Richard
(Southampton - England)
This archive was generated by hypermail 2b29 : Mon May 01 2000 - 05:30:05 PDT