Had a talk with our diesel rebuilder when I picked up one of the company
HUMV's, and asked what he thought about the 6.2 vs. the 6.5's. The gist
of our conversation was that the later 6.2's seem to exhibit less of the
head and web cracks than either the early 6.2's, OR the early 6.5's which
superseded them.
I asked him what he felt was causing the 6.2's to crack in what I consider
numbers approaching the Black Plague, and suggested that
continuous ether starts or lugging might well be causing the web cracks,
and that the head cracks seemed to be the result of poor heat dissipation.
The rebuilder agreed on the head comment, but said:
"We get old guys in here with babied trucks that you know damn well
have never seen a rough day in their lives, or a can of ether for that
matter, and it doesn't seem to make any difference whatsoever."
Paul, the rebuilder, also kept track of the various conditions the 6.2's were
used under as part of his customer record-keeping. He said that whether
the units were in pickups, or heavy-duty machines, with automatic
transmissions or manual transmissions, or used in one-ton, half-ton or
three-quarter ton applications didn't seem to matter one whit
statistically, to
the point that "nine out of ten that I have come in for various problems
all have web cracks."
I wonder if the Army or GSA have done any homework as respects the failure
of these engines. A great many of the early DRMO CUCV-family trucks had their
powerplants yanked at the Can. point before sale (but with
transmission/transfer
assy's left in place), supposedly as part of some program to eventually
re-emerge rebuilt and refurbished as replacement HUMV engines. Perhaps
the catastrophic failure rate of HUMV engines outstripped the system's
capacity to
replace them??
Off-topic a bit, but we also talked glow plugs. I'm sure a few of us are sick
of trying to extract failed and swelled glow plugs from CUCV and HUMV
vehicles, and on the 12V civvy-side, AC/Delco has come up with a new
plug, the 60G, that will apparently take nominal voltage all day long without
swelling, melting, failing or losing its tip in the combustion chamber. I've
a candidate for a 60G installation in the form of a problem-child M1010 that's
had a number of independent and unrelated glow-plug system failures, and
once the HUMV ones in my personal 1009 chuck their cookies, I expect
to replace them with the 60G's as well. A bit of rewiring will be
necessary, but it sounds like a fair trade-off in the CUCV's. Can't think
of a way
to adapt them to the HUMV without placing a hefty starting-load on one battery
only - unless they'll run happily on 24V, or a 24V equivalent is offered by
AC Delco.
Andy Hill
MVPA #9211
(who found out the hard way what happens when your HUMV PCB
grounds aren't what they could be as respects glow plug operation!)
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