I helped start this and at the risk of adding gas to the dying embers, I
must add a few things, perhaps to be viewed as parting thoughts thrown
together this morning as my caffeinated beverage takes hold.
I'm old enough to have served with the M-715 in the U.S. Army during the
early '70s. My unit, the 558th Transportation Company, had a passle of '715s
and '729s, as well as a few M-37s. I heard a few complaints about them at
the time, along with some about M-151s and some on a version of the 5-ton
(the details of which I do not recall), but the Kaisers didn't seem to have
any more downtime than anything else in the motorpool. I was assigned one
for about 4-months for a TDY job and we beat the fecal matter out of it on
some "unofficial" four-wheeling jaunts. It did not give us a single problem.
So much for my own anecdotal recollections, which are really of as little
value as some of the others we've heard. Incidentally, I've owned an M-37,
and performance-wise, I don't see a great deal of difference between it and
the '715, though I'd have to say I like the M-37 better.
Getting to facts, the OHC 230 was based on the Kaiser L-head 226ci, an
engine with a good reputation over many years. When A.C. Sampietro designed
the 230, it was intended to outpower the competition... and it did! While
rated at 140hp (in civilian 2-bbl form), period dyno tests actually show it
at 155hp. In the lightweight Utility Pickups and Wagons, in which it debuted
in '62, and later in the Wagoneers and civvy Gladiator trucks, it resulted
in a fairly sprightly 6-cylinder machine. It did suffer from oil leaks and
oil consumption problems. The oil leaks were concentrated around the motor
mount plate sandwiched between the block and the front cover, a feature
eliminated on the '715, which had block mounted engine mount brackets. The
leaks were reduced by self-sealing nuts and Permatex. Oil consumption was
due to non-seating chrome rings, poor drainback from the head and poor valve
stem seals, all of which were updated in engines built after early '63. The
mechanical problems commonly mentioned (cams, rod bearings, etc.) were
almost always the result of low oil levels from the leaks and the oil
burning.
After updates, the civvy 230 was reasonably reliable, but still
tarnished by the earlier troubles. It was replaced partway into'65 with the
AMC 232 and an optional AMC V8. It isn't clear exactly how the major
redesign occurred for the engine's intro into the military rigs for the
prototypes built in '66, but all the test info I have says they performed
very well in tests. In fact, the tests show no engine problems of any kind.
As with all military testing, the goal was to determine if the vehicle met
the requirements for military service. The M-715 did, and then it came down
to bids. Kaiser was the low bidder.
The military OHC230 engine is very much different than the civvy
version. The parts interchange is about 50% and many civvy OHC owners have
been disappointed because they cannot substitute the more common GI parts
for the dwindling supply of civvy parts.
As to the Army dropping the '715, it had less to do with the vehicle
than it did with budget cuts and changes in thinking about what a tactical
vehicle should do. The Kaiser was not completely replaced in tactical jobs
until the Humvees debuted and the CUCVs replaced them, or augmented them, in
non-tactical roles starting in the 1970s as the last of the old M-37s were
retired. There weren't enough M-715s built (only about 30,000) to replace
all the M-37s in service and so with the post Vietnam budget cuts and force
reductions, the CUCV plan filled the gap. During this time, the testing and
conceptual thinking that led to the Humvee was going strong (the 1971-77
XM-311 project for example).
The M-715 was the last gasp in the WWII line of thinking on tactical
vehicles, which used a single vehicle for a single task. The Humvee concept
replaced several vehicles with a single, basic platform that was adaptable
to many tasks. Even the Humvee has not been without problems, and you can
find ex-GIs telling negative stories about them that are similar in tone to
the M-715 stories.
The OHC engine was produced for many years (into the late '70s at
least) in Brazil after the M-715 production stopped in Brazil, in both cars
and trucks, and even had a fairly successful career as a racing engine in
South America, capable of turning 7,000rpms. Some were installed into race
car chassis and raced here, an example of which is currently being restored
in Ohio.
Overall, the OHC 230 suffered from being ahead of it's time and perhaps
introduced a bit too early. The civilian problems are well documented in the
reams of service bulletins from '62 and early '63. By late '63, they drop
significantly as bugs were worked out. The military version was reputedly a
big improvement of the civvy version, and as to it being grossly unreliable
in military service all I've ever heard are "war stories." I'd welcome any
documentation. My anecdotal experiences were completely different than some
I've heard here. I'm willing to be convinced, but I have an idea on how the
OHC's reputation came about.
Many years as a mechanic and then as an automotive journalist have led
me to believe in the "extension of a narrow range of experience" theory. One
tech, or a few techs, at one shop have problems with a particular vehicle.
By extension, every other vehicle everywhere is thrown into the same boat.
When I went from being a tech on a particular brand with a "reputation," to
a much broader viewpoint, I learned that, statistically, the problems were a
lot less common than I had originally believed. There are many factors that
can contribute to a particular shop having more problems than others,
including environmental conditions, the competence (or lack thereof) of the
techs and sheer chance. For every shop you find badmouthing a particular car
(or engine), you find two others going broke for lack of work.
Jim Allen
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