Date: Tue, 30 Mar 1999 10:08:29 -0700
Reply-To: "Jon B. Kanas" <kanas@QUALITY.QADAS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Jon B. Kanas" <kanas@QUALITY.QADAS.COM>
Subject: Re: Ladies Crossing the US
In-Reply-To: <a646e07.3700ed8b@aol.com>
Content-Type: TEXT/PLAIN; charset=US-ASCII
Jeff,
In the past 25 years I have owned both aircooled and watercooled VW
busses, as well as being the proprietor of a VW service shop for a number
of years in the 70's.
The early (pre-72) busses were significantly underpowered for their
weight, resulting in premature (60K to 70Kmi) main bearing
loosening, which causes low oil pressure, overheating and engine failure.
Unlike the later aircooled engines, the type I engine in a bus was much
more likely to suffer rod failure than valve problems.
The type4 aircooled engines are a better match for the vehicle weight, and
are significantly less failure prone due to excessive stress. The life
expetancy of these engines in the much lighter 914 is only slightly longer
than the expected life in a bus. The life expectancy is in the vicinity
of 100k to 110k miles if properly maintained. Due to the extreme
temperatures these engines see, failures of various sealing surfaces are
common, especially the push rod and oil cooler seals. While not
catastrophic in nature, these leaks are irritating to the average driver
and rather expensive to repair. The predominant mode of failure is
exhaust valve stem fracture, resulting in a catastrophic failure when the
piston strikes the valve head which is now inside the cylinder. When
disassembling a typeIV engine, it becomes apparent that the heads are not
adequately cooled, particularly when the displacement of the engine
reaches 2 litres. Lubricating properties of motor oils begin to degrade
at temperatures beyond 240F, and the typeIV engine in a bus frequently
reaches these temperatures during extended summer use.
The Wasserboxer engine is a much more complex engine, partially do to the
manner in which the watercooling for the heads is implemented. The engine
durability is much better because the operating temperature is maintained
around 200F maximum, so the engine does not reach temperatures where the
oil begins to degrade. Lubrication is maintained, wear is reduced, and
the engine lasts longer. Seals and gaskets are not subjected to the
temperature extremes which exist in the aircooled engine, and last much
longer... particularly push rod tube seals. They are, in fact, less
likely to leak. In my experience, life expectancy of the
wasserboxer is around 150K miles. At that point the common problem is
valve guide wear, with excessive oil consumption as the primary
symptom. In these cases, we recommended a complete rebuild due to the
duplication of labor costs if a valve job alone was to be performed.
In many cases, we also found excessive camshaft wear when the case was
apart. I suspect that the material from which the camshaft is
machined was not hard enough, since there was no evidence of
lubrication problems on the cam journals, only wear on the lobes.
Yes, the wasserboxer is a more complex engine, and there are more parts
which can fail. It also has an additional 10 years of mechanical design
experience and advances in materials which did not exist when the
aircooled engines were built. Overall, I believe that it is a better
overall engine than the typeIV engine for use in a Vanagon.
My 1983 vanagon reached 134K miles before I sold it, and was showing
little mechanical wear. I have seen others approaching 200K miles which
are tired, but still satisfactory. On a long summer trip, the temperature
issues are the paramount concern, and the watercooled configuration
addresses these problems much more successfully than the aircooled
configuration.
We should keep in mind we're discussing vehicles whose overall life
expectancy exceeds the industry average by three-fold. For the trip
we're been discussin on the list, either engine should perform well if
starting out with 60K miles on it. If the engine has 100K miles on it,
I would be more comfortable with the watercooled unit, all other things
being equal
If you're driving an aircooled bus, it is at least 15 years old. How many
other vehicle owners would even consider taking a vehicle this old
cross-country?
Regards,
Jon
On Tue, 30 Mar 1999 Fonman4277@aol.com wrote:
> In a message dated 99-03-30 10:21:18 EST, you write:
>
> << The water cooled ones (yours) are much
> more reliable than the air cooled ones on long trips because the engine
> temperature is more accurately controlled. My 1987 is my third bus, an >>
> Wait a minute, you leak water, we leak oil. At least you water-cooled folks
> have heat in the winter! How can you really say one is more reliable than the
> other? Jeff
>
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