Date: Mon, 21 Jan 2002 22:27:33 -0500
Reply-To: "G. Matthew Bulley" <gmbulley@BULLEY-HEWLETT.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "G. Matthew Bulley" <gmbulley@BULLEY-HEWLETT.COM>
Organization: Bulley-Hewlett
Subject: Re: '80 Westfalia-- best way to drive over passes
In-Reply-To: <20020122002321.40862.qmail@web20010.mail.yahoo.com>
Content-Type: text/plain; charset="US-ASCII"
As a type IV veteran of 19 years, (multiple busses, 914's, and a Vanagon
Westfalia) I can tell you this is a tough motor to kill. Your concern
is warranted though; like any mechanism, even the Type IV motor can
fail.
Most T4's fail at the valve seat... I'd guess 90% drop a valve seat, or
(sometimes) burn a valve or a piston, almost all due to overheating. The
trick to keeping the head s cool is [exactly as you presume] keeping the
motor spinning over freely, and quickly so that the fan is displacing
the waste heat from the heads. Having the oil pump and oil cooler
drawing heat out of the motor helps as well, but the slower the motor is
turning over, the less efficiently these are working.
Something I read years ago (source lost to the sands of time) told me
that the T4 fan is at its most efficient at 4,200-4,800 rpm. Above and
below that you are reaching diminishing returns, either because the fan
is spinning more slowly, or because fluid dynamics at the molecular
level along the cylinder and head metal disallows any further heat
transfer, even if more air is passing by. Does that make sense? Okay...
Further, you are at the peak of both your HP and torque curves in this
range, so the motor is at its most efficient.
So if you keep you motor wound up pretty nicely on steep grades, but not
screaming, you are doing the right thing, even if you are creeping along
in 2nd at 28 mph. I've been over Wolf Creek pass a couple times, (13k)
and a number of others in WY, NM, and AZ around 11k at all temperatures,
with no problems whatsoever. Simply relax, don't "Lug" the motor, and
enjoy the trip, even if everyone is passing you.
Often times you will be passing them if it is hot enough, and they push
their beast too hard.
All of this assumes that you have all the pieces of your original
tinware in place, as well as a full and complete edge seal around the
motor, and a decent seal around the license-plate access door. If any of
this is missing, all bets are off.
From historic, walkable Mount Olive, NC,
G. Matthew Bulley
Bulley-Hewlett
Corporate Communications
Business: www.bulley-hewlett.com
Alliance: www.ntara.com
Home: www.MountOliveNC.info
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf
Of phil hans
Sent: Monday, January 21, 2002 7:23 PM
To: vanagon@GERRY.VANAGON.COM
Subject: '80 Westfalia-- best way to drive over passes
Hi everyone,
What are people's opinions of the best way to drive
over steep passes with the vanagon? What I mean is,
what is the best way to do it to bring the smallest
amount of harm to the drive train of this van? If you
are going over a steep pass in a mountain for 50
minutes, should you just go slow, like 30 mph? The
slower you go, the easier it is on the transmission
and the axles, etc. Or, is it better to go over the
pass at 80% of the speed of a particular gear, like,
either 30 mph in 2nd gear, or 48mph in 3rd gear? If
you push the vanagon, will you hurt the engine? I've
managed to go over passes alright, but I was
interested in an authoritative opinion on this
subject. Obviously, these vehicles don't have the
most powerful engines in the world, but is the tranny
and the axles stronger, or is the whole drive train
weak? Is just the engine the weak part?
The idea is not to take this vehicle over a ton of
passes, but if you can't avoid it, what's the best
approach? I have an aircooled with a rebuilt engine
with 30,000 miles on it. It is doing fine and I want
to keep it that way. Sorry for overwriting. :-)
Thanks, Phil Hanson
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