Date: Sat, 6 Jan 2001 14:30:33 -0800
Reply-To: Daniel Schmitz <djs@GENE.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Daniel Schmitz <djs@GENE.COM>
Organization: Genentech, Inc.
Subject: Re: Air-cooled Vanagon history
Content-Type: text/plain; charset=us-ascii
As to why Volkswagen switched to a water-cooled design for the Vanagon
in 1983.5, the air-cooled "Type 4" VW engine that powered the early
Vanagons was a hold-over from the earlier, lighter bus. As such, it was
ill-suited to powering the Vanagon for the following reasons (among
others):
1) It made only 67hp, barely enough to move a 3500lb+ vehicle with lousy
aerodynamics at reasonable highway speeds without overly stressing the
motor.
2) The engine provided only marginal cabin heat; many vans in colder
climates needed an auxiliary gas heater to be comfortable. A
water-cooled engine includes a relatively efficient means of heating the
cabin.
3) This engine, because of it's application, was subject to mechanical
failures such as burned pistons and dropped valve seats. It tended to
run overly hot due to the load imposed on it. It tended to have a short
service life.
4) This engine was not going to be able to meet ever tightening smog
regulations without further strangling it's already anemic performance.
5) As a general statement, and all things being equal, air-cooled
engines of a given capacity are necessarily less efficient than
water-cooled engines of the same capacity due to a higher percentage of
combustion energy being lost to heat rather than translated into
horsepower. Or, stated another way, a water-cooled engine turns more of
it's combustion energy into horsepower and gives up less of it as heat,
thus making it more efficient.
6) This engine was at the end of it's useful development cycle,
especially in light of a changing world that was moving toward more
efficient and less polluting powerplants.
As an aside, the Type 4 is not necessarily cheaper to maintain and fix
than the water-cooled four. It's parts prices can in some cases be more
expensive than the wbx. And it is arguably more difficult to work on due
to the cooling system sheet metal that covers the engine. I have owned
Vanagon powered by both engines.
All this having been said, Type 4 air-cooled is a great engine for
powering Porsche 914s, which weigh only 2000 lbs, are very aerodynamic,
and take advantage of the Type 4's tractor-like low-end torque rather
than high-rpm power.
All of the above is probably more than you wanted to know. Apologies if
so.
Dan
1987 Westfalia
1982 Adventurewagen (that is, until I donated it to charity)
1975 Porsche 914
phil stanhope wrote:
>
> If VW made air cooled vans for MANY decades, then why then was there a
> problem with the vanagon air-cooled. I figure by 1980, they had worked out
> alot of overheating/ ventilation problems. Air cooled engines are cheap,
> easy to work on, and have relativly good power (with some mods.)
>
> So why did they go to the wasser-leaker?
>
> Phil
> 84' all white westy:"The millenium Falcon"
>
> _________________________________________________________________
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