Date: Sun, 28 Oct 2001 16:08:20 -0500
Reply-To: Dennis Haynes <dhaynes@OPTONLINE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject: Re: 30mm vs. 40mm Hub on Diesel Water Pump
In-Reply-To: <01C15FB3.7C60FC00.echomhs@gis.net>
Content-type: text/plain; charset=us-ascii
The difference is the pulley mounting. Nothing to do with the vanes.
That pump you have the stamped steel impeller is probably a GMP brand
pump. These are usually made in Japan. They made many pumps for many
vehicles with the idea of being a low cost replacement eliminating the
need for rebuilt pumps which are used for many American replacements.
They claimed the steel impeller pumped more water, (it did not) and they
offered a "lifetime" warranty, (go collect).
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Maynard Southard
Sent: Sunday, October 28, 2001 1:21 PM
To: vanagon@GERRY.VANAGON.COM
Subject: 30mm vs. 40mm Hub on Diesel Water Pump
Brace yourself for a dumb question ... Can anyone tell me what the
difference
is between the 30mm and 40mm hub on the water pump for the 1.6L NA
diesel?
(Please don't say 10mm!)
The Vanagon diesel requires a 40mm hub on the water pump. I've always
thought
the dimension referred to the diameter of the surface that the pulley
attaches
to (the "hub", right?), but I have 3 water pumps on my work bench, one
from my
'82 Westy diesel (and I know it is not original), one from my '82
Passenger
diesel (and I know the whole engine is not original) and one from an '84
Jetta
Diesel with no A/C (which supposedly also takes the 40mm hub, but I know
it is
not original also.) The "hubs" are all the same diameter, but the vanes
are
different. One has formed steel vanes (kind of like bent fork tines)
and the
other two have a cast vanes (and they are not identical). Am I just
looking at
different manufacturing approaches to the tines, or have I misunderstood
which
hub the measure refers to?
And finally, why does VW use two different hub sizes? I think it has
something
to do with the pulley drive system - as the Vanagon application uses one
belt
to drive the water pump from the crankshaft pulley and a second belt to
drive
the alternator from the water pump pulley. On late 70's and early 80's
diesels
with A/C, there is a single belt that drives the water pump and A/C
compressor
from the crankshaft pulley and another belt that drives the alternator
off of
the A/C pulley. These all seem to spec the 30mm hub. Is the difference
because of the way the pulley is attached?
Thanks for any insight.
Maynard Southard (OvO) '79
'82 Westy Diesel "Reinhardt"
'82 Vanagon GL Diesel "Sluggo"
'93 EV GL "Klinger"
'00 Golf GLS TDI "WooHoo"
'84 Jetta GL TD "Donor"