[alfa] Re: alfa-digest V9 #971 - bypass restrictor installation

[AlfaNeely@xxxxxxx]

       Sounds like you got it backwards, but it is hard to tell over the 
Internet.  On the Bosch spiders, the by pass hose runs from the thermostat housing 
to the water pump.  The by pass valve fits into the upper or thermostat end, 
but that is not critical.  If the valve is in the hose and facing the correct 
direction, its placement in the hose should not matter.
       The Bosch by pass valve has a spring loaded valve.  The valve points 
toward the thermostat.  That is the part that sounds like you have backwards.  
The small end has the spring loaded end.  When the thermostat is closed, the 
water has to go somewhere.  Where it goes is it pushes the spring open and goes 
from the thermostat housing to the water pump.
       If the by pass valve you have has no spring loaded portion and if it 
is a simple restriction of the diameter, then it should not matter which end 
points where.
       I know some of the earlier Alfas had a double acting thermostat 
housing.  When the thermostat was closed, the by pass was open.  When the thermostat 
opens, the bottom closes off the by pass hose.  No restrictor would be 
required with this set up.  But I am not sure what year Alfa had what type 
thermostat.  The difference in the years gets blurred as I get older.

       By the way, I have found it easiest to just cut the by pass valve from 
the old hose.  For installation, coat the valve with anti seize to help it 
slide into place.  I also coat the ends of all radiator hoses with anti seize to 
help them come apart easier years later.

Ciao,
Russ Neely
Oklahoma City


In a message dated 11/22/2003 7:40:52 PM Central Standard Time, 
owner-alfa-digest@domain.elided writes:

> Date: Sat, 22 Nov 2003 15:11:16 -0500
> From: "Christopher Keen" <ckeen74@domain.elided>
> Subject: [alfa] bypass restrictor installation, 4C2000
> 
> Hi all,
> 
> I just installed a bypass restrictor I got from my mechanic, and wanted to 
> make sure I have it installed right. I put it in as it was installed on the 
> '78 spider parts car I got it from: on the end of the bypass hose nearest 
> the water pump, and with the small opening facing the water pump. Can 
> someone confirm that this is correct?
> 
> Thanks
> Chris Keen
> '77 spider
> Los Altos, CA
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