I put out a post about that topic near the end of last summer.
Restricting (which is what I did) or blanking the bypass, reduces the
amount of coolant that can circulate in the system without making it
through either the heater or the radiator. The bypass is there basically
to make sure the water pump can draw something even when the thermostat
and heater valves are closed; as soon as the thermostat is open or if
you have the heater on 'hot' then the bypass is redundant and in fact
reduces the cooling ability of the radiators.
Many performance-oriented engine builds block the bypass altogether; I
threaded the bypass orifice 1/8" pipe, drilled a 5/32" hole in an
Allen-head pipe plug and then inserted that into the hole. I then
drilled a couple of bypass holes into the thermostat and found that it
substantially reduced the coolant temperature.
> -----Original Message-----
> From: email@example.com
> [mailto:firstname.lastname@example.org] On Behalf Of Ron Fraser
> Sent: January 25, 2010 10:30 AM
> To: 'David and Varley Tweddle'; email@example.com
> Subject: Re: [Tigers] Thanks to all for the great ideas. Re
> my few unrelated questions email.
> I'm not sure what your trying to accomplish with
> blanking off the
> thermostat bypass. I did not see those emails. You might want to
> elaborate here and get a few more opinions.
> Ron Fraser
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