Guys, guys, guys. Not the thermo thread again.
Someone grab a head off the shelf. Look in the thermostat location.
Note the port that leads from the left hand side of the thermostat cavity.
This is a return port that bypasses the thermostat. When the thermostat is
completely closed water flows through this port and continues to circulate.
The engine was originally designed to accept a blanking thermostat that when
open would cover this port. In the 60s the blanking thermostat was
discontinued, I have read due to reliability problems. When a standard
thermostat is open, some coolant will continue to flow through this bypass
port without being cooled.
The blanking sleeve effectively closes off this bypass port ensuring
that all coolant flow is through the radiator. It should be good for a
couple of degrees of extra cooling IF the regular thermostat is not used.
This design is used on Jaguar, Triumph and MG. The Triumph and MG
both have pretty small bypass ports, so do not have any problems running
with a standard thermostat. The early Jags however have big bypass ports
that reduce cooling substantially. Jaguar specialists do carry a modern
version of this blanking thermostat for these applications but it is very
expensive. I have the feeling that a blanking thermostat would be helpful
on a car with marginal cooling such as an MGA. The part is available from
your choice of vendor under #434-155. Keep in mind that the operating area
of the sleeve must be clear of rust and other subteranean growths.
Kelvin.
> -----Original Message-----
> From: paul.hunt1@virgin.net [mailto:paul.hunt1@virgin.net]
> Sent: Wednesday, August 16, 2000 10:55 AM
> To: Christopher W. Reichle; Max Heim; Larry Colen
> Cc: MG List
> Subject: Re: Almost enough cooling
>
>
> The reason for fitting a blanking sleeve in place of a
> thermostat is to keep
> the water flowing through the engine at the designed speed.
> If it flows
> through too fast you get localised turbulence and eddies in
> the block and
> consequently hot-spots.
>
> PaulH.
>
> ----- Original Message -----
> From: Christopher W. Reichle <creichle@yahoo.com>
> To: Max Heim <mvheim@studiolimage.com>; Larry Colen
> <lrcar@red4est.com>
> Cc: MG List <mgs@autox.team.net>
> Sent: Wednesday, August 16, 2000 5:13 AM
> Subject: Re: Almost enough cooling
>
>
> > Um, I don't think that statement makes much sense. No flame
> intended but,
> > think about this logically... The radiator gives off a
> certain amount of
> > heat, transfered from the water to the metal of the
> radiator and to the
> air
> > passing over the radiator. I think the part of the equation
> that you are
> > leaving off is that when water flows faster through the
> radiator the water
> > exiting may be hotter but there but more water is cooled
> (more heat is
> > extracted from the system).
>
> etc.
>
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