[Healeys] Engine Temperature Info ??

[Len and/or Marge Hartnett]

Steve, et al:

If one reads too many e-mails on the same subject, "facts" can get muddled. 
One says you need the thermostat to slow down the flow of coolant through 
the radiator, another says a faster flow rate increases heat transfer 
inferring that that is a proper solution to some of our heating problems.  I 
belong to the school that believes that too fast a coolant flow is NOT good.

As described to me many moons ago, the thermostat slows the flow to allow 
appropriate time for the coolant to cool.  Granted, slowing the flow will 
also allow the coolant to stay in the engine longer allowing for more heat 
to be absorbed by the coolant.  However, my understanding is that it is the 
job of the thermostat, assuming it is working properly, to attain the 
designated temperature by opening just enough to hit that happy balance 
between heating the coolant and cooling it.  Thermostats are not a totally 
open/totally closed device as some might believe from their e-mails.  They 
should open just enough to allow the appropriate coolant flow to maintain 
their designated temperature.  That should apply to the sleeved thermostats 
as well.

As to the air flow through the radiator, I can agree that the greater the 
air flow, the more heat transfer.  However, with a mechanical fan, there is 
no thermostat to control the air flow.   In that case, we upgrade our 
radiators and/or fans to boost that.

(The Other) Len
Vacaville, CA, USA
1967 AH 3000 MkIII, HBJ8L39031


----- Original Message ----- 
From: "BJ8 Healeys" <sbyers at ec.rr.com>
To: "'Healey List'" <healeys at autox.team.net>
Sent: Friday, August 03, 2012 1:23 PM
Subject: Re: [Healeys] Engine Temperature Info ??


> Al, your radiator shop may know a lot about repairing radiators, but they
> obviously don't know much about thermodynamics of heat flow.  Increasing 
> the
> coolant flow rate through the radiator will increase the heat transfer 
> rate
> between the coolant and the radiator, not reduce it.  There are other
> considerations that limit how quickly the coolant should flow through the
> radiator, but in general increased coolant flow equals increased heat
> transfer.  It's similar to the air flow rate through the radiator.  The
> faster the air flow, the more heat transfer takes place between the 
> radiator
> and air.  You get better cooling while underway than you do sitting still,
> yes?
>
>
> >
> Steve Byers
> HBJ8L/36666
> BJ8 Registry
> Havelock, NC USA
>
> -----Original Message-----
> From: healeys-bounces at autox.team.net 
> [mailto:healeys-bounces at autox.team.net]
> On Behalf Of Al Malin
> Sent: Friday, August 03, 2012 3:15 PM
> To: Healey List
> Subject: Re: [Healeys] Engine Temperature Info ??
>
> I was told by a radiator shop that a cooling system needs the restriction
> provided by an open thermostat. They say, without the restriction the flow
> though the radiator is too fast for effective heat transfer.
> _______________________________________________