[Healeys] Thermostats

Sun Sep 16 11:52:51 MDT 2018

I tried to help myself but I have once again been drawn into a discussion
about engine thermostats. As I read the posts the underlying questions are
what is the best thermostat and do I have the right one? I will correct one
Poster who suggested the role of the thermostat was to control pressure in
the cooling system. While thermostats may have an effect on pressure in the
cooling system that is the job of the radiator cap. 

I suggest the best thermostat has these features: fails in the open position
i.e. coolant circulates through the radiator. You can get home with a cool
engine but not a hot one. Blocks circulation of coolant between the engine
and radiator until the engine has reached its predetermined temperature.
i.e. The thermostat fits the housing and seals when closed. The thermostat
fully opens about 15-20 degrees above its rated temperature. The thermostat
should have a "jiggle pin" or "check valve" that allows trapped air in the
cooling system to pass through the thermostat and be released from the
system.

Do I have the right one? Based on old manuals I have seen there were two
temperature ratings for 3000 Healeys, Summer 70 Deg C/160 Deg F and Winter
86 Deg C/185 Deg F. I believe the thinking behind the two thermostat
approach was to reduce boiling the radiator in summer and to make the heater
work better in the winter. Depending on where you live and and the driving
conditions may influence which end of the range you want to be at. If you
live in Florida and/or drive in slow moving traffic I would suggest the 160
degree. Your cooling system will have more reserve when traffic slows. If
you live in Ottawa 185 is likely better as it is winter all the time.
However, the most important factor is not opening temperature but does the
thermostat properly control the coolant temperature. If you have a 160
degree thermostat and the coolant temperature fluctuates between 160-180
then it is the right one. Likewise the 185 should stay between 185-205. It
is most important for the cooling system to stay between the lower and upper
temperatures. If the temperature is not between these two points then the
cooling system is "not in control".

Bottom line is if the cooling system is "in control" and you are happy with
the way the car warms up you have the right thermostat.

Harold

  _____  

From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Linwood
Rose
Sent: Sunday, September 16, 2018 7:19 AM
To: Rossm
Cc: Forum Healeys
Subject: Re: [Healeys] Thermostats

I would like to go back to Steve Byers' comment. I am not so much concerned
about my car overheating. When the engine was rebuilt it was thoroughly
cleaned to get rid of all sludge. I run an aluminum radiator, have built and
installed air ducting for improved flow. I do not have an electric fan.  

My problem was that my engine ran cool and would take quite a while to "warm
up." I think I was using a 165 degree (or thereabouts) non-sleeved
thermostat. Robert Shaw as I recall. So I wanted to get my engine up to
185-190 degrees sooner. I went with one of the same AC sleeved thermostats
82 degrees centigrade from Kees that Steve used. The engine seems to be much
happier and gets to running temp more quickly.

At least for my engine, a 160-165 degree thermostat keeps things cool too
long. In a perfect world I would prefer David Nock's bellows thermostat but
with a 185-190 degree opening. Since that doesn't seem to be available I
think I will stick with the AC unit and keep my eye on the temp. Gauge.

I am no authority on this. I am simply passing along my experience. Am I
understanding all of this correctly? 

Thanks,
Lin

Sent from my iPhone

On Sep 15, 2018, at 9:30 PM, Rossm <rvmaylor at shaw.ca> wrote:

To be fair Michael, it is hot maybe three days a year in Canada?:) .  I left
Calgary yesterday for the Rendezvous and it was snowing already. First time
the hood contraption on the BN6 has been up since last September.  

Sent from my iPhone

On Sep 15, 2018, at 10:50, Michael Salter <michael.salter at gmail.com> wrote:

Well I have watched this discussion on sleeved thermostats for the last week
but now I just have to say. When the sleeved thermostats went NLA, about 45
years ago, we resorted to installing just plain old Stant 175 degree stats
and guess what ... not one complaint or comment on running hotter or
overheating and absolutely no sign of any symptoms of overheating on my own
BJ8 even in the hottest of ambient temperatures. It just didn't happen!!!
Just sayin'. M 
  _____  

From: Healeys <healeys-bounces at autox.team.net> on behalf of Rossm
<rvmaylor at shaw.ca>
Sent: Saturday, September 15, 2018 10:35:32 AM
To: Forum Healeys
Subject: [Healeys] Thermostats 

Three sleeved thermostats, one on the right 160 degrees, middle no idea,
left is a Smiths x85002s/86 (180F) and has failed open. 

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