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 Posted: Oct 24, 2019 10:57AM
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Quote:
Originally Posted by Dan Moffet
I found my engine (1275 high compression Metro ) always ran cold when I had 6 - 1/8" holes in the thermostat. I replaced it with one free of modification, even though it does not have the pump by-pass hose. I find the engine heats quickly and the t'stat opens smartly once the head is warmed up. Contrary to popular belief, the head doesn't overheat because the coolant in it would have to boil severely for that to happen, but the heat spreads to the t'stat and it opens long before that would happen. This is with the heater valve closed or open.  Now my heater actually produces... heat!
Don't know the reason for drilling the holes in the t'stat.  I've been told that it helps to keep the #4 cylinder from overheating-selective coolant circulation in the head??  Calver recommends 6-8 1/8" holes but I don't recall the reason.  Vizard recommends drilling two 1/4" holes to keep coolant circulation if the t'stat fails to open-makes more sense.  Another knowledgeable person says to just let the t'stat do its job without the holes.  As I mentioned, this engine has always run on the cool side and has always had a drilled t'stat.  Cooler weather has arrived, guess I'll give a try to one without  the holes and see what happens.  I'll keep you advised.

 

"To catch one, you need one"....John Cooper

 Posted: Oct 22, 2019 10:17AM
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CA
I found my engine (1275 high compression Metro ) always ran cold when I had 6 - 1/8" holes in the thermostat. I replaced it with one free of modification, even though it does not have the pump by-pass hose. I find the engine heats quickly and the t'stat opens smartly once the head is warmed up. Contrary to popular belief, the head doesn't overheat because the coolant in it would have to boil severely for that to happen, but the heat spreads to the t'stat and it opens long before that would happen. This is with the heater valve closed or open.  Now my heater actually produces... heat!

.

"Hang on a minute lads....I've got a great idea."

 Posted: Oct 22, 2019 10:07AM
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Quote:
Originally Posted by malsal
Have you actually verified the temperature or are you just going by the gauge?

If you have verified it for peace of mind just replace it with a 195 degree one and see if it makes a difference, they are cheap enough and easy to change out.
Yes, temp was verified using an infared thermometer.  Pretty close.  I have six 1/8" holes drilled in the perimeter of the thermostat, perhaps that could be affecting the function.

 

"To catch one, you need one"....John Cooper

 Posted: Oct 21, 2019 07:30AM
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For reference, Vizard covers engine temps in the yellow book, chapter 20 in my version.

For maximum horsepower 160/70 is best. However at that temp the oil will be contaminated by combustion by products requiring 1000 mile oil changes. Optimum oil temp is 212/100 and 225/107. With an 185/85 coolant temp, oil changes can be extended to 3000 miles.

He has lots of other anecdotes scattered throughout the book which make them harder to find.

Our oil temp on the way home was only up to 176/80. We have no cooler, so I have often wondered what oil temps people are seeing that suggests the use of an oil cooler is required these days.

 Posted: Oct 21, 2019 07:13AM
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Yesterday we had our local MOASF car show. We left around 7:00 Am to go to the show and the outside temp was 50F/10 C. Once on the freeway the car was running 158 F/70 C. Too cold for my liking. Even on the way home when the outside temps were 70/21, the car only managed 167/70. This is with the 195/90 thermostat. I have tried a number of them, even the more expensive versions and they all have the same characteristics. Some open sooner and others stay open longer.

 Posted: Oct 19, 2019 03:59PM
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My target has been 180, but I will look for Vizard's info. In his yellow book he also mentions oil temps, but I can never find the section when I want to.

 Posted: Oct 19, 2019 03:44PM
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The best running temperature was explained in detail by David Vizard in one of Mini World's, Keeping Your Mini alive. 

 Posted: Oct 19, 2019 12:39PM
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I have had a number of failures with Smith mechanical gauges while trying to get a handle on running temps. My engine setups are a little unique and may not apply to others. I am trying some new Smith electronic gauges for both oil and coolant temps.

I have been running a 195 in the cabureted engine and it seemed to work well over the 5000 miles we did during the summer. With the weather cooling off, it seems to be running cool around town now.

As an experiment I have been running a 205 in the fuel injected engine and it did fine all summer, but we did not take that car on any extended trips with hot summer temps. I am not sure the 205 has the head room if we run into 100 F ambient temps climbing under load.

I would like to find a 200 thermostat, but I am not able to find one to try. The thermostats are the same as small block chevy, so you think they would be available somewhere.

The engines are MPi blocks that are almost identical with side mounted radiators, one with an HIF 44 and the other with the SC injection kit. As I said my results may not apply. It seems the MPi block runs cooler than a standard block.

I also discovered that many of the infrared digital thermometers have a limited accuracy, something like +/- 5 to 10 degrees.

 Posted: Oct 19, 2019 08:17AM
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Have you actually verified the temperature or are you just going by the gauge?

If you have verified it for peace of mind just replace it with a 195 degree one and see if it makes a difference, they are cheap enough and easy to change out.

If in doubt, flat out. Colin Mc Rae MBE 1968-2007.

Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.

 Posted: Oct 18, 2019 07:32PM
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Sounds good to me. The reason I asked is that my car has always run on the cool side using a 180 so I was considering going to a 195 ‘stat.  

 

"To catch one, you need one"....John Cooper

 Posted: Oct 18, 2019 03:16PM
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I always run a 180 degree thermostat in a carbed street Mini.

FI cars seem to be set to run hotter so they may run 195 or thereabouts.

If in doubt, flat out. Colin Mc Rae MBE 1968-2007.

Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.

 Posted: Oct 18, 2019 10:24AM
 Edited:  Oct 18, 2019 01:03PM
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I posted this question on another forum in the UK and didn't get much of an answer so I'll throw it out to you guys.  Considering ethanol 'enhanced' fuel is everywhere and the A series engine's combustion chamber efficiency, what would be the target coolant temperature/thermostat for a moderately enhanced street engine?  180?  195?  200?

Edit;  For what its worth, a response from the UK was posted later that explained it pretty well.  To summarize, 160 degrees too cold for street use-doesn't allow oil to get hot enough to burn off contaminates in the oil.  192 best for emissions and 180, the best of both worlds.

 

"To catch one, you need one"....John Cooper