thermostat

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thermostat

#1 Post by new to this »

What size thermostats do most people use on a Sprint ?

Thanks Dave
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TrustNo1
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Re: thermostat

#2 Post by TrustNo1 »

there's only one size that will fit.
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Okay

#3 Post by sprint95m »

new to this wrote: Mon Oct 26, 2020 7:51 pm What size thermostats do most people use on a Sprint ?

Thanks Dave
Is this for your EFI Sprint Dave?
I guess you’re looking for a remote thermostat?

I will now run an 88 degree thermostat all year round,
but Sprints had a 82 degree one normally.

The 82 is a pain because during the winter the gauge won’t go much over 1/4,
whereas with an 88 it sits at halfway whatever the season happens to be.



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Re: thermostat

#4 Post by GrahamFountain »

I also use an 88C thermostat which normally read 1/4 on the previous gauge and reads 1/2 on the one that's in at the moment. That's with the same sender and voltage stabilizer BTW.

Graham
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).
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Re: Okay

#5 Post by new to this »

sprint95m wrote: Mon Oct 26, 2020 9:16 pm
new to this wrote: Mon Oct 26, 2020 7:51 pm What size thermostats do most people use on a Sprint ?

Thanks Dave
Is this for your EFI Sprint Dave?
I guess you’re looking for a remote thermostat?

I will now run an 88 degree thermostat all year round,
but Sprints had a 82 degree one normally.

The 82 is a pain because during the winter the gauge won’t go much over 1/4,
whereas with an 88 it sits at halfway whatever the season happens to be.



Ian
Thanks,ill get an 88 degree stat
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Re: thermostat

#6 Post by new to this »

GrahamFountain wrote: Mon Oct 26, 2020 9:26 pm I also use an 88C thermostat which normally read 1/4 on the previous gauge and reads 1/2 on the one that's in at the moment. That's with the same sender and voltage stabilizer BTW.

Graham
Im planing on using a MG oil/temp gauge,the temperature gauge is a Capillary tube so hoping it should be more accurate

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Re: thermostat

#7 Post by new to this »

TrustNo1 wrote: Mon Oct 26, 2020 8:52 pm there's only one size that will fit.
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I meant size, as in temperature rating
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Re: thermostat

#8 Post by GrahamFountain »

new to this wrote: Mon Oct 26, 2020 10:36 pm
GrahamFountain wrote: Mon Oct 26, 2020 9:26 pm I also use an 88C thermostat which normally read 1/4 on the previous gauge and reads 1/2 on the one that's in at the moment. That's with the same sender and voltage stabilizer BTW.

Graham
Im planing on using a MG oil/temp gauge,the temperature gauge is a Capillary tube so hoping it should be more accurate

Dave
Not sure accuracy is that important so much as consistency, so know when sumert's up.
I have a pair of thermometers one in either end of the rad with displays on the dash for more accurate monitoring while I was setting up the fan controller. Don't need them now, but haven't got round to removing.

Graham
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).
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Re: thermostat

#9 Post by new to this »

GrahamFountain wrote: Mon Oct 26, 2020 10:42 pm
new to this wrote: Mon Oct 26, 2020 10:36 pm
GrahamFountain wrote: Mon Oct 26, 2020 9:26 pm I also use an 88C thermostat which normally read 1/4 on the previous gauge and reads 1/2 on the one that's in at the moment. That's with the same sender and voltage stabilizer BTW.

Graham
Im planing on using a MG oil/temp gauge,the temperature gauge is a Capillary tube so hoping it should be more accurate

Dave
Not sure accuracy is that important so much as consistency, so know when sumert's up.
I have a pair of thermometers one in either end of the rad with displays on the dash for more accurate monitoring while I was setting up the fan controller. Don't need them now, but haven't got round to removing.

Graham
Graham

What setting did you set your fan to ?

Dave
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Re: thermostat

#10 Post by GrahamFountain »

new to this wrote: Mon Oct 26, 2020 10:52 pm
What setting did you set your fan to ?

Dave[/color]
That's a bit of a long story. But the simple answer is, on a static test, it comes on about 95C at the hot end and goes back off about 92C. I can set the on temp where I like and set the difference separately, but I like to set the two numbers as close together as I can without the relay jittering as it turns off. You might argue that having the fan go on and off more is stressful for it, but I think having it on for less time is better.

But, despite me knowing that I should have the sensor in the bottom hose, I left the switch in there as a reversionary option and put the sensor in the top hose (where the switch had once been) to set up. While the switch didn't work well in the top hose (and worked better with it in the bottom) the sensor in the top hose with the controller I built seem to work well enough that I'm not stressed about moving it.

I still believe the sensor should be in the bottom hose so the fan is controlled by the temperature of the water going to the engine, the temperature of that water is determined by the cooling from the rad (by fan or motion driven airflow), and the temperature of the water going to the rad is controlled by the thermostat (if a bit slowly). I don't think I want to try using the fan to control engine temperature as it only has any effect when there's no airflow through the rad from motion. Hence, in most cases, it's still the thermostat that's controlling engine temperature.

But I have to admit that, until the fan failed in the peculiar way it did (coming on fine then slowing after a min or two) and it boiled over a couple of times (at about 105C on the hot end thermometer), having the sensor in the top has worked well enough, just not as well as might be possible.

I did replace the switch in the bottom hose with a sensor the same as that in the top when I replaced the fan a while back. But between the lack of motivation, other stuff, and the rain, I haven't got round to using it. I should put the reversionary switch in somewhere as well, as that would be useful if the controller I built fails. So those are other reasons for not taking the thermometer's out just yet.

Graham
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).
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Re: thermostat

#11 Post by dursley92 »

I am trying out one of these Superflow ones just out of interest, though it sounded like a good idea - if a bit expensive.


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Re: thermostat

#12 Post by new to this »

dursley92 wrote: Tue Oct 27, 2020 2:10 pm I am trying out one of these Superflow ones just out of interest, though it sounded like a good idea - if a bit expensive.


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Ive seen those,they are dear is there any difference ?
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Re: thermostat

#13 Post by Carledo »

new to this wrote: Tue Oct 27, 2020 5:26 pm
dursley92 wrote: Tue Oct 27, 2020 2:10 pm I am trying out one of these Superflow ones just out of interest, though it sounded like a good idea - if a bit expensive.


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Ive seen those,they are dear is there any difference ?
Are you being intentionally obtuse Dave? The difference is clearly visible in the pics, the Superflow one has a central opening disc about 50% bigger than the standard one.

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Re: thermostat

#14 Post by new to this »

Carledo wrote: Tue Oct 27, 2020 8:25 pm
new to this wrote: Tue Oct 27, 2020 5:26 pm
dursley92 wrote: Tue Oct 27, 2020 2:10 pm I am trying out one of these Superflow ones just out of interest, though it sounded like a good idea - if a bit expensive.


Image
Ive seen those,they are dear is there any difference ?
Are you being intentionally obtuse Dave? The difference is clearly visible in the pics, the Superflow one has a central opening disc about 50% bigger than the standard one.

Steve
Your jumping the gun a bit there,the original sell says there a better flow rate,thats why i said is there any difference

Dave
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Re: thermostat

#15 Post by GrahamFountain »

The higher maximum flow rate means that the average temperature of the radiator would be higher, since the hot water would get further across. Hence, it can dump more heat for a given pump rate and airflow. But I don't think this is going to make a huge difference to flow through the radiator - certainly not 50% more - as the run of pipe and the radiator itself will have much more effect on limiting flow than a short restriction like a fully open thermostat. There are too many unknowns to evaluate it, but do I know that taking the thermostat out entirely won't have that much effect on the maximum flow through the rad - just makes it the maximum all the time.

Also, when the heat being generated is in the normal range, it won't matter at all, because the two thermostats will be allowing the same flow. So, it's just that the thermostat with the bigger orifice can still maintain control of engine temperature at a slightly higher level of heat generation, presumably from a higher power output.

So, for a normal road car, in normal conditions, it might help a bit if you have an overheating problem. But that raises (not begs) the questions, why do you have an overheating problem and shouldn't you fix that first?

Graham
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).
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