Engine Temperature Measurements

[PEZBerq]

I am considering using waterless coolant in my magnesium barrel 1987 Husky 4 stroke. I want to watch the engine cylinder external surface temperature and would like to use those temperature indicator stick on labels for easy checking anytime without needing a temperature gun or other instrument handy. Does anyone know where you can buy those over the counter? What temp range would be best for normal operating temp of a four stroke. Cheers

[Tim754]

Industrial specialist welding suppliers, Specific preheating temp strips.

[evo550]

These things?
http://www.ebay.com.au/itm/Pro-Circuit-Thermostrip-Temperature-Strip-3-Pack-/370734476393?pt=Motorcycles_Parts_Accessories&hash=item56517f2c69

[PEZBerq]

Exzachary! Found some that have Celsius on them instead of foreign height  Factory FX have them. Not sure if they are one shot use (record max temp reached only) or reset once the bike has cooled and will give a reading each time like a thermometer.

[evo550]

Yeah, I was going to say you should be able to get 'em at most bike shops here.
Me thinks they work like a thermometer and change colour as the bike heats up and cools down, you see them all over the place at modern events. Apparently they increase power by up to 7 hp across the rev range , when combined with a Metal Melisha sticker kit.

[Montynut]

Does measuring the cylinder temperature on the outside really tell you anything much about the cooling of the cylinder internals?

The exterior is directly affected by ambient conditions such as air temperature, shade versus full sun even air circulation. It will give you an idea but not really anything solid to go by. Maybe monitoring the radiator body temperature at the inlet may give you a better indication but still only an inferred value.

From my instrumentation background external temperatures are often very misleading when a cooling system is operating. An example is that a coolant that is more effective will conduct heat better and may actually increase the external surface temperature as it pulls heat out of the hot inner surface.

The devices you are suggesting are used in a static situation for a heat soak environment such as pre-heating for welds or mesuring maximum temperature that a spacific device reaches not trying to monitor the effectiveness of a cooling medium by measuring a remote surface affected by things other than the coolant.

[Lozza]

What is waterless coolant? Those stickers are a waste of $30 a laser pointer would last longer for the same price. If you wanted some meaningful real time data a CHT probe is the way to go

http://thesensorconnection.com/egt-probes/meter-kits/cht-sensor-kit-race-series-ws

[Montynut]

I hate to spoil everyone’s party on the heat sensor guns. They are very very much over rated and are used in industry just as basic guide not for diagnosis. The famous laser spot has nothing to do with the guns reading it is just a general aiming device. Read the specs of the device and you will find they take the average temperature of an area which is dependent on distance. For example a temp gun will take a read at 30cm from a surface and averages the temperature over something like a 150mm circle or reads the temperature of anything in between the gun and the target like an exhaust pipe. If you increase the read distance to 60cm the averaging area is enlarged by a squared function.  Yet the little laser dot is still the same they also will not read accurately much closer than 15cm.

We have a temperature device which gives you a thermal image and when you compare this to the temp gun you see instantly the shortcomings of the temp gun. People all the time tell us our $3K temperature sensors are wrong because their $100 temp guns says this or that. There credibility is instantly destroyed.

Temperature guns are OK to tell you the average temperature of say a slick race tyre but a tyre tech will use a direct reading probe every time which actually has a small penetrating probe to eliminate surface issues etc and gives the temperature gradient across the tyre.

Lozza is correct the only reliable way is to have a direct reading sensor to measure the coolant temperature..

[pancho]

   I would expect that an oil temp gauge would be the most reliable.

   Coolant temperature gauges can supply highly fluctuating readings, especially during warm up and/or with flutuating ambient temperature.

       Correct positioning of the sensor is critical.

 pancho.

[Lozza]

Who tunes an engine with oil temp? Thermostats take care of temp fluctuations, if your cooling system fluctuates wildly with ambient temp changes you simply don't have enough cooling capacity.

[pancho]

Who tunes an engine with oil temp? Thermostats take care of temp fluctuations, if your cooling system fluctuates wildly with ambient temp changes you simply don't have enough cooling capacity.

That depends on the type and quality of the thermostat and the location of the thermostat and the design of the circulation system including coolant capacity.
 
Thermo syphon with pump assist, or fully pump driven circulation.
 
 Other design features include coolant viscocity and boiling point, designed operating temperature and cooling system pressure.

[chrisdespo]

Temp guns are a good tool i just takes time to learne them corectly Montynut is right but they can be used for diagnosis in a gereral way. for what you want to do get a dedicated guage to read the coolant temp it realy makes no differance what sort of coolant you use water, glycol, oil as long as you set everything up to handle it, the bike manuacturer would probably spent a fair amount of developement bucks on designing and testing the cooling system and i tend to stick to their specs on every peice of equipment that i work on from saws mowers and stuff all the way through to earth moving plant. Petrol and Diesel and everything inbetween

[Tim754]

Sometimes me only having only air cooled* machines looks a great idea

*Do have so accessory oil coolers that are air cooled fitted, but hey prior to that used to change the oil after every 50 minutes running, Now after every 120 minutes.
 Oil is cheap compared to sourcing and replacing engines