B20 build

[arcturus]

check that you don't have an air lock. Also having the heater on will increase the amount of coolant circulating.

[jimbo1593]

Lower temp stat for electric fan?
Or adjustable solution?

I have an adjustable revotec unit plumbed into lower hose on mine, minimum adjustment and still didnt come on. Would put this unit in top hose next time, i know it' supposed to be lower, but can't be bothered wiring in new resistors into the potted potentiometer housing. I never liked the in elegance of this so changed to a 240 plastic fan.
A tapping into the core for oem temp switches to control elec fan would be lovely.

[Ron Kwas]

Jimbo;

Tstat sets engine temp, and does not affect Cooling Sys effectiveness!

There has been some discussion on location of Temperature Sensor for Elec Cooling Fan ...my recommendation is to locate Sensor to monitor Coolant temp at the output side of Rad...so at the bottom. In this way, the ECF will be able to augment Rad heat-shedding when Rad output temp rises such as during hi load, or slow travel and accompanying poor airflow through Rad. With thermostat open, and Sensor mounted in upper hose, Sensor would always see a hot condition (and ECF would be on continuously, maybe needlessly) since coolant coming from engine will always be hot.

Idea is to sense if coolant is returning from Radiator insufficiently cooled and turn ON ECF to improve cooling effectiveness of Radiator when necessary. Sensor should be adjustable to allow characterizing the system and selecting a turn-ON point, but once that is set, I wouldn't expect to have to muck with it too often.

Cheers

[Derek UK]

The temp adjuster switch should have a very wide range. The Kenlowe one can be adjusted to come on even before the temp gauge reaches normal running temp. At the other end of the range it can be set to come on when the temp gauge is well into the red, which is too far. Just run the engine until it's normally hot and then set the switch to switch the fan on when it starts to rise beyond that. With current weather/temps of about 10º it might not get high enough to switch on even after a VERY long idle if the whole cooling system is in a good state.

[jimbo1593]

Ron,
I meant the thermostat for the electric fan, rather than the stat to open flow to the radiator; should probably have writen thermistor for clarity.

I agree the positioning of the temp switch should be lower hose for the reason Ron states, but on the revotec unit the temp will not adjust any lower to come on at lower temp, hence why if I was still using this unit I would put it in the upper hose.
The upper hose will always see water hotter than the stat opening temp, but the temperature range in the top hose will vary from barely opening 72deg to "too feckin" hot in the red (white). The top hose can be used for a temp switch as long as it adjusted appropriately.
I would doubt that 75deg water that has gone through a rad with air passing through at 70mph would heat up to 90deg no matter what tune of engine, however water at 75deg passed through a rad with no air flow may well heat up beyond the lower threshold on the temp switch and thus turn on the fan.

Originally Posted by Ron Kwas

Jimbo;

Tstat sets engine temp, and does not affect Cooling Sys effectiveness!

There has been some discussion on location of Temperature Sensor for Elec Cooling Fan ...my recommendation is to locate Sensor to monitor Coolant temp at the output side of Rad...so at the bottom. In this way, the ECF will be able to augment Rad heat-shedding when Rad output temp rises such as during hi load, or slow travel and accompanying poor airflow through Rad. With thermostat open, and Sensor mounted in upper hose, Sensor would always see a hot condition (and ECF would be on continuously, maybe needlessly) since coolant coming from engine will always be hot.

Idea is to sense if coolant is returning from Radiator insufficiently cooled and turn ON ECF to improve cooling effectiveness of Radiator when necessary. Sensor should be adjustable to allow characterizing the system and selecting a turn-ON point, but once that is set, I wouldn't expect to have to muck with it too often.

Cheers

[jimbo1593]

The Kenlowe one might, but the Revotec one doesn't ;-)

Originally Posted by Derek UK

The temp adjuster switch should have a very wide range. The Kenlowe one can be adjusted to come on even before the temp gauge reaches normal running temp. At the other end of the range it can be set to come on when the temp gauge is well into the red, which is too far. Just run the engine until it's normally hot and then set the switch to switch the fan on when it starts to rise beyond that. With current weather/temps of about 10º it might not get high enough to switch on even after a VERY long idle if the whole cooling system is in a good state.

[Quarterless]

Having the sensor in the top hose gives you a true reading of engine temp and so enables a faster response by the fan to temperature changes. Kenlowe adjustable fans specify this placement for the sensor for this reason. I have one in front of my standard rad and have never had an overheating issue. I would be concerned if your setup is overheating as an alloy rad should give you a significant cooling improvement over standard. Was your engine hot with a standard rad? Is your alloy rad from a decent source? You can get additional temp issues if your engine is running lean. Have you checked for intake air leaks or leaky spindles? This can be checked by spraying easy start at the spindles etc. If the engine picks up you have s leak. Don't over egg it though or you might cause s fire.

[Amazonjulian]

Thanks for all the interest. Mixture is spot on judging by the plugs and the carbs have been rebuilt eliminating the spindle issue. Have invested in a laser thermometer so will be looking at temp in and out of rad. I'll report back