I'd like to add a head temp sensor to my 2 liter motor, i have the motor out of the car now, I like the idea of the spark plug gasket thermal couple, but it appears there is little room around the plug hole to get the wire out. Do you all grind away some of the metal on the head to install one, and if so which side is best to grind?

Also what are typical max. safe temperatures for the head?


thanks d ave

I have a cyl. head temp gauge installed on my 2.0, its connected to the 3rd cyl. The sending unit just slips over the plug and you install the plug with the sending unit. You can bend the sending unit 90 degrees having it coming out the tin vertical. I didn't have to grind anything it fit in the plug hole with no problems.

My head temp is usually at 350 degrees, it will go up when going up hills. I guess if it gets up to around 400 degress its time to start worrying. 375 and I'm worring.

The plug is the only place for the thermocouple. Anywhere else will give a crappy reading that can be 100-200 deg low!

The wire can be carefully bent and brought out around the plug wire- no sweat..

300-325 is optimum for a good comboed engine. Most stockers always run 350-365 and hit hills at 375-400. 400 is fine for short times... Start worrying at 410 or so at 425 you are in the area to have a dropped seat.

Bigger engines run cooler if configured correctly- FYI

Jake,
Is the stock sender on cyl #4? Is there a preferance for which one?

The stock sensor was on #3! BUT the factory designed that location not to be at head temperature and only to let the brain know if the engine was hot or cold- not a definite temperatyure.

I tested this during my cooling system test and found that the stock position would never go above 220 degrees. It did however stay hotter longer when the engine shut off, so the car could be restarted after a few minutes and not go rich on the FI...

I have written a very uin depth tech article that will be up on my site as soon as we are ready to blast away with the updated version.. about 2 months out.

so, on a carb'd car, does it really matter which cyl you use?