138 temp sender location front or rear?

[Rooooboy]

Hi guys, after some advice, I recently purchased a ek with 138 grey. It’s been freshly rebuilt, it had a electrical water temp gauge at the rear port of the cyl head. Traditionally where the heater hose would go.

It has the factory idiot light sender at the front of the cyl head.

I noticed at idle the temp on the elec gauge would slowly increase to 100 if idling for 10min oh a relative cold day ambient 15degree.

I removed and recorded the radiator, as I didn’t know the history. At the same time I fitted a mechanical temp gauge where the idiot sender is fitted from factory. The Mechanixal gauge sits on 82degree. I also fitted a high flow stat then the radiator was out. 177f.

My question is is it normal for the rear of cyl head to get hot?

My next move is to swap sender positions and see if the mechanical at the rear gets to 100 like the electronic gauge?

Just after peoples experience.

Thanks

[Harv]

The rear cylinders run hotter. Great explanation here:
http://forum.fefcholden.club/index.php?topic=26399.0

There is a gasket available to fix the water mal-distribution issue. I've made three batches up so far. No plans for another batch at present, but probably will at some stage.

Cheers,
Harv

[fraze]

Hi Roooboy, I think you might have the water ports mixed up. The factory position for the water temp idiot light sender is the rearmost port, nearest the firewall. The front port is for the heater. An ancillary temp guage ideally should have its sender in the thermostat housing. If your engine doesn't have the port in the thermostat housing then either get one ( often on ebay) or fit a "T" at the rearmost port on the head where the idiot light sender is. I went through this exercise a while back. If your engine tends to overheat get the modified head gasket, they work! Cheers, Fraze

[In the Shed]

Hey Fraze
You must have the rare X2 Grey motor in your car. I believe the temp sensor was originally installed in he port closest to the generator with the rear port being used for the heater tap. This is how my Dads original FB is set.

Regards
Stephen

[Harv]

Be wary of using tees with temperature senders. The sender unit probe ends up out of the water flow, and will read cooler than the actual temperature.

OK to use tees on oil pressure senders as the pressure is equal inside all the tee.

Cheers,
Harv

[Rooooboy]

Update.

I fitted the mechanical gauge to the rear of cylinder head, and upon removal of the electric sender, I found the adaptor fitting used, didn’t allow the sender to protrude and measure a good reading.

With the mechanical gauge in the rear port it was idling perfect. Sitting on the thermostat. 77 degree.

I think I will stick to a mechanical gauge.

Thanks all.