I've read that it is common to cut down a stock sbc temp sender to fit the 12X1.5 threaded hole in the head. The sender I have is 1/2 npt and is quite a bit larger than the 12 mm hole. Can I safely remove that much material from the sender without messing anything up? And for my own understanding....what is inside the temp sender?.....How does it work?

 

I tried turning down an M14x1.5 sender to fit and it ripped in half when I tried to tighten it. Hard to imagine getting a half incher down to that size.

There is just a small electronic thermister, a hard piece of plastic with two electric leads, inside the hollow brass tube.

In fact, I have had a stock one twist in two with just slightly too much torque.

Your best option is to drill out the head and retap it or relocate it to a different spot. Lots of options for that.

 

I re-taped my head ti 1/2" NPT without any problems.

The temp sender has a small thermocouple inside it who's resitance varies with the temp of the water surounding it.

There aren't any moving parts inside.

 

Looking through the local salvage yard, I see that some of the 90's gm vehicles have a 3/8 npt sender. Could this be cut down and threaded to 12X1.5? I'd rather modify a sender than the head.

 

Contact LS1MCSS, i just got a temp sending unit lathed down to the proper thread specs and his pricing and shipping was great!!

 

I tapped the head to a size of one of the adapters that came with my mechanical guage.

 

I doubt you can turn down 1/2" to fit in the head. The drivers side brass block plug is the perfect size to drill the interior (allen head) and tap for 1/2" npt.

 

i tap'd my waterpump for my old camaro and truck and it work'd like a charm....

 

You are correct. The 1/2" senders won't turn down small enough. I tried an old one I had here and cut completly through it way before it was small enough. I start out with the 3/8 senders and cut them to 12MM.

 

How much for a sender?