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Is there enough material in the '70 water temp sender to machine it down?
Stupidly I overlooked the fitting of the original sized water temp sender when I changed the heads on my SBC. The heads came tapped 3/8" and the sender is 1/2"? So I fitted the sender into the inlet manifold and all was well but now I have changed the manifold and have pulled the same stunt again:-( The Weiand manifold has only one tapping for 1/2" for the heater hose the other is 3/8"
So my question is will the sender thread down to 3/8" without damage? This would be an easier option than pulling the manifold again.
According to Lectric Ltd I should have this one but what I have looks the same but has a spade terminal and reads 20 deg optimistic according to the IR gun.
I think it would be easier to tap the 3/8th fitting in the manifold out to 1/2 NPT. a bubba-ish option would be to put a 3/8th nipple in and thread a 3/8 to 1/2 adaptor (bushing they call it) and put the heater hose over it. you wouldn't want to adapt the 3/8 hole with fittings and put sender in that cuz the sender would be in a side pocket with little to no flow, so it would read low. also it would look really stupid.
I think it would be easier to tap the 3/8th fitting in the manifold out to 1/2 NPT. a bubba-ish option would be to put a 3/8th nipple in and thread a 3/8 to 1/2 adaptor (bushing they call it) and put the heater hose over it. you wouldn't want to adapt the 3/8 hole with fittings and put sender in that cuz the sender would be in a side pocket with little to no flow, so it would read low. also it would look really stupid.
Searching this forum will reveal a couple of OTC options that give a close but not quite accurate reading.
I myself also added a Wilcox adjustable potentiometer to make the gauge accurate. It allows you to buy just about any sensor and adjust.
Last edited by Dynra Rockets; 12-15-2017 at 05:55 PM.
Willcox used to turn down the senders. They tapered them and then threaded to 3/8 npt. I think they found that if they didn't taper them before threading the sender would break while the threads were being cut. Me, I re-threaded the hole in the head to 1/2".
Stupidly I overlooked the fitting of the original sized water temp sender when I changed the heads on my SBC. The heads came tapped 3/8" and the sender is 1/2"? So I fitted the sender into the inlet manifold and all was well but now I have changed the manifold and have pulled the same stunt again:-( The Weiand manifold has only one tapping for 1/2" for the heater hose the other is 3/8"
So my question is will the sender thread down to 3/8" without damage? This would be an easier option than pulling the manifold again.
According to Lectric Ltd I should have this one but what I have looks the same but has a spade terminal and reads 20 deg optimistic according to the IR gun.
Stupidly I overlooked the fitting of the original sized water temp sender when I changed the heads on my SBC. The heads came tapped 3/8" and the sender is 1/2"? So I fitted the sender into the inlet manifold and all was well but now I have changed the manifold and have pulled the same stunt again:-( The Weiand manifold has only one tapping for 1/2" for the heater hose the other is 3/8"
So my question is will the sender thread down to 3/8" without damage? This would be an easier option than pulling the manifold again.
According to Lectric Ltd I should have this one but what I have looks the same but has a spade terminal and reads 20 deg optimistic according to the IR gun.
Tap the head 1/2" NPT. It's done all the time. Just be sure to tap SLOWLY and check the fit of the sender often. You don't want to tap it too big. And use a good thread cutting oil to prevent thread galling.
i think that lathe costs more than a drill bit and half inch pipe tap...
I have a lathe but limited threading skills, I'm looking for a 3/8 NPT die but may be quicker and easier to farm this job out to the local machine shop:-)
I used that adjustable resistor to dial in my gauge and it reads accurately for the first time (like ever).
Hi Carriljc I was not aware of the adjustable resistor, so thanks for the info. So I will turn down the sender I have and then add the resistor later, I know the sender I have makes the gauge read 20 deg too high but rather that than too low!
I make the 3/8 NPT sender out of the aftermarket senders....
But... I had to switch away from the LL sender, for some reason they started breaking in the lathe and when cutting the threads. My guess is the wall thickness changed about 6 months ago I'm really not sure.
I never had an issue with theirs before but they just kept snapping off. (And, there is no oil inside their sender...) I'd take LL parts over any other manufacturer 99.9 percent of the time but I switched suppliers on the senders. It was taking me two and three to get one good one.
If you are turning an original sender you'll not have any issue and the TU5 (wells unit) will work too.
12-15-2017, 05:31 PM
Is there enough material in the '70 water temp sender to machine it down?
