Water temp sensor for AFR heads.....
 

OK, OK, I know there was a thread just a couple weeks ago and others in the past. My search efforts have yeilded great amounts of frustration and very little hard info. Sorry.
I'm changing out my '73 small block OEM iron heads to AFR 180s. The OEM water temp sensor has 1/2" NPT threads. The AFRs need 3/8" NPT. My OEM sensor calls out to be 80 ohms @ 220 degrees. So far, no luck at parts counters or the web. Got e-mails in to NAPA, Borg-Warner, and Stewart-Warner, but no replies yet.
My Wieand manifold has only one 1/2" tap, I need that for my heater hose. My guages are all stock and work fine, I'm not going to change them. I don't want a big cobbled-up bubba adaptor on the engine. I would prefer to not have to put a resistor in the wire to adapt the ohms, but I will if that's the only way.
I've looked for the Borg-Warner Volvo unit #WT510 and the Standard #TS76 but could not find the ohm rating, so am leery of getting one of those on a "maybe".
Anybody ever come up with something conclusive?
Thanks,

John

I put a WT510 sender in my vortec heads and also left the stock 1/2" sender in place by the thermostat so I could compare the two. The 510 works OK but will make the guage go into the red for a while until settling down where it reads about 20 degrees warmer than the stock sender. So I haven't decided for sure what to do yet but I really hate the stock sender right below the upper hose.:ack: I guess the 510 would still alert me to a problem if there is one so I'll probably stick with it.

You need to use the stock style sensor if you're using a stock style guage.

There is a 1/2 to 3/8 pipe plug adapter that you can use. Or I can send you my old one if you can't find one. I used it for about 1200 miles and it worked fine.

Now my temp sensor is just mounted in my intake manifold. Works just as good if not better. :thumbs:

jd,
What do you do for your heater hose connection?

torq,
I can come up with some kind of adaptor to get my 1/2'" male into a 3/8" female I'm sure, I just want to avoid a big, well, uh, dildo-looking thing hanging off the side of my block. Plus I don't want to have to remove it and spill coolant all over when I remove/replace my headers....

Shoot, I gotta go now. Prob'ly be tomorrow before I can check back, but thanks--

John

I put the stock temp sensor in my intake manifold when I got my AFR's. It really does work just as well. If you want, you can have the 3/8" hole in the AFR's machined out to 1/2" as some have done. AFR will do this, if you if you order from them and let them know before they send your heads, or if you wish to send them back to have it done.

Without looking I believe I screwed a 1/2" NPT fitting with the hose barb on the other end into the thermostat housing. The other hose goes into the water pump.

Phil, it didn't look that bad. I spent an hour in my local auto parts store searching for a temp sensor with the same resistance for a 3/8 hole. No luck. I think you'll find the same. What kind of intake are you using?

Hey guys, think I got it worked out. I was approaching it from the wrong direction.....A friend at a shop gave me a water neck from a 72 Chevy truck which is identical to mine except for a 1/2" NPT tap for the OEM sensor in the top. I could use it for the sensor or heater connection, it would just have to wait for the water temperature to open the t-stat. Then when I got back home I realized my Wieand manifold has a 3/8" tap as well as the 1/2". Today I went to NAPA and got a 3/8" heater hose fitting. So now I can put my OEM sensor in the manifold 1/2" tap, the heater in the 3/8" tap, and have a "spare" 1/2" tap on the neck for a screw-in mechanical guage as well. I ended up plugging the 3/8" holes in the heads.
I be pooping in tall cotton now, I had just worked myself into a tizzy by not talking it over with friends before jumping to conclusions.....I will still be interested to see if the parts companies respond, and if they do, I'll post it.
Motor should be on the run stand Saturday, if all goes well. I'm excited.
Thanks for your replies,

John

why not just put a resistor in the wire line?

:iagree: :D

That may or may not work. I ran into a similar problem when swaping to the LS1. The only port in the head was only big enough for 1/8NPT.

You need to know more than just the resistance reading at a specific temperature. You also have to know the rate of change. Like how many Ohms for every degree change in temp. I found one sensor that was dead on around 210-220, but when installed in the car the meter barely came off the low peg. I actually got a little above 220 while working out some cooling bugs and the meter slowly came up to mid range then very quickly pegged high.

Like was said above. Use the correct sensor for the correct meter.

Reply from NAPA
 

Here's what NAPA sent to me. I guess I won't be able to verify it because, as you read above, the point is now irrelevant for me. I hope this may be able to help someone else...

John


"Thank you for visiting NAPAonline.com. The water temperature sending unit that you are searching for is available at local NAPA stores, and can also be ordered at NAPAonline. The part number is TS6641. To order a part online or obtain more information about it, at our home page scroll down to search by part number, insert part number and click Go. Follow the instructions and prompts on your screen.

Again, thank you for visiting NAPAonline.com.

Regards,

Customer Support"