C1 Reproduction Temperature Senders

[Ian G.]

Re: C1 Reproduction Temperature Senders

JDG and Rich M you are both the best!

[Richard M.]

Re: C1 Reproduction Temperature Senders

Rich With it all said and done for cars not being judged what sender would you buy? Also do all small blocks use the same sender?


Thanks Bob

Bob the Napa part would be my choice.
IIRC 58 TO 67 same. Earlier is different. Check application based on year.

[Richard M.]

Re: Fuel sending unit ohms 62 Corvette

Rich Would these numbers be the same for all C1 units?

Bob

Bob, 1956 used a different wire terminal configuration using a pin plug.



1957 to 1967 used the flat bladed terminal.


IIRC earlier pre-1956 C1's used a unique thermocouple mechanical sender/gauge. I've never played with those.

Rich

[John M.]

Re: C1 Reproduction Temperature Senders

Just a little footnote to this discussion. I have what I think is a KB reproduction sending unit in our C2, purchased from Zip. It seemed to be very accurate - but upon driving the car for more than 50 or 60 miles it developed what I guess would be called "thermal creep" and the temperature gauge begins to rise and will within a short time peg the temp gauge. Pretty unnerving the first time it occurred but a check with an IR gun proved the temp to be within the normal range. This has happened several times, so it was not just a fluke. Going to pitch the sender since an inaccurate gauge is worse than no gauge. Hope that soon someone will produce and market a TS unit that will pass NCRS judging AND be accurate. Hard to imagine that thousands of these units could be manufactured and sold with circa 1950 technology and last for more than half a century and in todays world no one can come up with one that passes muster. Is that possible? Sooo- if you have a reproduction sender that appears upon short periods of observation to be a true indicator of engine temp just be aware that at least one of them exhibits "mood swings" and loses its mind.

[Jim L.]

Re: C1 Reproduction Temperature Senders

but upon driving the car for more than 50 or 60 miles it developed what I guess would be called "thermal creep" and the temperature gauge begins to rise and will within a short time peg the temp gauge. Pretty unnerving the first time it occurred but a check with an IR gun proved the temp to be within the normal range. This has happened several times, so it was not just a fluke..

I've had two NAPA senders exhibit this thermal runaway phenomenon. I just live with it since I have the engine in my car instrumented with thermocouples and I can get an accurate engine temp by looking at the laptop computer.

Back to the thermal runaway: There is a pretty good amount of current passing through the sending unit in the course of its normal operation. As current passes thru the resistive element, it heats up. As it heats up, its resistance goes down and the gauge reading goes up. Of course as the resistance goes down, more current passes thru the resistance and it gets hotter. Rinse and repeat.

My SWAG is the resistive element isn't in good thermal contact with the brass housing. If it was, its temperature would be dominated by the temperature of the coolant flowing by it and there would be no self heating going on. Just a hunch but it makes sense to me.

Jim

[Jim D.]

Re: C1 Reproduction Temperature Senders

Just a little footnote to this discussion. I have what I think is a KB reproduction sending unit in our C2, purchased from Zip. It seemed to be very accurate - but upon driving the car for more than 50 or 60 miles it developed what I guess would be called "thermal creep" and the temperature gauge begins to rise and will within a short time peg the temp gauge.

That's exactly what the "super accurate" one from LL did in my car. I threw it in the trash where garbage belongs. K&B is the supplier to Zip and probably for LL as well.

[John M.]

Re: C1 Reproduction Temperature Senders

Called Zip today about faulty sender. They were great and credited my account . Very easy transaction and no drama whatsoever. Hats off to them !

[Gary J.]

Re: C1 Reproduction Temperature Senders

Probably wouldn't hurt to let the supplier know of the problem....

[Jim D.]

Re: C1 Reproduction Temperature Senders

Probably wouldn't hurt to let the supplier know of the problem....

In post #21, he states that he sells 1000's of them. No mention of how many end up in the trash or how many are actually happy with his product.

[Ken A.]

Re: C1 Reproduction Temperature Senders

Always good to hear non productive criticism, what did I do to deserve it?

[John M.]

Re: C1 Reproduction Temperature Senders

Ken, I certainly meant no harm to you or your product. The unit I had did not function correctly and Zip credited my account for the amount of purchase. I asked if they wanted the old unit and they did not. From that I assumed that either no one cared why the unit failed or (my real hope) that you already had done a failure analysis on many units and were aware of the problem and had or were going to rectify whatever was causing the crazy readings. I chose a credit since no one has come forth and said all was now well and the problems were corrected. So, I will gladly send you the part so you or your manufacturer can learn firsthand, or will be happy to receive another unit from you that has been corrected. Please let me know if that is acceptable. Again, no harm meant and I hope that you now have a suitable replacement available. Will be glad to provide my contact information if needed.

[Francis F.]

Re: C1 Reproduction Temperature Senders

Richard, is their a need for the teflon.and could it effect the performance ? just asking.
Francis

[Richard M.]

Re: C1 Reproduction Temperature Senders

Richard, is their a need for the teflon.and could it effect the performance ? just asking.
Francis

Francis,

I do not use, nor do I recommend, the use of Teflon Tape. However I do use a paste type thread sealant. When I use the sealant I always apply just a small amount at the bottom perimeter of the sender or pipe fitting and clean any excess away to emulate a original installation, which did not use sealant.

It has never created a contact issue as the threads bite into the manifold creating a proper ground. I often use a ohm meter to verify proper ground after installation. I have never seen higher resistance.

Also, in my experiences, it is necessary to use the sealant as the threaded locations for sending units and pipe fitting on 40 to 50 year old manifolds are not as clean as when they were new.

Rich

[Joe L.]

Re: C1 Reproduction Temperature Senders

Francis,

I do not use, nor do I recommend, the use of Teflon Tape. However I do use a paste type thread sealant. When I use the sealant I always apply just a small amount at the bottom perimeter of the sender or pipe fitting and clean any excess away to emulate a original installation, which did not use sealant.

It has never created a contact issue as the threads bite into the manifold creating a proper ground. I often use a ohm meter to verify proper ground after installation. I have never seen higher resistance.

Also, in my experiences, it is necessary to use the sealant as the threaded locations for sending units and pipe fitting on 40 to 50 year old manifolds are not as clean as when they were new.

Rich

Rich-----

Yes, thread wear/erosion in the manifold or cylinder head may require the use of some sealant applied as you describe.

However, the threads in the manifold/heads as well as those on the temp sender are NPTF, not NPT. These threads were originally designed to seal without the use of any sealant. GM refers to this type of thread as "Dryseal".

[Francis F.]

Re: C1 Reproduction Temperature Senders

Richard and,Joe,thanks for your reply. this info adds additional knowledge to me and all members,
(NPTF/ and "Dryseal ")good stuff.
Francis