Temperature Sending Unit BB
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 751
Likes: 0
From: Chandler AZ
St. Jude Contributor
Temperature Sending Unit BB
I installed an new temperature sending unit on the freshly rebuilt engine. It looks like it might be off slightly on the cooler side. I took my original sending unit and measured 600K Ohms and then the new one in the car 50 Ohms. Something is not right.
Can someone measure the sending unit tip to block/gnd and get me a reading on a cool engine?
I am thinking I may have the wrong sending unit but physically its correct.
Can someone measure the sending unit tip to block/gnd and get me a reading on a cool engine?
I am thinking I may have the wrong sending unit but physically its correct.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
I can not give you the data you request...BUT...from experience. The sending units made today are NOT as closely monitored as the ones GM made when you are was built. GM had them held to tight tolerances when manufactured. And when I talk to my gauge restorer...the ohms get really close in value when you get on the upper temp range and this is where you can have an issue. I have had some that were 100 degrees off...seriously...brand new and it would spike up at a certain point.
SO..if you still have a problem....what I do is send the temp gauge cluster to him with the temp sending unit that I am using and he 'dials it in' so when the temp is at 180 degrees ( for example) it is at 180 degrees on the gauge. Basically I get it set to the temp that is at the 12 o'clock position on the gauge...so it can be 180, 200 or 210 degree F. AND the temp sending unit is for that gauge and any other temp sending unit will more than likely not be correct. I have had 3 temp sending units that were all different. I will leave the suppliers name out of it.
DUB
SO..if you still have a problem....what I do is send the temp gauge cluster to him with the temp sending unit that I am using and he 'dials it in' so when the temp is at 180 degrees ( for example) it is at 180 degrees on the gauge. Basically I get it set to the temp that is at the 12 o'clock position on the gauge...so it can be 180, 200 or 210 degree F. AND the temp sending unit is for that gauge and any other temp sending unit will more than likely not be correct. I have had 3 temp sending units that were all different. I will leave the suppliers name out of it.
DUB
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 751
Likes: 0
From: Chandler AZ
St. Jude Contributor
Ouch that's real ugly DUB. Lets see if anyone can help me out with a cold reading. I also will get the engine warmed up and put the old sending unit on the manifold and measure both "hot" resistance. I am sure they will be off.
Maybe I am just looking for a vendor that sells a quality replacement. I doubt that there are "tight" tolerances. Its just a thermistor that changes resistance over temperature. Should be simple......but with these cars nothing is simple......
Maybe I am just looking for a vendor that sells a quality replacement. I doubt that there are "tight" tolerances. Its just a thermistor that changes resistance over temperature. Should be simple......but with these cars nothing is simple......
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Willcox is where you want to go for a correct sending unit. Also, here's their page on how to test the gauge (which includes sender info): http://willcoxcorvette.com/instructi...Revised_R3.pdf
Melting Slicks
Joined: Jun 2011
Posts: 3,114
Likes: 598
I installed an new temperature sending unit on the freshly rebuilt engine. It looks like it might be off slightly on the cooler side. I took my original sending unit and measured 600K Ohms and then the new one in the car 50 Ohms. Something is not right.
Can someone measure the sending unit tip to block/gnd and get me a reading on a cool engine?
I am thinking I may have the wrong sending unit but physically its correct.
Can someone measure the sending unit tip to block/gnd and get me a reading on a cool engine?
I am thinking I may have the wrong sending unit but physically its correct.
lectric limited.com was the cloest and they claim their as +/-10% tolerance from unit to unit , which makes my gauge read cold. I have not tried any from Wilcox but so far they all suck.
If you find one that works let as all know.
I know my gauge is good as a tested using wilcox docs to measure accurate reading at the correct resistance.
Thanks....
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Guys.. None of the senders will read correct!!! I've posted this over and over and over...
You might get lucky and get a good one every now and then but it you do it's pot luck. There is no one making the sender with oil inside... and there is no one making them with the correct thermistor inside the sender.
I'm about 2 weeks away from having a fix for this issue... So hang in there, I'll make a post thread when completed. We are finished testing the product and while we've had some delays in this they were from my own accord. (too many irons in the fire). When finished, you'll be able to dial in your dash gauge no mater what sender you have.
Willcox
You might get lucky and get a good one every now and then but it you do it's pot luck. There is no one making the sender with oil inside... and there is no one making them with the correct thermistor inside the sender.
I'm about 2 weeks away from having a fix for this issue... So hang in there, I'll make a post thread when completed. We are finished testing the product and while we've had some delays in this they were from my own accord. (too many irons in the fire). When finished, you'll be able to dial in your dash gauge no mater what sender you have.
Willcox
Last edited by Willcox Corvette; Oct 3, 2014 at 10:10 PM.
Melting Slicks
Joined: Jun 2011
Posts: 3,114
Likes: 598
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Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Great Video Rob. My results in testing were not as good as yours. The issue that plagues that particular sender is that it is not capable of reading high enough. (or low enough in ohms output).
The sender worked fine until it hit around the 95 ohms mark... then it faltered. No matter how hot I got that sender it would not reach the higher end points of the scale. The lowest ohms output we could get was 95. (I did cut one apart and there was not any oil in it either). We tested three units...
This was three years ago too, so maybe something has changed but all three gave me the same result. Maybe I'll repeat my test to check it again.
As you can see from our input chart below 95 ohms would get you right below the 210 mark, which is okay if everything is working properly, but not good if you have a car that tends to run hot.
The sender worked fine until it hit around the 95 ohms mark... then it faltered. No matter how hot I got that sender it would not reach the higher end points of the scale. The lowest ohms output we could get was 95. (I did cut one apart and there was not any oil in it either). We tested three units...
This was three years ago too, so maybe something has changed but all three gave me the same result. Maybe I'll repeat my test to check it again.
As you can see from our input chart below 95 ohms would get you right below the 210 mark, which is okay if everything is working properly, but not good if you have a car that tends to run hot.
Last edited by Willcox Corvette; Oct 4, 2014 at 10:02 AM.
Le Mans Master
Joined: Jun 2006
Posts: 6,399
Likes: 1,226
From: Tampa Florida
I installed an new temperature sending unit on the freshly rebuilt engine. It looks like it might be off slightly on the cooler side. I took my original sending unit and measured 600K Ohms and then the new one in the car 50 Ohms. Something is not right.
Can someone measure the sending unit tip to block/gnd and get me a reading on a cool engine?
I am thinking I may have the wrong sending unit but physically its correct.
Can someone measure the sending unit tip to block/gnd and get me a reading on a cool engine?
I am thinking I may have the wrong sending unit but physically its correct.
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 751
Likes: 0
From: Chandler AZ
St. Jude Contributor
After looking around more and reading all of this I can see that I am not an isolated case here. Again this forum is great.
Wilcox if and when you find an alternate please PM me!
Thanks everyone for your inputs!
Wilcox if and when you find an alternate please PM me!
Thanks everyone for your inputs!
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
71ls5...
It's not a matter of finding, I have the issue solved. I have to finish testing the last prototype which will begin tomorrow. I kept making changes to the proto's and this delayed me a bit.
Edit.. I stopped what I was working on and started testing it again today.
Willcox
It's not a matter of finding, I have the issue solved. I have to finish testing the last prototype which will begin tomorrow.
I kept making changes to the proto's and this delayed me a bit. Edit.. I stopped what I was working on and started testing it again today.
Willcox
Last edited by Willcox Corvette; Oct 6, 2014 at 02:38 PM.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Today we completed the testing. I have one more pre-production meeting in two days and we will get this off and running. I will have solutions for 1968-1976 and the 1977-1982 dash units.
Basically what you'll have is a adjustable resistor for the back of the dash unit that will allow you to make a linear change in the gauge. This will allow you to match it to the sender to the dash unit.
Below is one of the older proto's...
Willcox
Basically what you'll have is a adjustable resistor for the back of the dash unit that will allow you to make a linear change in the gauge. This will allow you to match it to the sender to the dash unit.
Below is one of the older proto's...
Willcox
Last edited by Willcox Corvette; Oct 7, 2014 at 05:16 PM.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
We will have product in about three to four weeks. Once we receive the green boards, we'll begin production. Below is the last Proto. We changed the pot to a higher quality design which will increase production cost, but I felt it was worth the difference. I also changed the wire to stranded vs. solid because as most of you know it's more durable.
Below is the last proto picture, and below that I've posted the link. The links will be updated as soon as the product is on the shelf.
http://willcoxcorvette.com/advanced_...sistor&x=0&y=0
Below is the last proto picture, and below that I've posted the link. The links will be updated as soon as the product is on the shelf.
http://willcoxcorvette.com/advanced_...sistor&x=0&y=0