Added a aftermarket gauge package to the Wildcat. To keep the factory W/T sender functioning I placed the new sender in the extra port on the rear of the L head. It works but reads 200-220* Dont think that the engine is over heating and the idiot HOT light has not come on. My question is will the location on the rear of the head read that much hotter than the one nearest the thermostat.
Yes, it will be. That is NOT coolant temp but rather cylinder head temp. Used to turn on the HOT light as a last warning before meltdown.
Brad, on the Nailhead it looks as if the right and left heads are interchangeable as with the later style V8s I own. If I was to take that head and swap it to the right side that same port would hold the factory temp sender. Both have coolant flowing through them. Only thing I can think of is its simply hotter back on the rear of the block than closer to the radiator where its reading coolant temp fresh from the rad. There was nothing but a threaded plug in that hole and it looked old enough to be factory
ALL NailHeads have that plug on the rear of the left head. Buick used that spot for temp. readings from '53-'59 when they used an actual temp. gauge in the car.
Verify the temperature reading with an infrared heat gun. The back of the head will be COOLER than than the front: flow is from the lower radiator thru the block, up the rear of the head, across the head then out to the radiator.
Hey Steve. That is where I have my temp gauge, I use the front (original source) for my EFI coolant temp. I am about 6-10 degrees hotter reading from the back of the head for the dash gauge compared to the EFI temp reading as taken from the ECU(the original sender location). Be aware that since it is at the rear of the head, it will read much hotter after shutdown and restart than reading from the front, appearing to be very hot, but only for a few seconds as the coolant starts flowing again. First few times it was a bit alarming, until I realized it was because the latent heat and time to react to the coolant flow on start up when warm. (like filling fuel or stopping at the store) I also added a "T" at the front for the idiot light, since I liked having a "highest temp" reading from the rear of one head, and the "actual" coolant at the front from the EFI ECU. And did not want to snake the temp gauge slinky all around the engine from the front. (While I tend to gaze gauges every few seconds as a lifelong habit, I also like the "Master Caution Light Panel" as an attention getter.) Hope that helps.
This is a really small and inexpensive gauge probably made in the 70's so I have doubts on how accurate it is. The OP and volts seem to be right on. I wanted to use something like this to keep it out of sight but visible when I want / need to see it. Close the ash tray and its completely out of sight. I'll do detail and trim work whenever its time for the int to be refreshed.
