ETB Instruments and 1/8" Temperature sender

[LLantrisant]

as i understand TVR fitted the big-threaded temperature sender (5/8") with an adapter inside the intake manifold (1/8"??)as there wasnst a sender with suitable thread available? is that correct?

below my gauges, 1993, chimaera. i hope those are ETB?



yesterday, when browsing through ETB´s homepage i recognized that they are offering temperature senders with 1/8", 5/8" and M10x1

https://www.etbinstruments.com/index.php?route=pro...


so here we would have the solution for getting rid of the adaptor and bring the sensor straight into the water flow?



before somebody is answering " do the rover modification":

early (pre-serpentine) engines do NOT have the rover sensor installed, just the ECU sensor and beisdes of it a casted unthreaded boss.

[LLantrisant]

update:

the thread inside intake manifold seems 5/8" not 1/8"? can anybody confirm this?

do i understand right that the original adapter ( https://www.racetechdirect.co.uk/car-parts/cooling... ) has both sides a 5/8" thread?

so why did TVR not screw-in the sender directly into manifold? or do i make a thinking-mistake here?

[Steve_D]

LLantrisant said:

..........so why did TVR not screw-in the sender directly into manifold? ................

Not investigated but, some senders have quite a long sensor 'Nose'. is it possible the hole in the water jacket is not deep enough to take that 'nose'.
That would also answer why the factory adaptor is so long.

Steve

[FoxTVR430]

Here is the sensor and sensor housing from my 1993 Chimaera.
The screw threads look different to me, but maybe it's the angle of the photo.
Also the sensor does not protrude from the housing.

[LLantrisant]

the thread inside manifold should be 5/8"...according to what i have found on rover v8 engines rover p6, SD1, Discovery etc.

sensors for those cars have a similar length of nose

ETB is listing a 5/8" sensor....so in my theory this sensor should fit diretcly into manifold, that would consecutively means it also sits fully covered by water sinde the cooling circuit, hence the readings on the gauge should be more precise and less delayed.

so why TVR used this extender?

[Dougal9887]

The serpentine manifold is tapped 1/4" NPT to take a thermostat bypass pipe. TVR used this tapping with a 3/8" NPTF x 1/4" NPTM adapter for the 3/8" NPTM sensor. They could have just drilled and tapped the existing threaded hole to 3/8" but for whatever reason chose to use an adapter; I have done this re-tapping exercise but it doesn't appear to make a discernible difference to the gauge reading, I daresay it may have a quicker response time.

The pre serpentine manifold did indeed have a 3/8" NPT tapping for the sensor, however that was on the opposite side of the thermostat to the tapping TVR used.

Dougal.

Edited by Dougal9887 on Monday 24th June 22:46

[LLantrisant]

confused now even more....

i´m talking about pre-serentine, by the way.

the manifold is a standard rover part--correct?

so why this differncies in the threads? 5/8 in SD1, 1/4 and 3/4 at TVR....

did the rover-cars (like discovery etc) also had the (gauge) temperature sender fitted in that location or did rover use a blanking plug in that area?