Oil pressure switch info -

[Cerb420James]

I recently had a faulty oil pressure switch with my cerbera. Naturally I ordered one from TVR parts but it was temporarily misplaced so I ordered another from racetech - both very helpful companies.

I removed my oil pressure switch - was the original with the TVR part number.

Now where it gets interesting.

Parts suppliers are supplying a 1/2” unf threaded switch.

This does go in but doesn’t feel like a quality fit-

So I compared it to the original - the threads are ever so slightly different.

My original sensor has a 1/4 BSP thread - it would appear this is almost non existent to buy a switch with this thread, I could do what I was told but another TVR specialist “just fit the switch, it will be fine” looking around I have seen the switches have a relatively high failure rate and people suffer with leaks.

I didn’t want to run that risk.

So I looked in various supplier catalogues and found a switch that operates correctly and will illuminate at 0.8 bar (11.7 psi) with enough meat on it to turn it down and tap a 1/4 bsp thread on to.

Job done, screws in, torqued up. Job done.

Looking into it - basically not all engines are like this. TVR tapped The same threads for the oil pressure gauge and oil pressure switch fitting. Makes life easy but I the 1/4bsp switches became obsolete so they then changed to (I’m guessing) 1/2” unf.

For reference, my engine is a 4.2 build number 0572 - TVR had the engine in 2003 for something or another ( later sump installed at this time also ) There was word that they retapped the oil pressure switch hole when engines were back but perhaps not or if the pressure switch wasn’t broken - don’t fix it kind of thing - probably.

Anyway if anyone has troubles or would like a 1/4 BSP switch I bought a few to have turned down just in case!

[ukkid35]

Really interesting to hear your feedback

I have just fitted another of these with no issues at all

Brand Kerr Nelson
Weight 0.036 kg
Thread Size 1/2" UNF
Number of Poles 1 -pin connector
Spanner Size 22
Technical Information Number Circuit N.C.
Housing Colour Black
Function Oil Pressure Switch
Extra Description Kerr Nelson
Net weight [kg] 0.028 kg

https://www.ebay.co.uk/itm/233400409008

[Cerb420James]

Like I said some were 1/2” unf and the difference is 1 thread per inch which with the oil switch would be almost unnoticeable. You just get a more positive feel with the 1/4 bsp

[Mr Cerbera]

Brill post, informative and helpful