hi all, trying to install oil pressure gauge in Mk1 8 valve, but it seems the t-piece needs to be 21mm. the largest i can find is 18mm. has anyone done this already and can advise please? regards Richard

what are you trying to tee into exactly??
I would look to just install a pressure sender in one of the unused holes near the oil filter - then you just need to send a wire from it to your gauge....

hello Blue, thanks for the reply. I was planning to put the t-piece between the original sender and the take-off point by the filter. didn't realise I could use the other holes. Many thanks, i'll give it a try. regards Richard

There is 2 blanked holes down there. Should be able to use one ?

Hello Blu, all installed and registering (90 psi at 2000 revs seems a bit high). It was an 18mm thread after all, not sure why i needed a 21mm spanner originally. Anyway, many thanks your advice.

can't say i have measured the pressure on one before myself.. 90psi does seem very high, whats that?? a bit over 6 bar

I would expect it to be around 3 bar rather than 6. I know the FIRE engines have really low oil pressure on idle - I know a lad with a pressure gauge but i never paid much attention to the actual numbers but i remember it goes way lower than you'd expect on idle. I don't suppose the actual figure matters too much so - it should stay pretty steady at anything other than idle when it will drop. So it is showing you that you have pressure and thats all it really needs to do - can't be right though 6 bar.