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MG TD TF 1500 - Other oil pressure questions

Someone suggested putting another oil meter on the oil line to check pressure, and that seems smart, considering this is a 60 year old meter that wasn't working at all till this year when I disassembled and cleaned and reassembled it, but...
My oil pressure seems pretty steady at 20 psi at 1000rpm and 40-45 at 2000rpm. When let idle, she drops to 10 psi, but that's a pretty low idle.
1) What should our idle rpm be?
2) any simple tricks to checking actual rpm vs the Jaeger gauge, which I have absolutely no expectations is any more accurate that the oil pressure meter?
3) in installing a cheap modern oil meter for accuracy, what size fittings are needed? Is this a British fitting for the oil line?
Thanks in advance,
Geoffrey M Baker

geoffrey, i believe conventional wisdom on the board is 10 psi per 1000rpm. (i.e. at 4000 rpm 40psi.)
tough right out of over haul because you have yet to establish a history, but oil pressure is more about sudden change or gradual change over a long period giving a good idea of internal wear.
hot engine at low idle, 20psi is not unusual.
as a frame of reference, low oil pressure idiot lights on modern, high revving engines illuminate at 2-5 psi. regards, tom
tm peterson

Also, of course, if this is an earlyish car, the take off for the oil pressure gauge may be at the head end of the oil feed pipe rather than at the block end. That can give a reading which is 15 or so pounds lower than the later cars. Same delivery pressure, but since there is less restriction of the oil flow at the head, the pressure reading can be quite different.
Lew Palmer

Sorry, I didn't read the other thread first where the issue of the take off point for the gauge is well covered.
Lew Palmer

Well, I thought I would start with a fresh benchmark; a complete oil change. Once that was done, base pressure at idle is now over 20 and at 2000 rpm it's almost 50. I'll check it again in a day or so, but that's good news; like many of our cars, my TD sits so much of the time that even with few miles on the oil, it's still been 4 years since an oil change and I imagine that makes for old, congealed oil clogging lines and affecting readings.
I switched to Mobil 1 synthetic 10/30W after reading up on the issues in the archives. Here in Tucson I definitely need a lighter weight oil.
Geoffrey M Baker

geoffery, four years of little use should not make oil congeal..but you should change you oil more frequently as the combustion by products will produce acidic by-produces that will etch smooth bearing surfaces. regards, tom
tm peterson

How should you change the oil on a car that isn't being driven or run?
Geoffrey M Baker

I meant...how often should you change the oil?
Geoffrey M Baker

Geoffrey , as a rule of the thumb : once a year.
Assuming you don't drive the car in the winter.

cheers,

Gerard
Gerard Hengeveld

My oil pressure meter line connects to the head. It connects through a banjo that runs down to the block.
Does anyone have a picture of the opposite setup?
Geoffrey M Baker

This thread was discussed between 19/05/2014 and 22/05/2014

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.