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MG MGB Technical - Engine oil pressure



Hi everyone,

I have just replaced the engine oil in my '67 Mk1 BGT with the oil and renewable filter. I find that the engine oil pressure stays up at 50 - 60 psi, even at engine idle speeds and with a warm engine. Like the rest of the car, the engine is in excellent condition, having been properly restored. Before the oil change, the gauges were reporting typical idle and drive engine oil pressures.

Is this simply a case of fresh oil holding it viscosity better or is there a concern here. I did made the oil service carefully.

Thanking in advance.

Brian McIlvenna
Brian McIlvenna

Brian. This is not uncommon with a good quality rebuild. You will see a slight loss of pressure at idle as the engine wears over the years. This has never caused me a problem and I do not worry about it. Les
Les Bengtson

Brian,
An interesting question and one I have been toying with asking for some time, although, like Les, I have not been particularly worried by constant higher pressure given my motor runs well.
I bought my 69 MK11 last April and have done one oil/filter change since then - it is due for another now. I also noticed the same effect following that change. i have wondered whether I managed to alter the position/setting of the by-pass valve when carefully and thoroughly wiping out the filter base. My cah has the original filter base and housing - yes, I know, but it is part of the fun I get from owning the car so I don't mind the fiddling at all.
My engine is the original with 119,000 miles on the clock which would be genuine from the full service records I have back to 1971. The head was reconditioned in 1985 because of a shot head gasket so it runs really well all things considered, certainly too well to be concerned with thinking about a rebuild at this stage.
I will be interested to see whether there is any change in the guage behaviour with the next change, which I should do in a few days. Keep in touch if you like and I'll let you know.
Regards
Roger
Roger

Roger,

interested in your posting. Please do let me know how you get on after the oil change. I left out a few words in my original message, intending to say that I had replaced the old oil with the correct oil grade (SAI 20w50), bought from a British classic car component supplier.

The interesting observation would be how the pressure, particularly the one associated with the engine idle speed, changes with the kilometers after each oil change. I don't do alot of driving, typically 5.500km per year, so it will take me some time to ascertain this parameter.

Many thanks, speak to you later
Brian McIlvenna
Brian McIlvenna

Brian,
Will do.
Roger
Roger

Ihave had my Gt for 22 years, I used to be obsessed with the oil pressure reading.The oil pressure can be adjusted to release pressure at a highre level by adding/removing shimms to the release spring/valve.There was a artical in the MG Owners mag a few years ago.
regards
Ray

This thread was discussed between 22/01/2002 and 28/01/2002

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