I recently bought a 1961 MK2 jaguar with a 3.4 litre engine. One thing I noticed was that the oil pressure seemed very high.at 3000rpm [Off the guage]
I have never liked the electric guage fitted to this model as it can be very inaccurate. I subsequently replace it with a wet [Direct pressure] guage.
Pressure is now 20psi at tickover and 45psi at 2500 to 3000rpm on a warm engine after a long run. With it being a wet guage I know this is correct.
Is this about right? The car has only covered 39000 miles which can be fully guaranteed with documentation. [I am the second owner since new] The car has never been restored and still runs on its original engine which has never been out. Saying that the car is fifty years old so maybe? the pressure may be a little below what it should be

 

The pressure values you describe are about right or even better than right, for a hot engine "after a long run", especially if you are running on modern oils, and with no oil cooler. The original Jaguar Mark 2 gauge of 1959 was changed to max reading of 60 psi rather than 100 psi in 1962 according to Paul Skilleter in his book on Jaguar saloons, (published by Haynes April 1980), so that the normal pressure of around 40 ps i showed up well on the gauge. So I dont think you have anything to worry about.

 

Thanks for the reply to my oil pressure question.The car runs on Millars 20/50 oil. Not sure if this is classed as a modern oil? But if not, what modern oils are suitable, as I find it difficult locally to buy millars and usually have to buy it by mail order.

 

Sounds OK to me. <shrug>

The 4.2/XK engine spec is 40 psi at 3000 rpm warm. You're in that ballpark.

Not that mine is the final word but I can't see why the earlier 3.4 would require more or less oil pressure than the 4.2.

Cheers
DD

 

As the XK engine came out in 1948 it saw every oil development for the next 35 years !! 20/50 was not around in 1948 nor for many years afterwards, it was all straight SAE30 or 40 most people used, and the XK engine usually needed a pint adding too, at every 2nd fuel stop !

I would think you would have no trouble using the oil grade recommended for the last of the XK engines in the Series 3 XJ6, which was, (if my memory serves me correctly), 15W40. As the engine left production in 1986, I suppose even this is not a modern oil ! This may, however, be more freely available than the Miller 20/50.

 

Thanks to all for there replies,15/40 will certainly be easier to purchase locally so I will try this next oil change.