How much oil pressure should a 63, 3.8 engine have when hot at idle? I have 40 plus at 3500 but only 10-12 at idle when hot. New engine, high volume oil pump. Any ideas?
Thanks,
Peter

 

I'm not an E-type authority.

The only spec I've seen for the XK 6-cylinder engine is for the later 4.2 variants ---- 40 psi at 3000 rpm hot

Lacking any spec the rule of thumb for engines in general is 10 psi per 1000 rpm

Yours sounds Ok to me

Others will chime in

Cheers
DD

 

Yeah, looks about right although the tickover pressure seems a bit low. What oil are you using ? The oil pressure sender can also get a bit lazy.

 

note a lot of oil gauges are merely fancy pointers, especially the replacement ones. If you want a proper reading to confirm your worries, hook up a proper test gauge to the oil pressure point. ebay for 30 Euro/dollar/pounds and you can use it on your gearbox and other cars too as a bonus !

 

Used straight gauge. Don't trust electric but it fits car. On third sender now. Who makes a good one? Engine has great idle pressure for 45 min then drops to 10. Always good at any speed other than idle. Wierd.
Guess that's how it runs. Changed the oil filter assembly again. No benefit.
Starts good, tho.
Thanks to all.
Want to buy an almost perfect car? Less than 400 miles on total resto. Eat off any part of it.
Peter

 

Not really.

It's common for o/p to drop quite a bit at idle, double so when warm, on any engine.

The V12s often drop to less than 10 at idle.


Yeah, probably "just the way it is". I think you might be trying to fix something that isn't broken

Cheers
DD

 

Thank you all for the fresh air. It has eased my mind. I've waited 7 years for the damn thing and really want to drive it before I die. Drive and enjoy it, that is.
My sincerest thanks to you all.
Peter

 

Only other thing to ask is what oil are you using ? Sometimes changing to an oil that was current for the engine when it was in production can get a better pressure.

 

Think it's Castrol 20/50 but might've Joe Gibbs break in oil. Been through so much so frequently. I'll have to check my records.
Thanks

 

What is your idle RPM? I know the manuals call for a very low rpm, (usually around 700)...But I have always run my rpms on British cars at between 850 and 900...They always seem to like it better, especially starting out in 1st gear....
Some folks will say it's not necessary, but it helps to keep the hot idle pressure up.
There's a theory out there , that says that it's not the pressure that really counts, but the volume of oil getting to the critical parts...Good oil flow can sometimes show lower pressures...Anyway, that's my "take" on it.
Edward