Hi
I am having difficulty solving this problem and hopefully
someone out there wil have a solution.Have just installed a
rebuilt engine in my 3.4 mk2.
Oil pressure is 50 to 60psi when driving but at idle drops
to 15 to 20psi.
a mechanicle gauge is used directly from the main oil
gallery and I have fitted a stronger spring in the pressure
realease chamber with little or no change. The original oil
pump was used as it came up to specs when measured.
Any ideas please–
spitzstick
hobart, Australia
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
Nearly EVERY Automotive engine built measures it’s “Low Oil Pressure” at a
specific RPM Level… As is the case of the
XK120/MKVII engine, it is 40 to 45psi at 2000 RPM…
ALWAYS Read The Service Manual for specific and critical
details/specifications for YOUR vehicle/engine!
Charles #677556.----- Original Message -----
From: “spitzstick”
Hi
I am having difficulty solving this problem and hopefully
someone out there wil have a solution.Have just installed a
rebuilt engine in my 3.4 mk2.
Oil pressure is 50 to 60psi when driving but at idle drops
to 15 to 20psi.
a mechanicle gauge is used directly from the main oil
gallery and I have fitted a stronger spring in the pressure
realease chamber with little or no change. The original oil
pump was used as it came up to specs when measured.
Any ideas please
It is my opinion that you don't have an oil pressure problem.
The oil pressure specification for the XK engine is "The minimum
pressure at 3,000 RPM when hot should not be less than 40 lbs. per square
inch." It looks like you have that and more.
I have never found a Jaguar factory oil pressure specification for the XK
engine at idle and suspect that one may not exist.
My idea is for you to drive the car, enjoy it, and don’t worry about oil
pressure unless it fails to meet the Jaguar factory specification quoted
above.
BTW, that is for the 3.8L and 4.2L engines, but I believe it is the same
for your 3.4L engine,
Regards,
Paul M. Novak
1990 Series III V12 Vanden Plas
1990 XJ-S Classic Collection convertible
1987 XJ6 Vanden Plas
1984 XJ6 Vanden Plas
1969 E-Type FHC
1957 MK VIII Saloon
Ramona, CA
P.M.Novak7@gmail.com-----Original Message-----
From: owner-xk-engine@jag-lovers.org [mailto:owner-xk-engine@jag-lovers.org]
On Behalf Of spitzstick
Sent: Saturday, December 12, 2015 2:34 PM
To: xk-engine@jag-lovers.org
Subject: [xk-engine] low oil pressure
Hi
I am having difficulty solving this problem and hopefully someone out there
wil have a solution.Have just installed a rebuilt engine in my 3.4 mk2.
Oil pressure is 50 to 60psi when driving but at idle drops to 15 to 20psi.
a mechanicle gauge is used directly from the main oil gallery and I have
fitted a stronger spring in the pressure realease chamber with little or no
change. The original oil pump was used as it came up to specs when measured.
Any ideas please
Paul
The Low Oil Pressure spec for the XK120/MKVII, is exactly
as I quoted!! It is plainly detailed in the XK120/MKVII Service
Manual… Which is a Fantastic book… All one has to do is read it!
Charles #677556.----- Original Message -----
From: “Paul M. Novak”
Spitzstick,
It is my opinion that you don't have an oil pressure problem.
The oil pressure specification for the XK engine is "The minimum
pressure at 3,000 RPM when hot should not be less than 40 lbs. per square
inch." It looks like you have that and more.
I have never found a Jaguar factory oil pressure specification for the XK
engine at idle and suspect that one may not exist.
My idea is for you to drive the car, enjoy it, and don’t worry about oil
pressure unless it fails to meet the Jaguar factory specification quoted
above.
BTW, that is for the 3.8L and 4.2L engines, but I believe it is the same
for your 3.4L engine,
In reply to a message from cb@xktx.org sent Sat 12 Dec 2015:
Thanks for all the input.
I have always replaced the oil pump on previous rebuilds
with a high flow one. This time I didn’t.
With a highflow pump you get a much higher pressure at idle
No more worries then thanks
Roger–
spitzstick
hobart, Australia
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –
Up to recently my Mark 2, 3.4 has has good (50psi) oil pressure at anything above 1500 rpm- confirmed with wet line gauge. Now I find when I start from cold it goes up to near 60 psi - as it always did, but after 20-30 seconds slowly drops to around 20 psi, then recovers, does it again then is OK.
Engine runs well, not noisy, very low oil use and no smoke.
Any ideas why it has suddenly started doing this?
EFIT: when I put in a new one, the old one looked perfectly serviceable: I could not see anything on the sealing surface that would even be sensible, with a mic: same spring, same ~160,000 mile oil pump, it went from ~5 psi, hot/idle, to ~25 psi, hot/idle.