[v12-engine] Oil pressure normal reading?

Took my V12 out for a drive yesterday. AFter pegging at 60+
during warm up, it settled down to under 20 lbs and stayed there,
irrespective of revving, load, etc. Is that normal? What should
I expect? If not normal, what would cause that?

Thanks in advance.–
Bill Gutierrez, '61 OTS '73 OTS
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The 5.3L is notorious for low idle oil pressure. The gauges are not always accurate. For example, I just replaced the transmitter with a brand new one and managed to even find a “new old stock” gauge. At start up of cold engine it shows about 75 and settles down to about 25 when warmed up. OTOH, I drove for many years with less than 50 at startup and about 15 warm. The thing is, there are several different transmitters and several different gauges and if they aren’t match you can get nearly anything.

The general opinion seems to be these engines do not have oil pressure problems.

Ed Sowell
'76 XJ-S coupe, red
http://www.efsowell.us

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In reply to a message from Ed Sowell sent Wed 31 Aug 2016:

Yup…its a low oil presure engine. Once you are fully warmed
up, you should show 10 lbs of pressure for every 1000 rpm. Good
rule of thumb. I hope you are using a mechanical sending unit and
gauge from Smiths. The only sure way to go.

John–
The original message included these comments:

The general opinion seems to be these engines do not have oil pressure problems.


wallstman1
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In reply to a message from wallstman1 sent Wed 31 Aug 2016:

The gauge and sender are the same for the last 30+ years
(and perhaps original). As noted in my original post, the
concern I have is that the gauge does not respond at all to
engine revs. It settled down to perhaps 15 and just stayed
there whether I was at idle (600 rpm) or revving freely
(5500 rpm). That is what I found abnormal. Sounds like it
is…so what could be causing it.–
The original message included these comments:

Yup…its a low oil presure engine. Once you are fully warmed
up, you should show 10 lbs of pressure for every 1000 rpm. Good
rule of thumb. I hope you are using a mechanical sending unit and
gauge from Smiths. The only sure way to go.
John


Bill Gutierrez, '61 OTS '73 OTS
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In reply to a message from Lundabo sent Wed 31 Aug 2016:

Buy a master test gauge and remove all doubt, or get your
local tech to take a reading. Dead easy from the fitting
up top on a V12. I think your car uses an instrument
voltage regulator that could be causing the instrument to
read low (shorting the sender wire briefly should peg the
gauge) but a mechanical reading is the best short term
reassurance. If a wet gauge reads low you need to dig
deeper.

Pete–
The original message included these comments:

there whether I was at idle (600 rpm) or revving freely
(5500 rpm). That is what I found abnormal. Sounds like it
is…so what could be causing it.


66 ‘UberLynx’ D, 70 FHC, 79 S2 XJ12L, 97 XJ6L
Gaithersburg, Maryland, United States
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Hi Pete,

I’m not sure about the '73 but on the '72 E-Type the oil pressure sender is
not easily accessible at all, but is rather thoroughly hidden between the
engine block and the left-rear exhaust manifold. You can’t see it and you
certainly can’t touch it without removing a lot of other things. I had to
replace my sender and so I also connected a mechanical gauge while I was in
there, so I know of what I speak. Also, the electrical oil pressure gauge
is not connected through the IVR on any Jaguar that I am aware of. Other
than that your advice is good: First determine if there really is a problem
before you try to solve it.

Mike Eck
New Jersey, USA

'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2

In reply to a message from Lundabo sent Wed 31 Aug 2016:

Buy a master test gauge and remove all doubt, or get your
local tech to take a reading. Dead easy from the fitting
up top on a V12. I think your car uses an instrument
voltage regulator that could be causing the instrument to
read low (shorting the sender wire briefly should peg the
gauge) but a mechanical reading is the best short term
reassurance. If a wet gauge reads low you need to dig
deeper.

Pete

The original message included these comments:

there whether I was at idle (600 rpm) or revving freely
(5500 rpm). That is what I found abnormal. Sounds like it
is…so what could be causing it.


66 ‘UberLynx’ D, 70 FHC, 79 S2 XJ12L, 97 XJ6L
Gaithersburg, Maryland, United States
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In reply to a message from wallstman1 sent Wed 31 Aug 2016:

As noted in my original post, the
concern I have is that the gauge does not respond at all to
engine revs. It settled down to perhaps 15 and just stayed
there whether I was at idle (600 rpm) or revving freely
(5500 rpm). That is what I found abnormal.

I picked up on that. I agree, abnormal – but the nature of this oil system is
pretty much it works or it doesn’t. I suppose there COULD be something
flaky going on inside the filter head that’s just dumping the oil back into the
sump rather than pushing it out to the galleys, but that’s not terribly likely.

Far more likely there’s something wrong in your gauge. There are LOTS of
things that can go wrong in that instrument cluster, including bad grounds or
whatnot that might cause the oil gauge to read lower as the temp gauge
reads higher, or something similarly silly.

Meanwhile, what’s the engine sound like? An engine that is truly starved for
oil usually starts making noise such as clacky tappets.

– Kirbert

Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !On 31 Aug 2016 at 18:29, Lundabo wrote:

I’m not sure about the '73 but on the '72 E-Type the oil pressure
sender is not easily accessible at all, but is rather thoroughly
hidden between the engine block and the left-rear exhaust manifold.

Ugh. Is it leaking oil? If not, just abandon it in place and install a new sender
somewhere easier to get to. I think there are threaded plugs in the main
galley all the way down the left side of the block. Unscrew one of them,
screw in a braided hose, route the braided hose to someplace on the firewall
where you can conveniently mount a new sender.

If it’s leaking oil, you’re gonna need to replace it – but I’d replace it with one of
those plugs. Oil pressure senders are NOT reliable enough devices to be
installed in inaccessible locations.

– Kirbert

Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !On 31 Aug 2016 at 23:16, Mike Eck wrote:

In reply to a message from Lundabo sent Wed 31 Aug 2016:

Thank you for all the responses. I guess I’m going to have
to dig in and figure out where the sender is. The saga is
never ending. ;(–
Bill Gutierrez, '61 OTS '73 OTS
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In reply to a message from Mike Eck sent Wed 31 Aug 2016:

Dunno Mike - only owned a 73 E, but every E and sedan V12
I can remember had a multi-way fitting up top for sender &
switch & cam feeds. For my master gauge suggestion I was
just referring to tapping into the oil system via that
route using any port on the fitting at the top rear in the
Vee?

Admittedly I’ve been spoiled by mostly UK / RoW engines
with no emmissiona tubing and gulp valve in the way…

Pete–
The original message included these comments:

not easily accessible at all, but is rather thoroughly hidden between the
engine block and the left-rear exhaust manifold. You can’t see it and you
certainly can’t touch it without removing a lot of other things. I had to
replace my sender and so I also connected a mechanical gauge while I was in
there, so I know of what I speak. Also, the electrical oil pressure gauge


66 ‘UberLynx’ D, 70 FHC, 79 S2 XJ12L, 97 XJ6L
Gaithersburg, Maryland, United States
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Dunno Mike - only owned a 73 E, but every E and sedan V12
I can remember had a multi-way fitting up top for sender &
switch & cam feeds.

OK, that raises a question: XJ-S, XJ12, or E-type, the Jaguar V12 is gonna
need oil feeds to the tappet blocks. If the oil pressure sender on the E-type is
hidden underneath a manifold, does that mean there is no pedestal on top
where these oil feeds come together? If so, how are the tappet blocks fed on
the E-type? Might it be a good idea to retrofit the later pedestal to the
E-type?

Also worth noting that reportedly TWR felt too much oil went to those tappets
and installed a pressure regulator in the line to limit flow.

– Kirbert

Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !On 3 Sep 2016 at 17:32, PeterCrespin wrote:

In reply to a message from Kirbert sent Sat 3 Sep 2016:

I was talking to George Camp about something else and he
confirmed early V12s had a sender low down. The E-type
pparts book cites a multiway union up top - part C37763 -
with switch, sender and cam feeds off it. That’s the only
version I’ve seen on an E but I haven’t worked on many or
looked hard so Mike is right too, as George confirmed.

The blankng plate on the block has two numbers. The first
is C35165 which is probably the early threaded sender
version and C37963 (only one digit off C37763) is
presumably the later version to match the later multi-way
fitting?–
66 ‘UberLynx’ D, 70 FHC, 79 S2 XJ12L, 97 XJ6L
Gaithersburg, Maryland, United States
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Early V12 E types had the sender in the blanking plate in the side of the block. Later ones and XJ12s had the sender unit in the pedestal to which the cam feed pipe was attached with a banjo bolt. The oil warning light switch was fitted into the cam feed pipe.This is the easiest place to fit a wet line gauge. You can fit this type on an early E type but not a five minute job if engine is in situ!!!

Thanks! I haven’t had a chance to dig into the situation, but will look at this first to see what I have and whether I can fit a wet line gauge there.