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#1 oil pressure woes

Posted: Wed Dec 12, 2018 12:44 pm
by Ikebaddog
Decided to give the Series 3 a run into work this morning, however, pulling in for a fuel stop after a mile or so, the oil pressure light came on! the pressure gauge was reading 70-80-lbs, but the light stayed on, checked oil level, all fine, returned home and abandoned!!!!!
Any thoughts? what would you believe more, the gauge or the light???

#2 Re: oil pressure woes

Posted: Wed Dec 12, 2018 12:59 pm
by malcolm
Have you re-started it since coming home to see what happens? You could take the oil filler caps off with engine running to see if oil is pumping up as a clue.
I had error warnings (on my series 2) and it was just the sender.

#3 Re: oil pressure woes

Posted: Wed Dec 12, 2018 1:57 pm
by Ikebaddog
I will re-start it tonight, to see what happens.

#4 Re: oil pressure woes

Posted: Wed Dec 12, 2018 3:00 pm
by Paul Buckley
The light will also tell you that the handbrake is on.
I had a problem with the microswitch at the handbrake and the light would only go out when the handbrake was firmly pressed down.
Solved by adjusting the cable.
FWIW .....

Paul

#5 Re: oil pressure woes

Posted: Wed Dec 12, 2018 3:01 pm
by Paul Buckley
Sorry, had a brain fart!
I am talking about the brake fluid light ......
Duh!

#6 Re: oil pressure woes

Posted: Wed Dec 12, 2018 11:20 pm
by JJC
I'm guessing you have original electrical oil pressure sending unit. Might want to consider switching to a mechanical system. Spot on accurate, gauge looks the same, easy to install. Been discussed many times on this forum. Check it out. FYI....Series 3 V12 engines don't produce 70 to 80 lbs of oil pressure.....its the reason I'm guessing you have the old useless electrical unit. For example, if driving around 70mph, with the tach reading 3000rpm, for example, your pressure should 25 to 30 lbs. On a cold winter start, you might see close to 60lbs, but that drops way down once oil is warm.
JJ

#7 Re: oil pressure woes

Posted: Thu Dec 13, 2018 9:31 am
by Ikebaddog
Yeah, I understand that the original gauge is inaccurate, I just mentioned it as it was showing the same as it has always done, even when the light was on, I think a new gauge will be on the list of things to do. BTW tried it last night, light went out as soon as engine fired up!

#8 Re: oil pressure woes

Posted: Fri Dec 14, 2018 9:29 am
by Ikebaddog
Ok, looking at fitting a mechanical gauge, where do I tap off from on the oil supply?

#9 Re: oil pressure woes

Posted: Fri Dec 14, 2018 11:27 am
by Ole-xke1974
JJC wrote:
Wed Dec 12, 2018 11:20 pm
FYI....Series 3 V12 engines don't produce 70 to 80 lbs of oil pressure.....
Eh - mine does when cold.
Indicated on both the original and the mechanical oil pressure gauge. Both read the same within a couple of psi of the other.
I guess there are differences between engines and oil pumps.

#10 Re: oil pressure woes

Posted: Fri Dec 14, 2018 1:47 pm
by JJC
Perhaps when cold as I said, but 70 to 80 psi might have more to do with the thickness of the oil on a cold start-up. But once warm and on the road, oil pressure will never reach those levels. Rule of thumb for a normal street car , 10lbs of pressure for every 1000 rpm. Plus/minus a few lbs. Rev it up to 4000 rpm, gauge should show close to 40lbs, etc.

Happy motoring !

JJ

#11 Re: oil pressure woes

Posted: Fri Dec 14, 2018 1:51 pm
by JJC
John...as for tapping into the engine for oil pressure read, its the same spot as the electrical sending unit. When you get the mechanical set up from any Smiths dealer, it will all be easy to figure out. Very simple, easy install. And dead on accurate !

JJ

#12 Re: oil pressure woes

Posted: Tue Dec 18, 2018 3:01 pm
by Ikebaddog
Cheers JJ

#13 Re: oil pressure woes

Posted: Sun Dec 23, 2018 2:25 pm
by Bob.
Hi John

Yours being a 1971 car, if it has the original engine, will have the oil pressure switch and pressure sender located low down on the LH side of the block near the rear of the engine in a pretty inacessible place. The tapping is into the main oil gallery. This area is close to the exhaust and is susceptible to any oil leaks from above eg cam cover or cam oil feed.

From 1972 the tapping was moved from the main oil gallery on the side of the engine to a point part way along the cam oil feed pipework, with the switch and sensor located on top of the engine behind the throttle pedestal where, unlike the earlier set up, it would be very easy to add a tee for a mechanical gauge.

Hope this helps
1970 - 1971
Image
Image

Relocated during 1972
Image

#14 Re: oil pressure woes

Posted: Sun Dec 23, 2018 7:39 pm
by JJC
Spot on Bob: I did fail to mention...it was moved (thank goodness) I have a 73, so easy. Thanks foe mentioning that.. Merry Christmas

JJ

#15 Re: oil pressure woes

Posted: Mon Dec 24, 2018 10:35 am
by Ikebaddog
Fabulous, mine doesn't have the original engine, so hopefully will have the easier option!!!
On that note, my log book hasnt been updated with the new engine number ( engine fitted 12 years ago0, should I bother doing it?

#16 Re: oil pressure woes

Posted: Mon Dec 24, 2018 1:23 pm
by chrisfell
“On that note, my log book hasnt been updated with the new engine number ( engine fitted 12 years ago0, should I bother doing it?”
Yes. If it should ever get nicked, the log book will prove the number of the stolen engine.

#17 Re: oil pressure woes

Posted: Mon Dec 24, 2018 3:14 pm
by Series1 Stu
Ikebaddog wrote:
Mon Dec 24, 2018 10:35 am
On that note, my log book hasnt been updated with the new engine number ( engine fitted 12 years ago0, should I bother doing it?
Well, if you're at all bothered about having the documentation correct and legal then, yes, definitely.

Also, what Chris said.

Cheers!

#18 Re: oil pressure woes

Posted: Sun Dec 30, 2018 4:26 pm
by Ikebaddog
The reason I ask is, I bought it off a well known dealer that wasn’t bothered, and I phoned another well known dealer to ask if he would be concerned and he wasn’t, not in the slightest, anyway, it turns out I’ve got the oil pressure sender in Athens really awkward place..... how the hell do I get to the thing????

#19 Re: oil pressure woes

Posted: Sun Dec 30, 2018 5:39 pm
by mgcjag
Hi John.....thats interesting that they are not bothered about the engine number...The seller isnt worried becaus the car has now gone........the new dealer you called hasnt actually purchased it....would probably be a different story if you asked them to buy it.........did you check the number on xke data to be sure it wasnt stolen.....will be a whole different story if it was.....I would get the number checked out and the registration V5 changed.....this could have an impact on your insurance in the event of a claim.........I would never buy a vehicle where the V5 dosnt match.......Steve

#20 Re: oil pressure woes

Posted: Mon Dec 31, 2018 2:45 pm
by chris420sa
Hi All
Series 3 Oil Pressure etc
The "Operating, Maintenance and Service Handbook" states on page 2: ".. The minimum pressure at 3,000 rpm when hot should not be less than 2.8 kg/sq. cm (40 lb per sq.in)....After switching on, a period of approximately 20 seconds will elapse before the correct reading is obtained."
Hope that helps.
I'm sure there is not a linear relationship between rpm and oil pressure so I don't know what the pressure should be at, say, 5,000 rpm. The electric gauge on my 1972 Series 3 is calibrated from 0 to 80 psi and the sensor is mounted (thankfully) to the rear of the throttle capstan mounting.
Having taken a close look, it is not clear to me where one would route the tubing for a mechanical oil pressure gauge. Given that the dash panel hinges down, the tubing would have to have sufficient slack.If any member could please advise regarding the routing, that would be much appreciated. Also, is my gauge (0 to 80 psi) the original type and can one get a mechanical gauge with the same calibrations?
Look forward to your responses.
Happy New Year
Chris