Disco 1 3.5 no oil pressure

Hi
I've got this disco 1 3.5 efi which I have recently done an engine replacement. As the working engine I put in had been sitting for a while I did the vaseline trick in the oil pump as didnt have oil pressure initially, which worked. However when I started it up i found I'd forgotten to put a new gasket in the oil pump and it was leaking so after fitting a gasket in oil pump and putting a vaseline equivalent into the pump I started it and ran it for about a minute but I havnt got any oil pressure anymore. Should I try repacking it with vaseline more tightly? I would appreciate advice for what to do now, thanks in advance

Re pack the pump and prime it with a drill before firing her off.

Is the drill priming essential? Or can you risk starting it and letting the engine do it? I think it's a right faff taking the distributor all out and getting a tool and everthing

Did you fill, as much as u can without it running out, the filter with engine oil before fitting, I did once and the green oil light stayed on for around 5 seconds maybe a few more, anyway now with oil in the filter before replacing the filter it is back to normal... off as soon as the engine starts.

Yep I filled the oil filter up as much as I could before putting it back on.. when the vaseline does work how long does it take for the pump to start sucking the oil out the sump?

davebuckley3000 said:

Yep I filled the oil filter up as much as I could before putting it back on.. when the vaseline does work how long does it take for the pump to start sucking the oil out the sump?

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Don’t know sorry, but it’s an old trick and mentioned in the early RR 3.5 days as the thing to do when fitting a brand new pump, I have a look in my old manuals if there’s any thing more stated other than filling the pump with Vaseline.

You could also try removing the ignition stuff, rotor arm for instance, or distributor cap, so it won't start and then just cranking it on the starter until the oil pressure light goes out.
This is an old trick on all sorts of engines. Can't harm it.
And if you fear this is too much for the batt and starter take at least some of the plugs, if not all of them, out.

Stanleysteamer said:

You could also try removing the ignition stuff, rotor arm for instance, or distributor cap, so it won't start and then just cranking it on the starter until the oil pressure light goes out.
This is an old trick on all sorts of engines. Can't harm it.
And if you fear this is too much for the batt and starter take at least some of the plugs, if not all of them, out.

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Thanks this is a good idea, will give it a go. I've already had it idling for a couple of minutes without pressure so very reluctant to start again before I get pressure. Tvm

Here are possibly some of the other reasons and methods.
http://www.locostbuilders.co.uk/viewthread.php?tid=62634
Best of luck

davebuckley3000 said:

Thanks this is a good idea, will give it a go. I've already had it idling for a couple of minutes without pressure so very reluctant to start again before I get pressure. Tvm

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How do you know that there isn’t any oil pressure? please don’t say that the green light doesn’t go out

Relief valve stuck? I'd want to put a real, known working pressure gauge on
Failing that, take a rocker cover off and see if you can see oil squirting

kermit_rr said:

Relief valve stuck? I'd want to put a real, known working pressure gauge on
Failing that, take a rocker cover off and see if you can see oil squirting

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I’d expect with the oil pressure switch removed there would be a mess if the pump is working as it should

davebuckley3000 said:

Yep I filled the oil filter up as much as I could before putting it back on.. when the vaseline does work how long does it take for the pump to start sucking the oil out the sump?

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When I rebuilt my 3.9, I did the vaseline trick and I'd say within a few seconds of firing up (no more than 10 secs) the oil pressure light went out.