Zero oil pressure

[EEED]

Hi All,

During a very short trip yesterday I noticed that the pressure gauge was showing zero. I was only about two hundred meters from home when I noticed, so very carefully drove the car back and parked up. I subsequently re-started the engine a couple of hours later but still no pressure. Last weekend I had drained the sump to rectify some slight damage on the drain plug which appeared to be the source of a leak. I refilled the oil, topped it up with some new oil and allowed it to stand for several days before staring it.

The pressure gauge was new three years ago. The engine was rebuilt last year and has been showing good pressure. It seems too much of a coincidence for the problem to be unrelated to draining the sump. but I can't think why it should result in zero pressure. has anyone experienced this problem before? Any help greatly appreciated.

Paul

[robertverhey]

With zero oil pressure it should be rattling like a tin can full of bolts. First thing I'd do is to disconnect the oil gauge either at block or gauge and crank motor with coil disconnected or spark plugs out. See if oil flows out while cranking. If so I'd then be trying another gauge. If not then time to check oil pump, and then on to the sump.....bearings etc

[john.p.clegg]

Paul

Is it electric (could be your Voltage regulator or just a wire come off) or is it capillary?

John

[promotor]

As already mentioned it is a good idea to see if the engine is actually pumping oil out of the oil gauge hole.

Also, check to see if the oil pressure relief valve in the oil pump is stuck open - if it is that'll put your pressure right down.

[billwill]

You can easily destroy the engine if you run it with a real zero pressure.

[Olympicblue]

Hello,

A trick if you do not have oil pressure,
Remove the lateral plate, put some oil in the gear of pump, replace the plate.
It will priming the pump.

Of course you have to be sure that the pump is OK, but if the engine stayed for a long time without running, it could be that

Damien

[EEED]

Hi,

Thanks to all who replied to my post. Responding to the points raised in no particular order:

The engine didn't sound distressed in any way.

I checked the pressure without the plugs in as suggested. Still zero at the gauge. Replaced the gauge with an old one that worked before I took it off the car a couple of years ago. Still zero.

Disconnected the capillary from the block - nothing spurts out. Oh dear.

Anyway, I have decided to take it to my local garage (or rather have it taken) so a transporter is coming tomorrow to collect it. I hope it's no more than the pump or a stuck relief valve but I'm not confident, I'll report back after it's been checked over.

Thanks again

Paul

[richardcox_lotus]

Just adding (hijacking?) this thread as I took my Sprint out today & the pressure at hot idle was the lowest I've ever seen it - about 10psi - its usually about 16. It was rattling a bit when I arrived home. Never read zero though, & pressure did increase when revved.

The idle speed is currently a bit low at 600rpm & the cam cover gasket is not in the best of shape, although according to the dipstick I haven't lost much oil. Before I start thinking about oil pump issues would these 2 factors be sufficient to drop the pressure 5psi or so ??

(New gaskets ordered by the way). It wasn't a great drive today actually, as a couple of times I couldn't get 2nd gear either.

Look fantastic when washed though !!

[EEED]

Hi All,

An update and a question.

The oil pump is OK and there's no debris in the sump. The investigation has moved to the pick-up assembly and possible loss of suction. It's the early type pick-up with the bolt-in connection (not the later push in type) so there are, I understand after checking several suppliers, no remanufactured replacements.

Can anyone tell me if there should be a washer - perhaps copper - between the pick-up assembly and the engine block?

Paul

[rgh0]

There were two types of the early pickup.

One type had a short compression nut and a bush that fitted in the end of the tube that sealed between the tube and block

The other type had a longer compression nut and the flared end on the tube sealed directly on the block.

The block was machined the same in both cases.

If you use the first type without the end bush fitting then it will not seal before the compression nut bottoms out and you can get no suction. If you use the second type with the bushing from the first type then the nut does not engage properly and you cant really fit the lock washer and the nut can work loose and you loose suction.

There is also supposed to be a lock washer under the compression nut with tabs that are bent over to lock the nut to the block.

I found all this out after pulling a pickup and an end bush fitting from a bin of spares before I knew about the difference and struggling to fit the lock washer properly as the nut did not go in fully. The difference in length is only about 6 mm so its not obvious by just looking

cheers
Rohan

[EEED]

Hi,

Belated thanks to all who replied.

The problem was solved after the replacement of the oil pump and the replacement of the oil pick-up. It's a bit of a mystery; there wasn't anything obviously wrong with either of the old components. The car hasn't had a great deal of use since due to business commitments but so far, so good.

Paul

[CBUEB1771]

For some reason I missed this topic when it first started. By any chance had you recently replaced the oil filter shortly before noticing the zero oil pressure condition? Did you replace the filter again when installing the new oil pump? Many years ago I installed what turned out to be a bad oil filter. All was fine for the first 20 or 30 miles and then I had zero oil pressure. I replaced the oil filter a second time and normal oil pressure returned immediately.

[EEED]

Russ,

Thanks for posting.Yes, I had just changed the oil and replaced the filter. No-one I contacted thought that the filter could (potentially) be the problem although I'm sure I explained that I had just changed the oil and filter.

At least if anyone has a similar problem and tries a search on the Forums they should find this - it could be a money-saver.

Paul

[oldchieft]

I recall one post at least about this.

lotus-twincam-f39/loss-oil-pressure-t30804.html#p206519

Jon te Chieft

[ericbushby]

I also had zero oil pressure about 60 miles after changing the filter. The pressure gradually fell during about 2 miles of running.
After exhaustive investigation and finding no faults another filter was fitted. All was well then and it has been fine ever since. It is now due for another oil and filter change and I will be very careful where I buy the filter.
Eric in Burnley
1967 Series 3 DHC