Low Oil pressure.

PostPost by: englishmaninwales » Tue Mar 16, 2021 4:40 pm

vstibbard wrote:You could remove end cover of the oil pump and smear the gears and body with vaseline, assembly lube or grease, this creates a vacuum tfor the initial lift of oil up from the sump.


Tried this yesterday. After years of having difficulty in getting pre start oil pressure after an oil change, this works well.
Thank you.
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1994 Caterham 7
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PostPost by: billwill » Tue Aug 03, 2021 1:03 pm

I eventually felt a bit fitter (after my short stay in hospital last year) so finally got around to dealing with this low oil pressure problem. Following up suggestions in this topic, I had tried spinning the engine on the starter with plugs out without getting any oil pressure reading.

I wanted to avoid changing the oil pump if possible so the problem seemed to be either a clogged filter or a stuck-open pressure relief valve.

I would replace the oil filter in any case doing an oil change so that was a non-problem anyway,, and I felt that a thin oil would help clear any other clogging. I checked the various discussions here and for other cars on the use of flushing oil and noted that in one of the workshop manual even LOTUS themselves did not recommended use of flushing oil, but they qualified that statement with the comment "due to the difficulty of removing all the flushing oil". So I decided that I would use a flushing oil, but follow that up with a filling of what I call "sacrificial oil". This would be a normal engine oil but as low a price as practical but still compatible with the engine. I would only run it for a short period, say 100 miles, without any high stress) and then do a second oil change to the real (expensive) engine oil (Miller Sport). So I chose Halfords' Classic 20W50 as sacrificial oil. Weird stuff as it is dyed green!.

Anyway, I got my Elan S3 onto wheel ramps within the confines of my garage by jacking up the front suspension with two jacks, (oddly getting it onto the wheel ramps was easier than getting it down later).

Then I was able to crawl underneath (somewhat dusty after two static years) and drain the old oil and remove the oil filter. Funny how one does those up hand tight, but you never seem to be able to remove it again without a fabric loop wrench or similar tool. then I filled the first replacement oil filter (Halfords HOF203) with flushing oil (CARLUBE) and fitted it to the existing pump. Then I put the appropriate quantity (3.5 litres) of the flushing oil in through the main oil filler hole in the cam cover.

It was rather late then so I left it till the next day, perhaps not the wisest approach. But I put the battery on charge & waited till the next day. Checking the internet etc instructions there was no mention of a delay it was expected that the engine should be started and idled for 10 to 15 minutes then the flushing oil drained out.

Anyway the next day I spun the engine on the starter with plugs out and was delighted to see a small rise in oil pressure on the gauge, so all looked good. But would I be able to start it with 2-year old fuel?

Anyway, full choke, some dabs on the accelerator and she coughed & spluttered into life. It took a while to settle down, but eventually was idling fairly well. And HEY PRESTO the oil pressure was up to 40 psi, (appx 1400RPM) dropping back to about 30psi at lower idling speeds (800RPM). So I ran it on idle for about 15 mins and then stopped the engine and drained out the flushing oil.

Then I trotted over to Halfords to get the sacrificial oil and another oil filer for the sacrificial oil run, only to discover that they don't do their own brand anymore and they have no idea and no way of finding which Crosland oil filter is compatible with it and their online look-ups seem to have purged the classic cars. I just got funny looks when I said Lotus Twin-Cam or Ford Cortina (I couldn't remember which other cars had used the same canister). Disgruntled I returned home with just the green oil, realising that I would have to use the Wix oil filter that I had obtained from Sue Miller for the sacrificial period and get yet another one from her for the real engine oil later.

Well I removed & discarded the filter I had fitted the day before as it now contained flushing oil and flushed (?) gunge etc, Then I filled the WIX filter with green oil and fitted that & then (remembering to put the oil drain plug back in :D ) put the appropriate amount of the green oil in through the normal filler hole in the cam cover.

I started her engine again and was pleased to observe that it seemed to be working properly except possibly a sort of hissing sound that I didn't remember from before, the oil pressure was behaving properly as expected, so I idled it for about a quarter hour etc then shut it down after a successful day. Hooray.

Next day, I slightly worried about that noise, I warmed her up and then removed to top cover to check that the oil was getting to both inlet and outlet cams (it was OK) and the timing chain. It was but the chain seems a little bit too slack so I adjusted the tensioner to make it a bit tighter and put the cover back on.

Then I moved my other car out of the way and took my Elan out onto my forecourt to give it a good wash-down with hot soapy water and a cold water hosepipe. I didn't actually take her out for a run yet, but at least I know she works and is clean and shiny again. {I also swept all the dust out of the garage :? }.

Anyway all I need to do now, is check the tyre pressures and take her out to get some more fuels. and order another oil filter so that I can do yet another oil change in the near future to get rid of the sacrificial oil.
Bill Williams

36/6725 S3 Coupe OGU108E Yellow over Black.
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