Pressure relief ball

[Chris KC]

While there take look at the upper surface of the pump cover plate (which is visible in the above photo, lower side towards us).

These are sometimes badly worn, if so you can lap it on some lightly oiled emery on a FLAT surface (e.g. surface plate) until clean and bright.

[Steve kay]

   

   

   

Things to remember to carefully check in future, the condition of the oil pump cover. On removal it looked pretty poor, so much time spent on piece of glass with grinding pastes to make it as smooth as a mirror.  Result, oh dear (a paraphrase of my actual response). The Ruby must now surrender its gauge, known to be working, for tomorrow's latest action. Otherwise, what else is there to be checked/corrected? Might a jet be oversize, dribbling rather than squirting and not giving back pressure off the oil gallery? Yesterday found myself in a very early and original Chummy. The owner, a smooth and gentle driver and very polite chap, told me that in his view, oil pressure gauges are for hairdressers. Real men have a dubious little button on the dash, which gave quite enough information thank you. .

[Chris KC]

Well that looks better anyway.

Steve, I'm sorry but I'm losing track of what you have checked, it may be helpful to summarise?

- PRV ball & spring replaced
- PRV ball seated
- Oil pump vanes (condition) - I guess you checked them visually.
- Oil pump vanes orientation - chamfer at the top?
- Oil pump vane springs - good
- Oil pump base plate - now nice and flat
(n.b. Seven Workshop sell both vanes and springs new, you might consider replacing them)
- Gasket between pump body and crankcase, but not between base plate and pump body?

And you still have only ~1psi COLD?

OK I'm clutching at straws now but:
- is the oil pump drive gear done up tight? (I've never heard of one slipping but...)
- is there a blockage in one of the oil galleries?
- has one of the little oil drilling end blanking plugs (1/8" BSP I think) popped out into the sump? (There are two of these inside the crankcase in line with the pump crosswise)
- is the wrong rear camshaft bush fitted? (Diameter changed over time - big bush on small shaft = big internal leak)
- I presume there isn't a huge puddle of oil under the car?
- Have you tried a different oil pressure gauge?
- Is the oil pressure gauge pipe blocked or kinked? (I once had a little flake of Hermetite block the outlet to the gauge pipe)
- What grade of oil are you using?
- Was the car running with OK oil pressure previously? If yes what have you done to the engine since?

["Slack Alice" Simon]

That is better than my car, engine up to temperature, idling.

Revving to get it into top from third maybe gets it up to 6 psi, trundling along at 35, maybe 3 to 4.

[Chris KC]

That is better than my car, engine up to temperature, idling.

Revving to get it into top from third maybe gets it up to 6 psi, trundling along at 35, maybe 3 to 4.

If I understood correctly Simon that's the cold pressure at start-up, if so definitely not good.

[Steve kay]

Continuing responses are much appreciated, if sometimes only to confirm the true mystery we have. Engine newly assembled from scrupulously cleaned parts. Oil pump parts as fully discussed above. Pressure gauges swapped, oil flow checked, gallery clear. Oil pump drive assembled as they have been before, so whilst avoiding complacency no immediate concerns. Two items mentioned by Chris that will require inspection tomorrow, and they are the blanking plugs. Not found on the gauze, but no recollection of having double checked their presence, that's just a sump off job. The other question is the gasket on top of the oil pump, described in Woodrow as joint washer. To get to the retaining nut on top of the oil pump drive shaft might access be possible by lifting the block with pistons at half stroke? On the Chummy, taking off the starter motor will allow access to the two back nuts, whereas on the Ruby splitting head from block is an engine out job. No I am not going to drop in a three cylinder Kubota to allow 76mpg!  Further reports in due course.

[Alan]

Steve, I wouldn’t even think twice. Take the engine out. It takes less than an hour and it will make everything else so much easier.

[Ian Williams]

I just had a thought about your continual low oil pressure from cold. If you have accidently put the wrong rear cam shaft bearing into the crankcase you can experience this phenonium. The early rear bearings are slightly smaller external diameter so if fitted into a later engine oil leaks between bearing and crankcase.

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PS I see Chris has just mentioned the same thing.

["Slack Alice" Simon]

Very odd.

Missing blanking plugs would do it, I suppose.

Missing gasket at top of pump - probably not.

What is the flow like from the connector, if you undo the oil gauge to crankcase joint?

It is always the thing I forget when installing an engine, the size of the puddle after a few seconds first engine run is very impressive.

If that happens, you know there is plenty of oil flowing round the engine.

[Howard Wright]

Very odd.

Missing blanking plugs would do it, I suppose.

Missing gasket at top of pump - probably not.

What is the flow like from the connector, if you undo the oil gauge to crankcase joint?

It is always the thing I forget when installing an engine, the size of the puddle after a few seconds first engine run is very impressive.

If that happens, you know there is plenty of oil flowing round the engine.

Hi Simon

I did almost exactly this recently and still have the iridescent sheen on the drive to prove it.  However in my case I simply hadn’t tightened the joint and the gauge showed a healthy pressure despite oil pouring out of the engine!

Hi Steve

My money is on the oil gauge or oil gauge pipe being faulty or blocked.  If you can find another gauge simply connect it to the engine without installing it in the dash.  I have a cheap eBay gauge and length of pipe that I use to test things with.  If I can find it you are welcome to borrow it. If the Chummy pipe run is the same as the RK the pipe bends sharply to go through the bulkhead and it is easy to kink it.

Good luck

Howard