Pressure relief ball

[Steve kay]

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6 psi at idle when warmed up would lead to the beginnings of slight concern at blocked jets, engines have shown 10/12 when fired up then about 2 when ticking over after getting the oil hot. The mag engine has shown 2/3 when cold, down to the pin almost immediately. The dawn chorus this morning had the birds singing loudly in Welsh. At one point I thought I heard them calling out, dipstick, dipstick. I only have one magneto engine dipstick so nothing to compare it with. Any comments?

[Reckless Rat]

Just trying to think outside the box... are the oil jets standard, or has someone opened them out to a larger diameter?

[Chris KC]

Steve, others who can't see your engine and don't know or recall what you have already done could help you better if you listed up methodically what you have already checked in every part of the system. It's easier to spot something missing or incorrect in a list than to pull fresh ideas out of the ether (which will end up going around in circles). This thread already runs to 7 pages & I for one have forgotten what was said on page 1 by the time I get to page 4...

[Stuart Giles]

[quote="Steve kay" pid='93827' dateline='1684218668']

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No obvious problems with the pump, that is the pump with the mirror smooth cover. Relief ball seat not chipped. Plugs removed and access to galleries checked, no evidence of being blocked. So now what?
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As you have the motor more or less in bits, you could partially assemble it -oil pump in, sump on, oil in sump and then drive the cam with an electric drill and see what is happening WRT oil delivery (or not) at the jets. An engine I worked on a while ago had the oil jets drilled out, there was lots of oil being delivered by them, but no pressure at tickover and not much at running RPM once the oil was hot.

[Steve kay]

Indeed, the very next step, to see what the pump delivers and where. But that’s for tomorrow morning says an old and achy Seven strangler.

[Timbo]

pressure test the oil pump OFF the motor.
If it has been over-bored and the machinist has touched the base of the pump the oil will flow past the bottom of the vanes.
From David Grear.

[Steve kay]

pressure test the oil pump OFF the motor.
If it has been over-bored and the machinist has touched the base of the pump the oil will flow past the bottom of the vanes.
From David Grear.

David

The pump was tested on the bench yesterday, it propelled, indeed projected, oil more vigorously than expected! The flattened and polished pump bottom plate made a guest appearance in episode 76 some weeks ago, or was it years ago.

Further advise will be required in due course. As almost everything else has been checked and/or changed,  I will get new and thus correctly shaped jets. Hints on how to remove the old ones and install new ones?  And lowering the drive gear down onto the oil pump drive shaft. Does this just require long and gentle slowly offering up the gear trying to find the slot for the key, before tapping it down the shaft, or is there some cunning way of aligning it. Advise so far is to find someone else with small and nimble fingers who makes clocks and watches and works as a neurosurgeon during the day.

[Steve kay]

   

And now, ladies and gentlemen, we bring you oil pressure!  I cannot give sufficient thanks to the noble Sevenists who inhabit the forum, and share their knowledge and experience. Can I think of a single reason for the previous lack of pressure, and the current abundance thereof? No. The process has just been a thorough detail re-assembly, buying model steam boiler tube cleaning brushes for the oil galleries, polishing the oil pump base plate to mirror smoothness, buy an enlarged oil pump body from Tony Leslie, new jets from David Cochrane, and apologies to anyone missed off the list which means something will have been posted from Jamie.