Winged Sump

[jonclancy]

OK, out it comes again for another clean and a shim with a couple of washers. Maybe I'll try polishing the spare plunger and spring and refit that as Plan B.

Probably be next week, now. But I'll see if I can grab a half hour in the garage tomorrow - work PM.

I can't see how my new ball can have got stuck, mind you. Unless there is some junk working it's way through. Ah well, it's not as if the weather is any good for driving.

[jonclancy]

Replacement plunger out of my spare engine was polished, lubed and reinstalled with the spare MG spring.

All looked very good. 65psi under running. Around 40psi idling.

Even under hard acceleration to max revs, the psi never exceeded 70.

And there was neglible change under hard braking.

But the plunger appears to have stuck again. Under high revs it's 65psi, but drops off at idle. Tried topping up the oil, and made no change. This all happened after around 4 miles of motoring and the engine was hot.

I have a feeling that there is either crap floating around, or the pressure regulator bore has become pitted or scored.

Either way, I'm out of ideas now. I can have another look down the bore with my mirror, but whether I can see the cause of the sticking plungers and ball is another matter.

As always, any pointers most gratefully received. I'm off to work soon, but will have a think about things on the way.

Plus side is the performance of the sump. Shall I arrange for a run of CNC-folded casettes for early new year???

[Westfield 129]

It sounds as though it is working fine. Idle pressure should be very low, increasing with RPM until it tops out at about 60 psi.

What RPM does the pressure top out?

[jonclancy]

Tops out at about 3500 revs.

Idle pressure is barely off the stops. It's definitely bleeding off pressure back to the sump.

[Westfield 129]

40 psi~65 psi is normal. Spring pressure seems to be OK.

Check your oil pressure line for a bubble. You might bleed it at the gauge and see if that helps.

I doubt that the plunger is still sticking. Especially if you get normal pressure on start up.

[jonclancy]

That is a very good point, Jan. I'll look into that. Lost my last post, but will prob look at the oil for any clues too. Will get some more stunt oil and some filters and give it a flush.

It's a bit of a pain this, but any engineering problem solving practise is good experience..

[jonclancy]

Just got back and straight into the garage. The plunger is, yet again, stuck. I removed it and it has witness marks on it. Mirror inspection shows marring of the plunger bore.

So, it's back to try the ball-bearing again. I have some fresh stunt-oil and filters coming and am currently draining the sump. BTW, it drains well. I've just jacked up the back and placed a block under the rear nearside wheel to get the last of the oil out. There was some crap on the mag-plug, so hopefully a fresh load of oil and new filter will sort that side of things out. It's the plunger bore that concerns me, but if the ball-bearing can be made to behave (I'm thinking with the stronger spring), then we could be on the way to sorting this one out.

[adamwilkinson]

so long as you always have pressure I wouldn't worry too much about fluctuating pressure, you have good pressure under load which is the main thing. if your oil pressure warning light doesn't come on then you have enough pressure at idle not to cause issues.

the only way we solved the drop in pressure at idle (once warm) was going drysump - its now too high but that's just fine tuning of the relief valve spring to bring that down.

if you are really concerned about the oil, fit a temperature gauge - this will tell you if the oil is getting too hot and thinning out too much.

Get rid of the plunger!!!

[jonclancy]

Plunger is got rid of!!

I'll refit the ball balve and see how we do. I've emptied the oil and await my fresh supplies.

I was having a chat with someone this morning about the ball-bearing, and apparantly the seat is a press-fit. I didn't know that. If the ball doesn't work, then the pressure relief valve bore can be honed smooth again. That's an engine out job as all the paste will need to be cleaned out. Anyway, I'll see how I do - update after Xmas, unless my oil arrives today or tomorrow.

[biggles]

Holy thread resurrection batman!

What happened in the end with your winged sump Jon? I was reading the "stevenh" build thread on the WSCC site and he had an, IIRC, Swiftune winged sump fitted, triggered my jet lag addled brain into a fuzzy memory from a couple of years back...