No Oil Presure

[philward]

Just doing pre start up checks - electrical system and got round to the oil presure, of which there is none!
This is what I've checked so far:-
- Filled with approx 3 litres of oil (10mm past top mark)
- Checked continuity on new (genuine Honda) oil pressure switch (showing ground at contact) - does not change when kicking (and a quick spin on motor - I did cover all surfaces with Graphagen!)
- Re-stripped and checked pump tolerences - new pump kit fitted from Julie on build. (seal dowels in place with seals)
- Pump rotor punch marks aligned
- When oil pump out, oil seeps from crankcase at pump entry point (bearing) - not at either crankcase gallery point (that go to pump)
- No oil at filter housing
- With pump installed but cover off, pump is turning
- On kicking over with oil pressure switch removed and my finger over hole, there is no pressure I can feel
I originally filled the pump on original assemble with vaseline to prime pump (as I have done with my 750 builds) but removed it when told it shouldn't be needed on wet sump SOHC.
Any suggestion much appreciated (does it just need priming?)
Phil
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[royhall]

Never had a 500, but on others I usually remove the pressure sender and fill the oil galleries with an oil can. Sometimes takes a surprising amount. However, never owning one I stand to be corrected.

[philward]

I did Ken

[K2-K6]

Take the oil filter off to see if it's pumping there,  that's the first in line from the pump.

It may assist the pump with that open as you create a airlock-ish with graphogen sealing the oil run out routes.

If it gets there it'll usually be ok if you put the filter back on and crank it.

[royhall]

It will just be priming Phil. It can't get it's first pull when nothing but air is in there. The prime though the sender has never failed for me.

Sent from my Nexus 7 using Tapatalk

[philward]

I'll do as per the suggestions tomorrow - can't think of anything else except priming - pump within tolerance and is turning - all oil ways totally clear (really went to town on this area).
At what point does pump pick up oil? From sump via oil screen I guess? Should the oil level be high enough to physically reach the pump gallery level or is this where there could be the air lock?

[Nurse Julie]

Is 3L oil enough in a completely dry engine, I thought is was 3.5 or 3.7. I could be getting me engine volumes muddled up though.

[philward]

Is 3L oil enough in a completely dry engine, I thought is was 3.5 or 3.7. I could be getting me engine volumes muddled up though.

Honda shop manual says 3 litre 'Capacity' Julie

[Bryanj]

Dont lots and never had to prime a 500 BUT it can take  5 mins or more on starter for oil light to go out.
Remove plugs and spin it over then see

[philward]

Just as a matter of interest Phil but how fast were the rotors spinning when you had the cover off, I’m wondering if the drive pin is located on the inner rotor, it’s been a long time since I had an oil pump open on a 500 but seem to recall the inner rotor is driven by a pin through the oil pump shaft, maybe it fell out when assembling and you didn’t spot it. The rotors moving could just be friction on the shaft

Sorry Ken. missed your post - pin defo in and hence rotor spinning fine

[K2-K6]

The oil pump is just not very good at pumping air, if the onward system is resistant (the graphogen is an effective seal in the bearings) it just can't pull the oil into the pump head sufficiently.
By cranking with filter removed it prevents it building air pressure, then once you see the oil arrive into the filter chamber the pump head and pipe both side of it will be purged such that it'll pump the oil easily.
It will usually take only about 30 sec further to fill the galleries with the filter back on.

[philward]

The oil pump is just not very good at pumping air, if the onward system is resistant (the graphogen is an effective seal in the bearings) it just can't pull the oil into the pump head sufficiently.
By cranking with filter removed it prevents it building air pressure, then once you see the oil arrive into the filter chamber the pump head and pipe both side of it will be purged such that it'll pump the oil easily.
It will usually take only about 30 sec further to fill the galleries with the filter back on.

I'll get on it in the morning - thanks for all your help

[philward]

All sorted - primed pump and took oil filter off until oil appeared - then filter back on, spun motor for 10 seconds and light out. Panic over.
Thanks all

[royhall]

Nice one. It's always a priming problem.

[eight0]

Good info. I'll be needing it very soon!