oil pressure

[gary123]

Started my latest project and oil light wouldn't go out, so got a new one (thanks Julie). Still don't go out.
There is no continuity between terminal and earth so Im ruling out a short and Ive used a test light with pos to battery and neg to terminal, that doesn't go out either.
What to try next? Drop oil and check gauze pick up ? Could the filter be an issue ?

Please dont make me take the engine out 

[K2-K6]

If you think it's flow on first establishing the pressure after rebuild, then take filter off completely, turn it over until you see the oil coming out of that supply to filter housing, then refit filter and try it for pressure then.

[gary123]

If you think it's flow on first establishing the pressure after rebuild, then take filter off completely, turn it over until you see the oil coming out of that supply to filter housing, then refit filter and try it for pressure then.

Cheers Ill give it a go.

[K2-K6]

To add.... with a freshly built engine it can air lock the system out from pump head and just stop the pump from getting supply through initially, opening the system stops that happening.

Its got to go through there firstly, so you might as well check it there. Once the pump head and ongoing delivery pipe to filter has oil fully in there it'll pump effectively.

[Nurse Julie]

Have you got any tell tale signs of oil at the top end Gary or is the oil not getting that far (regardless of if the light goes out or not?)

[Oddjob]

You could try removing the pressure switch, turning over the motor and see if the oil comes out of the hole.

The 500/550 doesn't suffer with air lock like the 750 so I doubt it's that. However doing the above should clear that if it is the case.

Does holding the wire going to the pressure switch against the engine make the light go out? If so, faulty switch.

[gary123]

Have you got any tell tale signs of oil at the top end Gary or is the oil not getting that far (regardless of if the light goes out or not?)

No, pretty dry up there.

[gary123]

Does holding the wire going to the pressure switch against the engine make the light go out? If so, faulty switch

No, that brings the light on. I think its supposed to, it just bypasses the switch which breaks the circuit when up to pressure.

[gary123]

I have removed the filter and noticed that its very deep in the housing. Its very tight on the bolt and not bouncing on the spring so may not have seated correctly.
Do you think that could be the problem ?
Tomorrow Ill drop the sump just to eliminate that.

[K2-K6]

I have removed the filter and noticed that its very deep in the housing. Its very tight on the bolt and not bouncing on the spring so may not have seated correctly.
Do you think that could be the problem ?
Tomorrow Ill drop the sump just to eliminate that.

Shouldn't make a difference to pressure, even if it wasn't in there at all. The housing floods first, then the oil is squeezed through filter material to get to rest of engine. 

[Bryanj]

In all the time i have been doing them i have had 1 and only 1 that wouldnt self prime, i removed the pressure switch and filled pump through the hole then refitted switch.
Least messy way of checking oil flow is to remove cam cover end caps the the bolts holding the steel brackets down, oil should come out of the bolt holes

[gary123]

In all the time i have been doing them i have had 1 and only 1 that wouldnt self prime, i removed the pressure switch and filled pump through the hole then refitted switch.
Least messy way of checking oil flow is to remove cam cover end caps the the bolts holding the steel brackets down, oil should come out of the bolt holes

Ill have a look at that in the morning.

[K2-K6]

If it doesn't come through there to the oil filter housing, then by default it won't arrive at the head. It's the only route it can take.  There's no other path.

It's essentially free to check at the filter location to see if it gets there, that's irrespective of what we think any problem may be.

Checking at camshaft is ultimately pointless IF there's no oil at present at the filter.  Fine to check head if it's getting to filter though.

[McCabe-Thiele (Ted)]

Might be worth nipping the pump off to check the drive pin is in place, if you take the end plate off  you can rotate the pump with the kick start and see if it's rotating - also see if there is oil there.

It might be possible the plate seal is pulling in air instead of oil from the sump.

[gary123]

Well thanks for all you replies, all of which I have done.
Oil filter off, pump off, sump off replaced all and refilled pump through the pressure switch hole. Spin it up and, kerching all is good.
Cant really say what it was but priming pump seems most likely.