oil pressure (lack of)

[vonjono]

I'm stumped and would welcome any advice.
I have a SV minor special - running well with v strong oil pressure.
The copper pipe that goes from the sump strainer to the oil pump was leaking from an end flange - I broke it during removal so I had a new one made up and replaced it taking the opportunity to change the oil too.
Start the engine - no oil pressure on the gauge (but engine sounds OK)
Taken off the pressure gauge pipe and oil just dribbles out looking very frothy (I thought it should spray out).
Checked my replacement pipe and it's not blocked and there is no leakage, strainer OK, oil pump looks OK ?!?

Please help before I lose any more hair,

Many Thanks !

[Simon]

Hello,

Try taking off the pipe to the pressure gauge squirting engine oil into the oil pump with a pump type oil can. About 50cc should be enough. If the oil pressure is then OK but drops again you probably have an air leak in your new pipe.

Good Luck

[Ian Grace]

I agree - if the system was good before the pipe swap, the problem might be that the pump is not primed. You can also over-fill the sump and run the engine very briefly just to get pressure up and then drain down to the max mark on the stick.

The other issue might be that the new pipe unions are not completely tight and the pump is sucking in air. They have to be VERY airtight on the inlet side to the pump to get good oil pressure, and this might explain the frothiness.

Good luck and let us know how you get on.

Ian

[Sam Christie]

I had a friend who had a problem like this caused by using silicone sealant as a gasket but it oozed on tightening and blocked a connection. It caused some consternation till it was discovered.

[Highlander]

I am sure you just need to prime the pump. Every time I change the oil on my sv minor I have the same problem - i.e. no oil pressure. Prime the pump and the problem is solved. Highlander.

[vonjono]

Thanks to all,

I'll give it another go following your kind advices !

and will let you know the result.

Kind Regards,

Jon

[Mike Stubbings]

Hi All, I have also heard of blockages due to silicone. Caused by small pieces breaking of from inside and forming blockages in system. I still use it on occasions but try to make sure none squeezes through leaving excess on the inside on the joint. Mike

[vonjono]

Hi again all,

I have found the problem - the union from the pipe to the oil pump side leaks (established when I overfilled the sump as per prior advice) thus dragging air in.

The 'nut' is quite badly butchered hence my inability to tighten it properly.

Any idea what I need to ask for when I look to source a replacement - and where is good to approach for this type of component - I guess this won't be a bespoke fitting but something perhaps more widely available.


Many thanks & regards

[Toby]

I think Paul Beck or Vintage supplies may be able to help, not sure of thread size, would probably be BSP?

[Trevor Wilkinson]

When I had a similar problem I sourced unions and fittings plus some small bore copper pipe from a local plumbers suppliers.