VX dry sump - low oil pressure

[Jon Stewart]

During a thrash last night i noticed the oil pressure guage fall right away and the pressure warning light flashed during sustained cornering. Once straightened up the pressure returns to normal. The car is a '91 Vauxhall with dry-sump and Pace anti-cav tank. Oil level is OK and i use Mobil 1 15-50.

Any advice/ideas greatly appreciated.

 

Thanks

Jon

 

Edited by - Jon Stewart on 2 May 2002 11:38:55

[ECR]

Sounds like low oil level

 

How are you checking the level ?

[Jon Stewart]

I was advised when i bought the car to check the oil level is just below the plate half way down the Pace tower. Does this sound right?

[ECR]

Not familiar with the Pace arrangement so I can't realy comment. If no one else jumps in with a suggestion I would increase oil level by small increments and see if problem dissapears. With the standard Caterham bellhousing tank I find that if I do inadvertently overfill I just blow it into the catch tank so it is semi self regulating. Far better too much oil than not enough.

[Jon Stewart]

Thanks for your response. I'll try that tonight. It's a bit tricky peering down the tank so i'll notch a depth gauge and try that way. Fingers crossed - i'm at the 'ring tomorrow -hopefully not in the Focus company steed!

[StewartG]

The Pace tank oil level should be about 1cm below the level of the baffle with the big holes in it when the engine is running. Any more oil means that this baffle cannot remove the air as the oil cascades over the rim of the holes. I don't think it's an oil level problem, after all the dry sump system is designed to stop oil surge and should make oil level uncritical. Try having a look at the pressure relief valve.

[ECR]

When I run low on oil in my VX dry sump I get oil pressure warning lights. This must be because the oil is so low in the tank that it uncovers the tank exit hole on cornering. Perhaps this is what is happening ?

 

By all means look at the prv but if that was the problem it wouldn't be cornering sensitive

[Peter Carmichael]

Oil *volume* is critical in a dry sump. The dry sump's tall external tank keeps the pickup immersed during cornering, but a small change in oil volume results in a large change in oil depth. When a dry sump oil tank runs dry, it is normally worse than when a wet sump surges. The design premise of the dry sump is that this should never occur.

 

Oil level should be checked immediately after shutdown having idled for a minute or so with hot oil. On some systems it is possible to measure with the engine running. The de-aeration baffle plate should be just above the tank oil level, as described. If you don't go through the rigmarole of running engine and shutdown etc, it will only make the tank appear more empty as you check it. Topping up will result in oil venting to the catch tank.

 

It sounds like you are checking the oil level correctly and a dry sump system is failing to perform its primary function if it cannot maintain pressure in such circumstances.

 

Have you checked the wiring connections to the oil pressure sender? Under cornering, the loom could be flexing and a dodgy connection might give you zero pressure readings.

[ECR]

Electrician I am not..

 

When the connection to my pressure sender oxidised I got a higher reading and was worried about blowing seals. Ruined a perfectly good opportunity to drive Le Luc.