lower

If its blowing out oil then there is cylinder compression leaking into the oil system somewhere.

That could be via the head gasket, piston rings, the pistons themselves or a cracked block.

If its not the head gasket, i'd be inclined to think you've got a cracked piston or broken rings.

MarkB

What he said.

The pressure from the cylinders is blowing oil back out of the system from what you've said. First check I'd do is cylinder compression (as you don't need to take the engine apart) to find out which cylinder is losing compression into the crankcase. From there it's a case of checking rings etc. until you find the cause.

Did you have the engine checked before dry sumping?

dreamer

Hiya - it's always been dry sumped (I've had it 2 years and it was done long before that).

I see what you're saying about the oil blowing out - dry sumps always blow a bit of oil out into the catch tank, and certainly if you overfill them they just pump it out. Mine has always put a bit out (lots do) but this did about 3/4 litre in a morning which is unusual to say the least (would normally be a couple of inches).

All this does sound quite expensive, but Mark that's useful to know - I'm taking it to the engine place tomorrow (because the engines are race sealed it needs to go to a particular person) so it's useful to know there are less expensive (less labour intensive) places to start checking!

dreamer

that's also interesting - it put some creamy stuff into the catch tank a few weeks ago on a very very cold day, then on Saturday it spat out clean oil for a bit, and finally when it bit the bullet it spat out a little bit of this milky type stuff again. Indicate an intermittent problem? Seal going?

lower

That fact it spat out milky stuff once and then not for a while probably indicates its not head gasket.

Milky oil can also be aerated oil as well oil mixed with water. So if rate of combustion leakage was going up it might be this that is causing the final spurt of milky stuff.

My father in law and i share an old ford sierra estate as a 'tip' car and this had a cracked piston. Symptoms were very similar though it never actually expired. Thankfully he was a mechanic and owned a couple of garages before he retired so he was able to fix it for just the cost of a new piston and a head gasket.

MarkB

Which could point to the scavenge pump.

If it's damaged internally and is cavitating, it could be the cause of the fluctuating oil pressures which in turn could lead to premature failure of a component due to starvation somewhere. Especially if Jo continued to drive the car hard after first noticing the symptoms.

Jo, is the scavenge pump driven by a toothed belf off the crank? If it's failing it might be causing the drag on the crankshaft, which you'd see as the car seeming like it's losing power.

dreamer

Interesting stuff guys I'm learning a lot

I didn't drive it hard, no - came in first of all and checked it over, then went out for about 1.5 laps before stopping - at least 3/4 -> 1 lap were spent coaxing it - certainly not driving it hard.

Scavenger pump could be a thought.

dreamer

Mark just seen your question - errrrrr not sure.. what's a belf??

MarkB

A typo.

I meant belt.

dreamer

Damn thought I'd learnt a new word then

Yes there is a belt but I don't think it's tooth driven?