Sudden Scroll Failure?

[parkview094]

I've had my Morris for the last 12 years and in that time it's been pretty reliable but has always left a very minor 'calling card' when parked up for some time. The leak has never bothered me that much and I've never had to top up the oil between annual services. We've been going on the annual MoT trip to France so it's racked up some good mileage and never had an issue with long motorway journeys.

Ahead of this years MoT, the clutch was slipping so took it to a garage around 90 minutes away for a pre-trip inspection and new clutch.

On the return journey, I noticed the oil pressure gauge (MM) was reading much lower than normal (not getting much above 20).
Having gotten home, I checked the oil to find the dipstick was dry. I assumed the garage just forgot to top up the oil again as it took 4 litres to get it back to the max.

Over the coming weeks, I drove the car normally without much concern and all was good ahead of our trip to France. We set off and 90 minutes later to a strong smell of burning discovered once again, all the oil appeared to have been lost. Again, over 4 litres was needed to top it back up.

I've checked the breathers are all clear.
There's no significant blowing from the filler cap and no oil in the air filter.
Compression is down on all 4 cylinders but roughly equal at between 105-115
There no smoke at all when cold and I'm pretty confident the oil's not being burned off.
There's no visible oil leak in the engine bay. I've cleaned it and thoroughly inspected after a run. The oil filter canister is dry on the outside and it's not coming out the dip stick

The car appears to be leaking significantly more now from underneath than it has done historically.
We've replaced the sump gasket and cork seals, but now there seems to be a steady drip from the split pin after a decent run.

The only culprit left I can think of is the scroll? But I'm surprised that it appears to have failed so suddenly and dramatically? Anything else to check before ordering a new engine?

[svenedin]

Hello Mark!

Those compressions are significantly reduced suggesting a very worn engine. The engine breathing can only cope with so much blow-by and eventually it is so much that the crankcase pressure rises and the engine starts to leak very badly especially from the scroll. I think rather than sudden wear you have just reached a "tipping point". My engine before it was rebuilt did not leak much oil at idle but the oil consumption was quite ridiculous at dual-carriageway speeds. I think if you could do the same tests with the revs raised and under load (which you obviously can't) you'd find it really leaks badly.

I know you said you checked the breather pipes but what breather system do you have? Do you have the pipe from rocker cover to air filter and another open pipe of swan-neck shape on the tappet chest cover? The swan-neck pipe is often blocked solid. There are various different breather systems that were used over the long production period and sometimes they are mixed and matched with bits from different systems on the same engine.

Stephen

[kevin s]

What engine is it? Compressions can vary quite a bit so are nor definitive in their own right, a leakdowwn test is better.
Only other thing I can think of is they have managed to somehow disturb or crack the backplate changing the clutch causing the oil pump cover to leak.