Morris Minor Owners Club

Hello.

Originally i thought my gearbox was the problem (Growling upon light to hard acceleration)

It turns out that it is actually the engine.

When hot the oil pressure drops to around 50-55lb and 20-25 when idling

Could it be the big end bearings or the camshaft bearings.

It uses 500ml of oil every 200 miles

James

the oil pressure sounds good are you getting a knocking noise when the oil is hot and the engine is under load eg accelerating in 2nd .

yes but through all the gears really. when its hot the oil pressure drops from 65 when normal to around 50

it cant be the gearbox because when it press the clutch and i rev the engine it sounds really grrrrrrrrrrr

James

Even though that oil pressure is not 'desperate' - it sound a bit like worn main bearings ! But - are you sure it's not just intake noise - or an exhaust leak ? Or the exhaust pipe rubbing against the floor ??

500ml of oil every 200 miles isn't good at all.
It sounds like a pretty tired engine.

Rings and shells should sort it out, as long as the bores aren't too badly worn.

Hello BMC and Markyb

Those were the first things i checked. I made sure the exhaust was sealed and adjusted the exhaust straps etc.

When i changed the headgasket i noticed the bores had honing swirl marks does that mean someone has deglazed thebores already would they take another honeing.

I dont recall any sideways movement in the pistons.

It is running on std pistons as far as i know. The bores didnt look that bad so maybe they just deglazed the bores and then put them back in without putting new rings in.

To change the main bearings do i need to take the sump off and undo the con rod bolts etc with the head off and push the pistons out of the bores

James

That would be the 'big-ends' - for mains, you can change the shells on the centre main in situ, the front main also if you remove the timing chain, but rear main only with engine out. Even thn - it's not usually worthwhile doing shells without grinding the crank. Just money down the drain. But your oil p is not that bad - so I would certainly put up with it. Maybe sort out another engine - and then swap over.

I dont recall any sideways movement in the pistons

But did you check from side to side and front to back, I know the oil is a bit excessive but is the timing ok as this can make the grumbling worse if its out a bit.

i will check the timing.

I have a spare engine that i bought last month that was rebuilt in 99 and has only covered 30 odd thousand miles since.

James

There's the answer! Check over the 'new' engine - and swap it in if ok.

The question is: where is the oil going?
Unless you are laying down a smoke screen worthy of a battleship then it must be leaking out.
I'm 99% certain you can replace the main bearings without removing the engine.
The top thrust washer DOESN'T have a tab on it so you can push it round and out of the engine.
This gives enough room to remove the rear main bearing carrier and slip a new shell in place.
A minimal amount of brute force might be required.

Signs of cross hatching on the bores are very good news.
I'd only pop a piston to get an idea what has already been done.

I have just cleaned out the closed circuit breather which sits on top of the inlet manifold. it had some black gunge inside but not loads. there are traces of clean engine oil.

there was no wear ride on the top of all four bores.

So it seems its a std bore engine which i find very very difficult to believe for 93 thousand miles.

James

Not impossible, but unlikely.
Probably someone has glaze busted the bores and fitted rings.
Drop the sump and the centre main bearing.
If it appears to be made from copper, you need main bearing shells.
If it is grey all over then look elsewhere.

The question still remains.
Where is the oil going?

Does it smoke like a chimney or does it leave a puddle wherever it goes?

I have set the timing with the bulb method.

I take it copper means its completely worn and grey means life left in it.

It smokes on startup so valve stem seams are needed but i cannot see blue smoke when driving unless its minute.

I have noticed a small drip from the oil filter housing (mini style oil filter conversion.)

I think it may be the pipe from the block to the oil filter head.

James

Bad advice above i'm afraid re main bearings - you CANNOT change the rear main while the engine is in the car. Yes - the ecntre main can be cahnged, and the front main (IF you remove the timing chain) - but NOT the rear main. So there is little point changing any unless you can change them all. If it is the mains rumbling - the shells will be well gone, and it will be a miracle if the crank is not worn to some degree. The valve seals have little to do with oil consumption - yes, everyone grasps at that straw - it's the rings that are worn, probably not helped by some crankcase pressure. Run the engine at fast idle until hot - then remove the oil filler cap. Is there a plume of smoke/fume ??
You have another engine - check it's bearings - if ok - swap engines !