Morris Minor Owners Club

There is blue smoke from the exhaust on start up but not seen when running. The car goes OK and pulls well
with no apparent problems. The engine and gear box are on the original mileage of 97000. Is the smoke on starting the start of something big and is there anything worth doing at this stage? Andy.

At - 97,000 it's bound to be worn. The real test is with engine hot and idling - remove the oil filler cap and rev up. Is there a plume of smoke/fume?? And does the engine use much oil?

The engine does not seem to use an excessive amount of oil.I will carry out the tests tomorrow and report
back. Many thanks.

Only on startup means the valve guide seals and maybe the valve guides are beginning to wear down. When the engine is stopped, some oil seeps through the valve stem into the cylinder and produces smoke as it is burned when you start up the engine.

You could try new seals after doing the tests Roy recommended which shouldn't be too expensive since the oil in the cylinders will make it harder for the car to start eventually.

Still, prepare for a rebuild in the not too distant future; if the engine still runs well you could probably get away with just bearings, rings, oil and water pumps and new valve guides.

I put a new unleaded head on 3000 miles ago from EMS. I think this should have had new oil seals on. You
are right I will have to carry out a major overhaul soon but would like to keep it going for the time being.

In light of you fitting a head 3000 miles ago it might be an idea to check the head bolts are still tight just to eliminate the possibility of oil coming from there.

I'll check the head bolts tomorrow just in case. Thanks

As above - it IS very likely to be valve guide seals that are the problem. Ask the supplier.... Why on earth did you fit an 'unleaded' head?? But at 97k miles - I would keep going to get the 100k !

Every single cause I can think of for smoke on startup would have to be in the head or carburetor, but since the car is running well most probably the head so maybe you don't need a rebuild yet after all.

How can the carb cause blue smoke??

There is no smoke when the engine is hot , the oil filler cap off and the engine reved. The head bolts are OK.
I put an unleaded head on because at the time I thought it might help if I sold the traveller. It did seem to make it run better though ! Its looking like the valve guide seals need looking at which I will do if it gets any worse. I will certainly get up to 100,000 before any major engine overhaul.I think the engine reached 97000 because it always had regular oil changes. Many thanks for you time.

Yes - that's the answer = regular oil and filter changes. I'm sure it will be fine then if there is no fume. Disappointing though if valve guides/seals fail after only 3000 miles.....have to wonder about the standard of the work....