Morris Minor Owners Club

Hi,
We went along to the Dorset MMOC Annual Rally last weekend and a couple of people commented that our air filter was in the winter position. I later opened it up to turn it around and found it full of soot. The carb piston was black and it was a bit of a mess.
A quick search of this forum and I discovered a relevant thread suggesting a potential leak in the exhaust manifold so I scheduled today to try and fix it.
I fully stripped and rebuilt the carb. The manifold surprised me slightly though as the inlet and exhaust manifolds are welded together as a single unit. I expected to find a couple if rings in the inlet to the head but these weren’t there and wouldn’t fit anyway as the holes are conical not parallel bored.
There were exhaust leaks in the centre and rear of the manifold gasket so these were cleaned up and new gaskets fitted throughout.
After setting the mixture and idle speed etc. a 25 mile drive was slightly quieter and slightly more responsive. The new plugs a nice biscuit colour.


The car still leaves its “I was here” calling card as a sooty mark on the floor whenever it starts. Is this normal for van exhausts? Or may it burn off now the leaks are fixed?

Is my one piece manifold normal?

Many thanks

Andrew

The manifold design is completely normal.

Looking at your manifold there are signs it has been blowing at the join between manifold and exhaust. This is a the most common place for a leak.

Check that there are no chips or cracks in the flared end of the manifold that fits in the exhaust "cup".

When fitting the exhaust a certain technique should be followed to ensure it does not leak. The later type cast manifold clamp is much better than the earlier pressed type. See: https://www.morrisminorspares.com/engin ... th-p830073

Make sure the mating surfaces are clean and there is no old exhaust sealing paste present. I use a smear of exhaust paste on the flare end of the manifold. Place a jack under the silencer near the front of the exhaust and raise the exhaust slowly with the jack whilst guiding the exhaust cup into place. It may help to have an assistant. Bring the exhaust and manifold together using the jack. Then fit the manifold clamp. Job done. Refit the carburettor, and air filter (you cannot see what you are doing with these in the way). Don't forget the throttle return spring and bracket.

Stephen

This is my manifold (1969). A late type for a PCV valve but basically exactly the same.

It is normal for the exhaust to splutter out some wet soot at a cold start due to the rich fuel mixture from the choke and the fact that burning petrol produces water.

Thanks Stephen!

Yes it was blowing between the head and exhaust manifold and slightly at the clamp. The clamp is a pressed steel variant.

The cup and bowl cleaned up very well and it seems to be a good joint with no exhaust paste. There’s no blowing for now. The top manifold flanges are quite corroded but there’s enough flat surface area all around to get a good seal.
The manifolds were a bit loose for my liking but there’s enough flat soapy water test now. I have added a better exhaust clamp to the winter shopping list. Hopefully as well as being quieter it’ll be more fuel efficient as well. The Midget has been way better on fuel.

I used the Jack method and the only frustration I experienced was refitting the choke cable with no space for my hand.

Many thanks

Andrew

You're welcome. Manifolds are easily come by so you might want to find a less corroded example. If you find a manifold with an inlet for a PCV valve it can be used for a brake servo instead. It would make for a neater engine bay than your current arrangement.

Stephen

I’m frustrated, getting grief from the owners wife about the sooty exhaust. Every time we start the car or arrive back from a trip the pickup is still leaving its sooty calling card on the floor.
I have double checked for any leaks in the manifolds and can’t detect any. I’ve checked the mixture with the lift pin and checked the plugs are biscuit coloured. It’s not burning oil but it is leaking out the sump gasket - I’m getting grief about that as well!

Anything else I could try?

Many thanks

Andrew

I used to work for a company in Loughborough. The commissionaire insisted that we all parked our cars nose in to the factory wall to avoid sooty spots on the brickwork.

Woe betide anyone who thought they could park nose out for a quick getaway...

Mine has absolutely always done this. Even with his rebuilt engine he does it. I think it is because he likes a lot of choke to start, so there's always going to be some soot and the design of the exhaust which tends to collect water where the exhaust goes over the axle. He likes to cough out wet oily muck until the exhaust system is properly hot.

Stephen

Same here. Usually a sooty patch on the gate behind the car, I think a simple solution is a sheet of cardboard.

Mine does exactly the same on start up, healthy engine no exhaust leak. As they say " they all do that sir"
Mines also sooty behind the back seat same side as exhaust

Thanks guys. It’s reassuring to hear they all do it. I’ll have to persuade the owner to keep running in the garage to an absolute minimum so that he doesn’t get too much grief. At least rain washes the soot of the driveway.

Many thanks

Andrew

I keep a plastic tray under the exhaust outlet and it's fitted with a turn down tip to stop it blackening the floor or wall on start up

Yes, mine does this on first start up as well - takes a bit of choke to get going after sitting overnight, but none needed once the engine has warmed up. There's usually a (very small) oil mark under the sump and a black smudge where the exhaust was.

As I live in inner London, and most of the vehicles now seem to be hybrid or electric*, I try to wait until the coast is clear before starting up. *I* know why there's a petrolly smell and a bit of soot coming out, and I know that it's short-lived, but I don't think it does the old car community much good if passers-by see/smell it, and assume that our cars are pumping out smelly clouds of smog all the time!

This may just be my paranoia to be honest, as I've had nothing but favourable comments from people when I'm out working on the car, from all ages - lots of people have told me that they make a detour so they can walk past my parking space, and lots of neighbours keep an eye on her for me.

Seb

*Enormous, Panzer sized electric vehicles which take up two lanes at a time, with bonnets so high that they could mow down an entire primary school and not notice. But that's another topic...

Napoleon Boot wrote: ↑Mon Nov 17, 2025 8:13 pm Yes, mine does this on first start up as well - takes a bit of choke to get going after sitting overnight, but none needed once the engine has warmed up. There's usually a (very small) oil mark under the sump and a black smudge where the exhaust was.

As I live in inner London, and most of the vehicles now seem to be hybrid or electric*, I try to wait until the coast is clear before starting up. *I* know why there's a petrolly smell and a bit of soot coming out, and I know that it's short-lived, but I don't think it does the old car community much good if passers-by see/smell it, and assume that our cars are pumping out smelly clouds of smog all the time!

This may just be my paranoia to be honest, as I've had nothing but favourable comments from people when I'm out working on the car, from all ages - lots of people have told me that they make a detour so they can walk past my parking space, and lots of neighbours keep an eye on her for me.

Seb

*Enormous, Panzer sized electric vehicles which take up two lanes at a time, with bonnets so high that they could mow down an entire primary school and not notice. But that's another topic...

Somebody did actually ask me about that at church on Sunday. An electric Panzer had blocked one of the exits from the churchyard by parking extremely inconsiderately. I had to do a ridiculous multi-point turn guided by the churchwardens. One of them said "does that clear eventually" meaning the slightly sooty exhaust when still using choke for a cold start. They also joked about the "mighty roar of the V12" that is the humble A-series

Stephen

panky wrote: ↑Mon Nov 17, 2025 1:00 pm Same here. Usually a sooty patch on the gate behind the car, I think a simple solution is a sheet of cardboard.

That is what I do too.....

No cardboard needed since I rebuilt the engine a couple of months ago. It took a while to clear out all the soot that had accumulated but nice and smoke free now and the gate stays clean

Ah ha ha! Simple solution - piece of card. Complex solution - rebuild engine!

I never make life easy of myself

Napoleon Boot wrote: ↑Mon Nov 17, 2025 8:13 pm Yes, mine does this on first start up as well - takes a bit of choke to get going after sitting overnight, but none needed once the engine has warmed up. There's usually a (very small) oil mark under the sump and a black smudge where the exhaust was.

As I live in inner London, and most of the vehicles now seem to be hybrid or electric*, I try to wait until the coast is clear before starting up. *I* know why there's a petrolly smell and a bit of soot coming out, and I know that it's short-lived, but I don't think it does the old car community much good if passers-by see/smell it, and assume that our cars are pumping out smelly clouds of smog all the time!

This may just be my paranoia to be honest, as I've had nothing but favourable comments from people when I'm out working on the car, from all ages - lots of people have told me that they make a detour so they can walk past my parking space, and lots of neighbours keep an eye on her for me.

Seb

*Enormous, Panzer sized electric vehicles which take up two lanes at a time, with bonnets so high that they could mow down an entire primary school and not notice. But that's another topic...

where are you in north central? I'm in bethnal green by columbia road...

dudload wrote: ↑Tue Dec 02, 2025 2:52 pm where are you in north central? I'm in bethnal green by columbia road...

I'm in Kentish Town near Tufnell Park - there are a few Moggies near me, a green 1098 Traveller and a convertible nearby, and a green two door saloon up in Highgate. There's also a nice one near my work in Marylebone, I often take a detour to say hello to it. Never seen any of their owners though.

I've also seen a bright orange Allegro and a blue Mini Clubman estate a few times on my road.
Daft but it makes me really happy whenever I see 20th century cars still out in the wild and doing what they were built to do.

Seb