Morris Minor Owners Club

I have a problem with my newly fitted 1275. It’s the following configuration:

LCB Exhaust (Falcon, I now all the problems)
Mini spares Inlet Manifold
HIF44 Carb.

The first time I started it up he runs horrible. I did a compression test:
1 => 160 PSI
2 => 145 PSI
3 => 109 PSI
4 => 165 PSI

It was obvious that I had a problem with my third cylinder. I did a cylinder leak test and concluded a blown head gasket between 2 and 3. After taking off the cylinder head I was right. Because the head was of I grinded the valves and mounted a new head gasket. After this the compression on third was 140 PSI. Not perfect but better. The end result: Its is still running horrible. The strange thing is that the problem is in the fourth cylinder. When I take the HT lead off there is no change in refs. Also the manifold pipe from this cylinder is “colder” compared with the other two. I have a good spark and I can smell vaporized fuel. The spark plug is a bit wet.

All the components are there: Compression, spark and fuel. The only thing I didn’t check is a blocked manifold pipe from on the LCP part.

Any suggestions??

This is similar to a problem I had on my 1098cc recently but between 1 & 2, 1st I changed the leads as the same as your symptoms on 2 this made no difference (I assume you have checked this ) the gasket was indeed at fault and I checked the head for flatness just in case and the valves were fine, on reasembly improved compression but still the same problem, on tickover you could see the car twitching. Next tried a different manifold in case but no difference, so off with the head again and could find nothing wrong at all on asking a pal he said maybe it had developed an internal crack or something, so with a spare head he had a swap was done and the problem was resolved, so in my case it was the head but as yet the old head has not been checked to find the fault but something is not right with it.
So start with the plug leads and dizzy cap in case.

Duff plug - try another - or duff HT lead or bad connection at dizzy cap or at the plug. Definitely got the leads on correct order - 2134 anticlock around the dizzy ?

Thanks all,

I did already tried new plugs and dizzy cap. Leads are from my old 1098 and I just returned from the UK with no problems so the have to be correct. The leads are definitely in the right order. I checkt, dubbel checkt and re checkt.

I don’t no with a internal crack of this have influence on the compression. In general a internal crack causes the cooling system to get under pressure. I don't have a spare 1275 head so swapping it over is a problem.

bmcecosse wrote: 2134 anticlock around the dizzy ?

Or 4213, or 3421, or 1342 as the rest of the world says.

a

:D

In general a internal crack causes the cooling system to get under pressure.

It depends where the crack is, it may pay to have it tested somewhere to make sure.

But with a crack he must do something. I can do a cylinder leak test tonight but I still have my doubts about the exhaust.

If you have doubts about the exhaust you can try the old way of finding a leak by squirting some washing up liquid areound the area before starting and watch what happens when running if there is an obvious air leak the liquid will blow bubbles.

When I have my doubts about the exhaust I mean that the manifold pipe of cylinder 4 is blocked one way or the other. (production fault)

I just set my exhaust valve open and blow with 100 psi of compressed air into the cylinder. (with disconnected muffler after manifold) If there is no problem I can hear this in the pipe.

Ok, the mystery is complete now.

I took off the LCB exhaust complete and mounted the original 1098 manifold with the complete 1098 exhaust and carburettor. And guess what, it runs perfect. After that I chopped the inlet part off from a old manifold and mounted it with the minispares manifold en HIF44. Runs perfect now.

What is wrong with this exhaust? The fourth pipe is open.

Dunno - very very strange! Nice clean looking engine - and engine bay!!
The point of listing the firing order as 2134 is to emphasise that the engine pulls twice on the first port - and then pulls twice on the second port. Not ideal for making big power!

But probably capable of causing confusion amongst those who aren't specially interested in big power, but just want to get the plugs on the diz in the right order - hence the pointing out.

Thanks for the compliment.

The engine bay was the last part I had to do. So when I decided to change to the 1275 it was also time to clean the engine bay. Not a nice job when it’s 35 degree Celsius outside and 45 inside.

Here some pictures of the hard labour:

Wow - that IS a lot of work !! Well done.

Ok, engine and bay are ready now. It's still a mystry what is wrong with the exhaust. I'm gone send ESM a mail and try to swop it for another inlet. Main thing is that the engine runs Ok.

Certainly is a mystery - can you pass a welding rod right through it ok ? Was it possible that the inlet manifold near that exhaust pipe was not seated to the head properly - causing an air leak - or could the manifold gasket have been somehow obscuring the exhaust port ?

Ok, here a update.

This morning I assembled the rest and guess what. Engine wash rubbish again. After a cup of tea (I learned this on the forum, is good to relax) I decided that the only thing changed was the vacuum pipe for the breather. On the picture above you can see I taped it of. After refitting the pipe…… Problems. He just sucks to much air I think. I have a old mushroom type breather ting from a late 1098. maybe this will work.

One thing is for sure now. There is nothing wrong with the LCB..

michel wrote: After a cup of tea (I learned this on the forum, is good to relax)

Great to see that the REALLY important information is getting across

Great to see that the REALLY important information is getting across

Oh well with this damp weather I suppose I had better make another cup of tea.......