Exhaust to manifold question

[RobMoore]

The other day on a short trip out I noticed that the exhaust was blowing. On inspection I found it was where it joins the manifold and when I removed the clamp I found kitchen foil and gun gum.
I cleaned all of this off both manifold and pipe and also both 1/2's of the clamp and on attempting to fit back together see that the pipe and manifold are the same size.
on inspection it would seem that in theory these should be held together by the clamp, however there is not a sufficient seal to prevent gases escaping.
It was suggested that using part of an empty bean can would do the job but alas I was unable to fit without thye pipe falling out once support was removed after fitting clamp.
I have gone with a very temporary solution of gun gu, and tin foild for now.

Engine is 1275 Marina engine, I have no idea on the manifold.

What is the correct mthod for fitting pipe to manifold? and how do I go about acheiving a good seal?
If anyone hada pic or two that would be super.

[bmcecosse]

Clean it all spotlessly - remove ALL old exhaust paste. Get a new clamp if there is any doubt about the one you have. Wipe a small amount of exhaust paste around the faces of the manifold and pipe - place a jack under the pipe - and push it up tight against the manifold with the jack. Another wipe of paste around the outside - and fit the new clamp - tight - but not over-tight! Remove jack. You need to make sure the exhaust system is properly held as it passes under the car - firmly but flexibly so it can move with the engine !

[Alec]

Hello BMCE,

correct me if I'm wrong (I'm sure you will ) as its a long time since I've used one of theses but I seem to remember that the vee of the clamp is assymetrical and needs to be fitted with the larger section down. This gives a better grip on the pipe.

Alec

[mike.perry]

If you have a Marina engine it is possible that you also have a Marina manifold and you are trying to clamp it to a Minor exhaust which is smaller than the manifold

[chickenjohn]

Clean it all spotlessly - remove ALL old exhaust paste. Get a new clamp if there is any doubt about the one you have. Wipe a small amount of exhaust paste around the faces of the manifold and pipe - place a jack under the pipe - and push it up tight against the manifold with the jack. Another wipe of paste around the outside - and fit the new clamp - tight - but not over-tight! Remove jack. You need to make sure the exhaust system is properly held as it passes under the car - firmly but flexibly so it can move with the engine !

I do pretty much this too, but find I have to re-seal the exhaust every couple of years. Maybe something to do with clutch judder and the state of the roads in East Kent!

[bmcecosse]

Rob already said they were both same size !

[RobMoore]

Yes both the manifold outlet and the exhaust pipe are th same size.
I think I am missing something here because even when both are connected and clamped in there is nothing actually sealing the join and thus emissions will always escape to some extent, in particular the end where the bolt is and the corresponding are 180 degrees where the clamps link.
Should there be some kind of coupling washer that fits in the well? (see diagram) please excuse my MS Paint skills lol [frame][/frame]
Very out of proportion but enough to convey my thinking.
The v shaped parts left and right represent the clamp halves.

Looking through the british leyland workshop manual 14th edition, I am either blind or there is no information pertaining the exhaust system

[alex_holden]

The mating face of your manifold should be a male cone which fits into the female cone of the exhaust pipe.

[RobMoore]

hehe if only it was that simple
mating surfaces are as my little diagram sadly.

[bmcecosse]

Well - the end of the manifold should have a rounded 'ball' section - which fits nicely into the cone of the exhaust system. Can only suggest it is broken off ? Any chance of a picture ??

[RobMoore]

Garage is a little small to work in and rain atm.
Will take it apart again when I get a chance and take a pic or two

[RobMoore]

This is the item I think I need http://www.minimania.com/web/Item/GEX7193/InvDetail.cfm
It would fit between the manifold down pipe and the exhaust.

[bmcecosse]

Well - IF you have the Spridget '3 stud mount' manifold ! I suspect that was used on the Triumph 1500 engined Spridgets - certainly not on A series engines.

[Declan_Burns]

You could try this as mentioned in the technical tips section. http://www.mmoc.org.uk/index.php?page=336
It's a bit of a fiddle to fit but it worked for me. I also found that the old clamps are much better than the repro ones.
Regards

[alex_holden]

One of the traders at the National a couple of years ago was selling cast steel clamps; they work a bit better than the pressed steel ones because they don't distort. I did subsequently have a manifold break off at the point where it was clamped though; I suspect I over-tightened it.

This rather dodgy photo is the best I could find that shows what the manifold mounting face should look like:[frame][/frame]

[Declan_Burns]

Here's a photo of the cast steel clamp and you can also see the home made adjustable bracket which stops the exhaust rattling against the aperture.[frame][/frame]
Regards

[RobMoore]

Alex mine does not look like that.
I'm wondering what manifold I do have now

Declan I like the idea of adding a steady bracket, on inspecting the rest of the exhaust I notice that the support bracket mid way along the underside is broken so there is not a lot holding it on and this is clearly not helping so will need to rectify that this week also.

[RobMoore]

This is the best picture I can get without taking off the carb.
BMC Ill seperate pipe from manifold at the weekend to get a better image for you.[frame][/frame]

[bmcecosse]

Well - that's a standard manifold - but it looks like it may be the larger bore 1275 manifold - and you are trying to 'mate' it with a small bore exhaust system - which is unlikely to work! Also - that looks like quite a large carb on there - but has someone fitted the standard air filter mount to it - with a hole that is smaller than the carb inlet ? Hard to see clearly from that picture - but if so - that will be seriously reducing the engine power!

[RobMoore]

My temp repair was more temp than I hoped for lol so anyway here are some pics.

The manifold downpipe. I can now see that it is not as I first though, the same sup shape as the exhaust but is in fact as others have suggested[frame][/frame]

The exhaust pipe. Whilst this looks to be a little bent out of shape it is the same size as the manifold down pipe so should all fit together nicely[frame][/frame]

The clamp[frame][/frame]

I cant get this to all to connect and stay connected, I am worried about overtightning so perhaps I need to tighten more?