Manifold Work Tips?

[mogdobz]

Hello all. I'm a new owner of a 59 Moggie and new to classic car ownership. I've done mechanical work on things in my time - but I'm young (the car is more than twice my senior ) and I'm getting my bearings on this lovely 1959 lady, so general advice is appreciated!

The car has unfortunately been gassing me a bit. Windows open... I can feel puffs of gas around the back behind the carb out from the manifold and, more obviously, it's very stinky.

I gather exhaust manifold work can be a bit finicky (Series III 948cc A-Series, to which someone bolted a 5-speed box) necessitating the carb be removed as well in order to replace the manifold gasket. The last owner didn't have a work log book so I couldn't say when the exhaust manifold was last looked at, although it does have some newish looking patching paste in a few spots (not that that's very reassuring). The pipe below leading under the car looks in decent shape.

Has anyone got tips for finding new manifolds if necessary, and on removing, patching, sorting decent gaskets, and re-fitting it?

I have the Haynes and a copy of the workshop engineering manual - both describe the process. All the same, if the work is slipperier than a greased member of parliament then it's also appreciated if the advice is "leave it to a professional"!

Thanks in advance

[geoberni]

Removing the Carburettor, and refitting it, is quite easy, I would say the fiddliest bit is reconnecting the Throttle and Choke Cables correctly. Especially the bit about twisting the Choke Cable, or 'mixture control' as the Workshop Manual calls it (see fig B18 in the Manual).

Perhaps 'famous last words' but I don't see any reason why the manifold should cause you any problems.

Do you know if you've got the 1 or 2 piece manifold? If the manifold is faulty, and it's not just a gasket, spares are available.

[Andyhereford]

It is not simply a leak between the manifold and the exhaust? I found it a bit fiddly to get the top tube of the exhaust pipe securely lined up and clamped to the exhaust manifold….had to get someone ( my grand son) to take the weight of the exhaust pipe / silencer while I lined up and fixed the clamp.

[myoldjalopy]

You don't need to remove the carb, just release and tie the manifold out the way with the carb, exhaust pipe etc. still attached. The Exhaust pipe joint may be compromised doing this though. If the pipe joint needs to be re-made, jack the pipe into position before fitting the clamp.

[mogdobz]

Thanks all, very helpful. It could be the join between the pipe and the manifold so I'll have a look at that - and will jack up or get help to hold the exhaust pipe. Good to know the carb may not need to be removed as well if done properly but we will see what happens on the weekend...

[myoldjalopy]

Definitely worth checking to see if the leak is in the joint between the pipe and the manifold before resorting to pulling the manifold off. That joint is a favourite for blowing - the standard clamp is not the best design. ESM offer a more robust version: https://www.morrisminorspares.com/engin ... th-p830073
With the engine running you should be able to discover where the leak is. Just remember that area gets very hot!

[mogdobz]

Hello all. Thanks for all your help and tips I was able to find that the issue isn't the manifold (phew!), but much more straightforwardly the exhaust pipe to manifold seal had come loose and was liberally gouting fumes directly into my lungs. I jacked the pipe, took the old stuff off, cleaned the area, sealed it with gum for some extra peace of mind, and then fastened the clip back on. Easy work and now the car is a very happy lady, and my lungs are safe!

Interesting note is that the old exhaust fastener was noticably thicker steel than the one I bought new (part GEX7046 from DMG), so I cleaned the old up and reused it since it didn't seem damaged. The bolts supplied with the new one wouldn't have been long enough to house the accelerator cable return spring, too - maybe because it's an MG part being sold as MM compatible.

[svenedin]

Might also be worth checking your air filter. I had a blow between exhaust and manifold for a while. I discovered the air filter was choked with soot from that blow.

I don’t know what clamp DMG supplies but ESM supply an updated and much improved cast manifold clamp that was originally made for MMC Bath.

Stephen