Blowing exhaust gasket

[Mr Spigot]

I acquired my 1952 MM in November (918 side valve USHM3 engine) and when driving it home, noticed a 'blatting' sound from the engine under load. When I got home I found the exhaust gasket between the exhaust manifold and exhaust pipe flange had disintegrated. I got a new one from ESM and fitted it, but that too disintegrated pretty quickly. The ESM gasket was made in Sri Lanka and and quite thin. So I ordered 2 more from the Morris Register which were much thicker, and fitted them both and tightened it all up. The joint was fully tightened with new bolts.
However, taking her for a run this morning, it soon became apparent that the gaskets had gone again and I am pondering a solution. Looking at the flanges, (see photo) they do not seem to sit quite square to each other, (larger gap to rear) which may be the cause of the problem, but I am not sure how I rectify this. I initially thought that fitting 2 gaskets would take up any clearance, but that obviously has not worked. The manifold is fixed and I cannot see how the exhaust position can be adjusted but would welcome any help!

[philthehill]

That gasket https://www.morrisminorspares.com/engin ... ly-p899626 is expensive and should last a lot longer than it is doing.
I suspect that the front pipe of the exhaust system in not aligned correctly and that is why the flange gasket blows.
How many pieces is your exhaust system?
If more than one piece I would slacken off the exhaust pipes to the rear of the front pipe and then fit new flange gasket and tighten the front pipe flange nuts firstly. This to be done without any loading/pressure on the front pipe from the rear pipes/silencer/mountings. Secondly tighten the rest of the clamps/mountings progressively. You may have to adjust the mountings to suit.
If you have a one piece silencer system I would be tempted to cut the front pipe from the rest of the system - fit as above and use a joiner to connect the front pipe and the rest together.
The exhaust may benefit from a flexible exhaust pipe joiner connecting the front pipe to the rest of the system.

[Mr Spigot]

Thanks Phil, that is really helpful. The exhaust is a 2 piece stainless system, joined just behind the silencer box. I will loosen it all up and detach the rear pipe and try again with a new gasket.
The ESM gasket is expensive at £12.60 + post, but the Morris Register one is much thicker and more substantial and costs only £6.98 + post. I will go with the MR one. If that fails, I will try the flexible mount option.