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MG TD TF 1500 - Wow! What a Gasket!

I was test driving the other day and smelled serious exhaust fumes in the cockpit. Last night I figured I'd better check the exhaust flange nuts to see if they had loosened. To my dismay I saw places between the flange and the down pipe where gasket material was missing. Having a spare Moss gasket (the one on the car is from an unrecalled source), I dropped the down pipe and this is what I pulled out. Except for bends in the copper liners, it is exactly as removed. Completely disintegrated in less than 100 miles!!! I wish I could remember where I got it so I could alert the forum, but I cannot.


L Karpman

If the exhaust flange nuts had loosened, this kind of thing might happen. I fitted extra long brass exhaust nuts and wired them together.
Dave H
Dave Hill

Very common for the pipe flange to bend. Lay a straight edge across it to make sure it is perfectly flat. Make sure the nuts are actually pulling the pipe tight. Due to rust/corrosion, they can seem to tighten without pulling the pipe tight. Some aftermarket studs are not threaded all the way, (ie have an unthreaded portion) and the nut can run out of thread as well. Likely was not the gasket's fault. George
George Butz

Interesting guys. I did lose a nut in the first 25 or so miles, and I replaced it. This time all 3 nuts were tight when I discovered the blown gasket. Is it possible the damage could have occurred in that short 25 mile period? If this occurs again, I will have to investigate the flatness of the flange. Sorry I blamed the gasket, when all along it could be just my issue. Oh well, lessons learned.
L Karpman

Larry,

In the past I used brass nuts to affix the downpipe to the exhaust manifold. However,I found they would work loose so I switched to stainless steel nuts and the problem disappeared. Certainly check
both the exhaust manifold and the downpipes flange for 'truth'. (flatness).

It may also be worth looking carefully at the quality of the stud threads where they go into the exhaust manifold flange.

Cheers
Rob Grantham
TF3719("Aramis"),TF9177("Athos").
Rob Grantham

Rob: Both the manifold flange and the down pipe flange were checked when I had a machine shop remove the jet-hot coating there. The stainless nuts seem like a good idea as I don't believe they expand/contract as much as the brass nuts do. Do you, or anyone, know the thread size for the Moss replacement studs?
L Karpman

Still looking for the thread size for the Moss replacement stud nuts on the exhaust flange. Anyone?
L Karpman

Larry,

The thread size for the exhaust flange to manifold studs is 10mm x 1.5. Hopefully, the threads on nuts that Moss sell are the same.

I have used brass nuts with spring washers and had no problems.


John



J Scragg

I think the original studs on TD and TF exhaust manifolds were 10-1.5mm. About 11/2" in length. I am not aware of what Moss supplies
as replacements.

Cheers
Rob Grantham
Rob Grantham

Thanks guys!
L Karpman

This thread was discussed between 15/05/2017 and 17/05/2017

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