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BJ8 exhaust down pipe gaskets

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Jeepster

Jeepster

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I think I may have identified the cause of my rough running issues. ( poor idle and engine splutters at 3000rpm plus back firing)
The gasket that fits between the exhaust down pipe and the exhaust manifold has failed as I can see it blowing.
I fitted a new exhaust last year and it's done minimal miles since.
Have any of you had problems with these failing? Is there a better product I could hold of to replace the failed gaskets?
Or maybe I would be better off with a tubular manifold that fits directly to the head? Not sure if this will mate with my stock BJ8 exhaust system.
 
If you're not looking for the performance upgrade that a tubular header brings, stay with the stock exhaust manifolds. Also, headers usually don't mate with the stock exhaust piping.
 
Jeepster said:
...
Have any of you had problems with these failing? ...
Click to expand...

Fought this problem for years. Tried several sets of new brass nuts, new studs--SS and mild steel--and several types of gaskets. Either/both the gasket blew out or the nuts loosened (on one long trip just got in the habit of tightening the nuts every day--can be done with a couple long extensions and a deep socket.).

Finally solved the problem by a) coating the gaskets with high temp silicone (the copper-colored one) and b) double-nutting the studs with regular steel nuts (concours can stick it). Used anti-seize on the studs. 'Problem solved' as Edd China would say.
 
Bob_Spidell said:
Fought this problem for years. Tried several sets of new brass nuts, new studs--SS and mild steel--and several types of gaskets. Either/both the gasket blew out or the nuts loosened (on one long trip just got in the habit of tightening the nuts every day--can be done with a couple long extensions and a deep socket.).

Finally solved the problem by a) coating the gaskets with high temp silicone (the copper-colored one) and b) double-nutting the studs with regular steel nuts (concours can stick it). Used anti-seize on the studs. 'Problem solved' as Edd China would say.
Click to expand...

One re of the UK parts suppliers sells what looks like a premium solid copper gasket that looks favourable. Might give that a go. I will have a look for the high temp silicone.

Glad to hear you get wheeler dealers in the US too. Best show on the TV but they still haven't featured a big healey.
 
Try doubling up on the gaskets, maybe even going from the OE copper-faced type to the thicker ones used by most tube0header installations.

Either the mating surface on the cast-iron manifolds, or the steel down-pipe flanges is not smooth/flat, and the extra gasket thickness will accommodate that.

In the event that the cast-iron exhaust manifolds are removed, they can be surfaced, same as you'd do for a flywheel or cylinder head (I wouldn't pull them just for this though, not without doubling the gaskets first).

Definitely agree with John Turney; if you're not souping it up, the stock exhaust is far easier to live with__on many fronts!
 
I have ordered new down pipes and a couple of sets of gaskets. Went for the better quality copper faced gaskets rather than the silver ones with holes in.
The tubular manifold sounds like too much hassle as I am not looking for extra performance - just an easy life.
 
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