Exhaust Manifold to Front Pipe Joint

barker_001 · Post by **barker_001** » Tue Apr 21, 2026 15:29

I've bought a complete SJ stainless system to replace the old exhaust on my SE which is mainly held together with repurposed Peugeot clamps, sealant, and good fortune...
Most of it looks relatively straightforward and it will probably be a case of cutting the rusty old bolts / brackets and lowering the parts away, but I'm a bit concerned about the manifold joint. Has anyone got any experiences of separating this joint and if so what are the pitfalls? How does it tend to come apart - do the nuts just unscrew or do they need more persuasion? Is there any possibility of the manifold flange getting damaged? I've got a new gasket, studs, and nuts to hopefully cover most eventualities.
Thanks in advance...

Post by **Hawaiis0** » Tue Apr 21, 2026 17:00

I take it you are talking about the twin downpipe to the manifold with 3 studs?

If so then it comes apart easily once the nuts are off. Only issue will be if the studs are bent which will pinch the flange creating a resistance.

rbgosling · Post by **rbgosling** » Wed Apr 22, 2026 14:43

Access from underneath is... achievable. You'll benefit from a long socket extension, preferably one of the ones that allows the socket to wobble about a bit, kinda like this one:

Mine has usually come undone without needing a stupid amount of force, but if yours has been undisturbed for a long time your experience may differ.

barker_001 · Post by **barker_001** » Wed Apr 22, 2026 18:10

Thank you gents, that sounds quite feasible then.

Concerning the wobble bar Richard, would a 3/8" or 1/2" drive be better? I see you can get them in 200mm and 300mm lengths too. It looks quite tight down there so the 3/8" might be easier provided I can get enough force behind it.

Pete Boole · Post by **Pete Boole** » Wed Apr 22, 2026 19:09

The biggest problem could be shearing the studs as you undo the nuts. This will mean removing the manifold to helicoil the holes. Hope this doesn't happen!!

Pete

rbgosling · Post by **rbgosling** » Wed Apr 22, 2026 19:47

barker_001 wrote: Wed Apr 22, 2026 18:10 Thank you gents, that sounds quite feasible then.

Concerning the wobble bar Richard, would a 3/8" or 1/2" drive be better? I see you can get them in 200mm and 300mm lengths too. It looks quite tight down there so the 3/8" might be easier provided I can get enough force behind it.

Mine is 1/2” drive and fits fine.

Marten · Post by **Marten** » Wed Apr 22, 2026 21:19

Pete Boole wrote: Wed Apr 22, 2026 19:09 The biggest problem could be shearing the studs as you undo the nuts. This will mean removing the manifold to helicoil the holes. Hope this doesn't happen!!

Pete

If you break a stud the threads are still there. You'll probably only need a helicoil if you wreck the threads trying to get the remains out of the manifold.

Problems with removing manifold nuts etc are:
Nuts having lost their hexagon through corrosion
Nuts corroded onto the studs.
All this with limited access.

Don't use a 12 point socket, heating the nuts red hot to break the corrosion helps, and if the nuts turn take it easy and go back and forth with lubricant . And use proper exhaust nuts when re-installing

The Lotus Grand Tourers

Exhaust Manifold to Front Pipe Joint

Exhaust Manifold to Front Pipe Joint

Re: Exhaust Manifold to Front Pipe Joint

Re: Exhaust Manifold to Front Pipe Joint

Re: Exhaust Manifold to Front Pipe Joint

Re: Exhaust Manifold to Front Pipe Joint

Re: Exhaust Manifold to Front Pipe Joint

Re: Exhaust Manifold to Front Pipe Joint