Exhaust Manifold 'inner sleeve' bodge

[MarkyB]

I know what I want - an exhaust paste that stays flexible.

You can use silicone bath sealer etc. Its very heat resistant.
I've used it on bikes and cars before now with good results.

For some reason it doesn't do the trick on the Minor I have at the moment
I'm going to try the foil bodge next time I redo it.

I wonder if you could use something like engineers blue so you could see where the flange is actually fitting.

[aupickup]

but the point is we should not have to bodge to make an exhaust fit

[rayofleamington]

but the point is we should not have to bodge to make an exhaust fit

If the manifold face has suffered damage over the years, sealing is always going to be a problem.
If the exhaust just doesn't fit, then it's not much different from many other parts - which is why the MMOC working group needs to be properly suported.

[Willie]

If your bodged up joint has failed already then obviously it is able to move therefore it is not properly clamped solid. Perhaps the belled out section of the down pipe is just not deep enough to be gripped securely by the exhaust clamp? Alternatively, the champhered section of the actual exhaust manifold may have been refaced in the past so that it is actually undersized? You don't need a flexible sealant because there should be no movement of the joint possible.

[Packedup]

I'm sure this is down to the clamp and/ or engine movement.

I hate to suggest yet another bodge, but how about running an exhaust flexi in the downpipe? That would reduce the forces at the flange so the clamp mainly just has to keep the gasses in, and not support the system anything like as much (assuming the extra mount you've fitted keeps everything high enough).

[Willie]

To my mind an extra exhaust clamp would only useful if it was SOLID as
opposed to a flexible strap and was attached to the same section as the exhaust manifold i.e. the engine/gearbox unit. In that way,once the exhaust joint was assembled and the solid clamp was also bolted up the down pipe and the manifold would, in theory, become one solid piece.

[Packedup]

I was meaning a flexible bit of exhaust pipe (hate them myself, but they serve a purpose I suppose). Then the hangars could take care of the weight of the system, and the flexi would reduce the load on the joint through engine movement.

Though I totally agree (and suggested early in the thread) that a solid support from the bellhousing ought to do the job. The key thing to me is the exhaust can seal until driven for a few days, then it leaks. So I suspect engine movement/ vibration is causing the failure, whether there is an underlying issue with the flanges or not.

Actualy, if the Minor doesn't have such a support as standard, could it be the exhaust mounts are too tight/ short/ not flexible enough? Obviously the exhaust would have to move to some degree, and maybe it's too restricted? Or the engine mounts and steady aren't as good as they could be of course.

I'll happily take a look and try and work my bodgery on it in exchange for somewhere to stick a few boxes of junk!

[dunketh]

I've emailed you wrt junk storage, theres plenty of space available.

Back to the exhaust, I took the system off on Saturday and dropped it into a mate. He welded up the collar as this had split so obviously wasnt happy.
I refitted it, done the clamp up 'FT' and it seems fine at the moment. Time will tell of course.
As for the bellhousing mount, I might see if I can find an MG parts place that'll just sell me one without charging me comedy postage.

[Packedup]

If you hadn't flogged your late 1275 Midget manifold...

I've been thinking - Surely a bit of fairly small (1"x1" and couple of mm thick) angle iron could be used to make a solid bracket? Drill a couple of holes fopr the bottom bellhousing bolts, then bend it as required to line up with the exhaust. Remove the end inch or so of the vertical face leaving a flat bit, which you'd drill and then run one end of an exhaust U type clamp through.

That'd pretty much mirror the Midget design but using just one bit of metal and a clamp. The only problem is I don't know if there's a clear path between bellhousing and exhaust under a Minor - Never spent much time messing with that area.

[simmitc]

Rob Thommasson has published an excellent Technical Tip in Minor Matters on a couple of occasions: Take a pice of copper wire (solid core, a bit of earth wire from 2.5mm twin & earth cable is ideal) and make a ring that sits just below the flange of the pipe. When fitting the clamp ensure that it seats on both the manifold and the new bit of wire on the pipe. Tighten the clamp. Job done, simple, cheap, clean, it works perfectly every time.

NB overtightening the clamp can distort both the clamp and the pipe. If anything is really worn then replace it with new.

[jonathon]

We use a proper silicone exhaust paste which allows for easy assembly, and it does not harden. Its not cheap at £15 a tube but its the best exhaust paste we have tried, and is used by most good exhaust fabricators. I'll post details if anyone is interested.

[MarkyB]

I've given this a bit more thought and I'm wondering if the reason I can't get silicone to work on this car is that it has excessive back pressure which finds its way out of the weakest joint in the system which has always been the manifold/ exhuast joint.
I'm fairly sure that early minis had the same problem so its definately a design flaw.
I hadn't heard of the copper wire bodge before. I'll try it this week time permitting.

[rayofleamington]

That'd pretty much mirror the Midget design but using just one bit of metal and a clamp. The only problem is I don't know if there's a clear path between bellhousing and exhaust under a Minor - Never spent much time messing with that area.

It's pretty easy to do - there's room inside the engine bay to get from a bellhousing bolt to the exhaust (I added one of these brakets on a previous Minor)