Morris Minor Owners Club

I remember mention of this on here before but wouldnt know where to start in the search options.

Basically my exhaust manifold to downpipe join keeps blowing. It maybe lasts a month, maybe a week. I've tried every paste known to me.
I've now put a front bracket on the exhaust to take some weight from the clamp. The bracket is an additional strap hanging from a spare bolt hole in the seat bracket thingy. Anyway, I digress..

The root of the problem seems to be the exhaust wobbling itself free. Ages ago someone posted about shoving a piece of pipe up the manifold and down the exhuast hence making the join 'un-bendable'. The pipe would have to be slightly less in diameter than the exhaust so as to make it a snug fit.

Does anyone have any pics of this or details of the pipe diameter and how to o do it?

Don't care about flow-arguments. Its a crap old standard exhuast, it aint gonna make a lot of difference.

Really, get the right sized clamp on it to start with! That'll help just a smidge.

I didn't realise your bracket ran from the shell - Try throwing something together off the bellhousing bolts (like on the Midget). The idea is not so much to bear the weight, but to make sure when the engine rotates the exhaust goes with it, so the bending motion is in the exhaust mounts and to some extent the main pipe, not the joint.

Really, get the right sized clamp on it to start with! That'll help just a smidge.

I straightened the clamp I have, the edges had splayed out and each piece had closed up a little. I never noticed before.

I didn't realise your bracket ran from the shell - Try throwing something together off the bellhousing bolts (like on the Midget).

There's sideways motion in my new bracket, its a rubber strap, seems to allow enough movement to compensate for any engine movement.

The 'cup' bit of the exhaust pipe has partly split away now anyways, making this sleeve idea more essential as it'll take any sideways stress away from the clamp. Once its fully split thats £30 for another system and this ones only been on there 18 months.

dunketh wrote: There's sideways motion in my new bracket, its a rubber strap, seems to allow enough movement to compensate for any engine movement.

The problem is the strain of the engine rocking causing the exhaust to twist is being placed on that little clamp/ cup - You want the exhaust to move around with the engine, but you don't want the force causing that movement to be put through the manifold/ pipe joint. Minis get the same problem if the exhaust isn't bolted to a bracket off the back of the gearbox, you get maybe a month or two then it starts to blow.

I don't know if the Minor has a gearbox/ exhaust bracket as standard, but it certianly wouldn't hurt

The 'cup' bit of the exhaust pipe has partly split away now anyways, making this sleeve idea more essential as it'll take any sideways stress away from the clamp. Once its fully split thats £30 for another system and this ones only been on there 18 months.

Get it gummed up till there's a decent autojumble round here, and try and hunt down a s/h lcb for a fiver (I've heard such things exist). Problem solved

And look on the bright side - You don't have two long bolts and a threaded stud, and a stupid sealing ring that falls apart...

No need for extra brackets - honestly, a good manifold (inspect it to see if it's damaged at the bell end) with a good pipe (used to be able to buy short repair sections for the Mini with new cup end) and a good new clamp with a smear of exhaust paste and it WORKS.

As BMC says you must ensure that the 'lip' on the actual exhaust manifold is in good condition and not burnt away in places. The exhaust clamp MUST be of the two bolt type too. I once had the belled out end of the exhaust down pipe break off completely but by beating the broken
end out to replicate the original shape I was able to make a gas proof
joint without the use of exhaust paste. I have never needed to use this sealer and my present stainless joint has been leak proof for about ten years with no sealant used. It is possible in other words. I assume that you are satisfied that the engine stabiliser rod is preventing excessive movemento of the engine?

and try and hunt down a s/h lcb for a fiver

I just won one on ebay for £16 :p

Before joined the two I made absolutely sure the manifold cup was completely clear of deposits. it is easy to mistake a layer of jointing paste for cast iron when it's discoloured and worn smooth - especially on the sied facing the block. I used a Dremel type drill to get it clean and cleaned out the clamp inner face too.

I've cleaned it completely and both faces have been perfectly smooth.
I thnk my initial problems have been with the clamp not being good.
Oddly my exhaust has 'sagged' where the downpipe goes into the silencer. Theres no signs of damage, its just 'dropped' for some odd reason.
Anyway, I'll sort it out one way or other. Cheap LCBs are for the lucky few.. everything I watch on ebay gets bid up to silly amounts in the dying minutes.

If the clamp isn't cleaned out the manifold and down pipe flanges don't sit in deep enough and the clamp doesn't get a good purchase.

One some cars the exhaust manifold seal is easy - on others it's a nightmare.
I've tried a LOT of things over the years, but next time I get a problematic one, I'm going to change the manifold! As the exhaust swings around if/when the clamp gets loose, it wears the manifold face and that probably contributes to future problems.

The extra steel bracket to the bellhousing bolts is certainly a useful way to increase the reliability of a troublesome exhaust joint.
I've also used the copper wire trick recommended in Minor Matters a few years ago - that also seemed fairly useful.

Here's mine from a couple of years ago. Still holding up.

http://www.morrisminoroc.co.uk/index.ph ... aust+bodge

Cool! I did think of wrapping the whole joint in tin foil so as to make a kind of paste sandwhich but I thought it would just burn away.
I'll definately try this method next!
I still cant get my head around comments about not using any paste at all - surely this would only work if both mating surfaces were 100% flat - almost polished?

Well, originally the surfaces were smooth!! I have owned five minors and have never needed any sealing paste on that joint. Perhaps I should be in the Guiness Book of Records!! The trouble is that if the car is run with a leaking joint there the escaping gasses burn away the cast iron lip
usually at 180 degree places where the small gaps in the exhaust clamp
are not actually pressing the two faces together.

well the exhaust i got is such a bad fit anyway
but the suppliers have agreed for me to take it back and a refund will be given, although it is fitted on my van

I assume that the basic problem is that over the years the reproduction parts have been from copies of copies of copies so that any initial slight discrepancies have become worse with each batch. The angle of the belled rim and even the angles on the exhaust clamp are critical. It would be interesting if someone could unearth an original(fat chance)
system to see how gas tight that was. I never owned a Minor from new
so do not know if the factory supplied them with paste on the joint.

I might have fixed it now, using a variation on the tin-foil plaster bodge. Time will tell...

I used a GunGum silencer repair bandage. In the kit they supply a thin bit of metal 'foil' and an impregnated bandage strip.
I smeared the exhaust mating surfaces with paste then jacked the exhaust up tight. I then covered the tin foil strip in paste and formed it around the joint with my fingers.
Then I wrapped the entire thing in the exhaust 'bandage' strip. Starting at the manifold then wrapping down over the joint and about a quarter of the way down the downpipe. I pulled this super tight (its slightly stretchy)and made sure the end stopped back over the joint area. I then put a standard two-bolt clamp over this area so it compressed the bandage and probably the metal stripe beneath it too.

Theres no way that suckers moving now! It looks like a mummy's arm wearing a bracelet!

I'm going to give it 15 days...

;)

Your optimism was touching, yet misplaced.

Its already died.

I know what I want - an exhaust paste that stays flexible - is that too much to ask these days with modern compounds and the like?
Can I find such a thing? Can I f...

should not have to bodge the manifold if the exhaust fits, but this is these days a very big IF

up till about 4 years ago i found the stainless steel exhausts fitted perfectly but now they dont

from my supplier the mild steel ones are a very good fit but stainless steel ones need some fettling and all you need is a good quality pipe bender and file ??????