project 1980 Austin Princess

[vulgalour]

It is!  It's probably the lightest clutch I've ever used, well worth the effort of changing the clutch really.

 

The Crab and Wedge is a seaside pub too, they serve crabsticks and steak chips in a paper cone for £1.50.

[Felly Magic]

Mojo level increased now too I bet. Hopefully you can sort the zorst and light gremlins out for not much poundingtons too. The beige & purple bastard lives again

[vulgalour]

Electrics are easy peasy, exhaust can be someone else's problem.  I cannot lose because I'm dutifully ignoring all the ways in which this car can and has gone wrong.

[Felly Magic]

Happy Vulg

[vulgalour]

Took the Princess to the local trusted exhaust place and the one guy there that knows his old stuff had a look.  The conversation was mostly "You're on your own with that one!", which was entirely fair.  Basically, the problems we're having getting it to seal is normal for this kind of exhaust and if it's a poor quality exhaust to begin with, my experience of it blowing eventually is also normal.  This is from someone that has fettled with BL exhausts since they were much newer than mine is and still fettles with exhausts now for a living.  His advice was not to waste the cash on getting them to try and seal the exhaust as they'd be likely to have the same success/failure rate as us anyway and it'll probably blow again soon after forking out to have it fixed.  I appreciate honesty like that, rather than being messed about, and it was reassuring to know that it is actually genuinely a problematic set up rather than us being inept.

 

We were given some tips on fitting, at least.  So far, we've done mostly everything right but actually getting the manifold-to-downpipe join sitting as snug as possible before sealant and clamps is the most important bit.  That might sound a bit daft, but given the design it's easy to think you've got it lined up perfectly when it's actually just a bit off, which in turn can cause the issues I've been having.

 

So, disconnect the blowing join, clean it up, make the flange as perfect as possible and wiggle everything about until it's lined up as close to perfect as possible without the clamps.  Then use some paste, tighten the clamps and get the rest of the exhaust secure.  It should then seal, or at the worst only blow a tiny little bit.

 

Ideally, replacing the cast manifold with a suitable custom one-piece banana bunch that goes into a good flexi joint and on into the rest of the system is the best solution.  Unfortunately for me, a custom exhaust is out of my budget currently so we just have to do the best with what we've got and do the exhaust when I can afford it.

[Felly Magic]

That is a real bummer there Vulg, sounds like you need a lottery win for the zorst issue

[Zelandeth]

Here's a possible halfway house - get a custom downpipe made to mate up with the rest of the system. At least if *that* is right the rest is more amenable to hacking into behaving.

 

I'm assuming this is the same daft type of flange setup as on the manifold to downpipe joint on the early Metros? If so, yes... it's a bloody stupid and utterly infuriating mess.

[Mr_Bo11ox]

I'm sure I've asked this before but can't remember what you said. Does your wedge have a clamp at the bottom of the downpipe that fastens the exhaust solidly onto one or more of the diff casing nuts??

[purplebargeken]

For something that could, in theory be really quite straightforward, an exhaust like this is a purely hateful, ball ache piece of fuckery.

[dozeydustman]

I admire your persistence with this car, Vulg. I read a few pages back you swapped the head. Did you keep the car's original manifold or use the one from the new head? Might be some tiny little difference between the 2 preventing a good seal.

[vulgalour]

Zel:  Yep, same system as on the Metros.  Custom downpipe would resolve it, as might welding the downpipe to the cast manifold and then splitting the downpipe further down.  Not sure how to deal with the carburettor since that bolts to the manifold.

 

Boll:  Yep, it has one, and it does seem to be doing its job on the side it's fitted.  Just annoying that you can't really fit one to do the same job to the other downpipe.

 

PBK:  Agreed!

 

Dozey:  It did this before I changed the head too.  In fact, when I first bought the car the exhaust was blowing and in our blissful ignorance we all thought that would be such an easy thing to put right.  My money is stil on this problem being caused by a rubbish factory design combined with a poor fitting exhaust.

[captain_70s]

Dozey:  It did this before I changed the head too.  In fact, when I first bought the car the exhaust was blowing and in our blissful ignorance we all thought that would be such an easy thing to put right.  My money is stil on this problem being caused by a rubbish factory design combined with a poor fitting exhaust.

Must be a BL thing, my Dolly 1850 always had a downpipe blow and now my 1300 has developed similar and has required industrial quantities of Gun Gum to silence...

[Mr_Bo11ox]

What's the clamp like that joins the downpipe to the manifold? IIRC each of the two downpipes should have a 4-piece clamp ie two inner bits and two outer bits. Are you using the right ones and are they complete?

[Mr_Bo11ox]

I remember this being a massive pain in the arse in my wedge days, but I'm sure I cracked it in the end.

[BeEP]

I've had the same problem with 1100s, Allegros & Metros, all of which use basically the same design (ignoring twin carb 1100s).

 

As Mr_Bo11ox says, 4 piece clamps are best, followed by 2 piece clamps using two bolts.  Worst, by a margin, are two piece clamps which use only one bolt (the other ends hook together).  Whenever I've bought a car with the latter then at the first sign of the joint blowing the clamps have gone in the bin.

[mat_the_cat]

I remember this being a massive pain in the arse in my wedge days, but I'm sure I cracked it in the end.

That's not going to help, it'll just leak out of the crack as well.

[Captain Furious]

What sort of joint is it? Is it one of those where one side is rounded and the other side is flared and they’re supposed to fit together like a ball and socket type affair and seal?

 

My Granada Cosworth had those on the cats-midpipe joint, there were two pipes to join which doubled the fun. It was unbelievably difficult to make them seal. You could eye them up meticulously, tighten them up to breaking point and it'd still blow as if the two pipes were nowhere near each other. Took us fuggin ages to get it right and then it was only pure luck. Frustrating to say the least.

[vulgalour]

Captain Furious:  exactly that!

 

The downpipe has a cup-flange that goes onto a sort of ball socket at the manifold.  There's two pipes, and they don't like to line up.  Each pipe is held together with a four part clamp comprising two inner shells of pressed steel, one outer pressed steel clamp half and one cast steel clamp half.  Originally it was two folded steel ones and they NEVER sealed, tried to replace them both with cast items from a Mini but they'd only seal if you used one half of the cast clamp and one half of the pressed clamp.  Don't ask me why, that's just how it is. The halves are then held together with the most difficult to access nut and bolt (2 of each per clamp)  you'll ever encounter and the whole lot has a bad habit of moving as you're tightening it up.

 

A custom exhaust is the only real solution, believe me.

[KruJoe]

I also remember this fun* from my Mini/Metro days.

As well as some tricks mentioned, I had some success with by lining things up as best I could, with Gun-Gum, and before nipping up the clamps, I put a scissor jack between the ground and the base of the down-pipe (with the rest of the exhaust fitted, to keep it in line). This just helps force the flanges together, without relying on the clamps to pull them in. HTH.

 

In the end I binned off that rig, and used a good old LCB manifold, and RC40.

[KruJoe]

PS... make sure all your engine mounts and stays are rock solid, to reduce the flexing forces on this PITA arrangement.

[vulgalour]

They seem good... but if they're not I'm screwed anyway since the mounts are NLA.  In other news, I need arrange a trip to Castle Cleland to chop bits off that Rover if they're stil available?

[RayMK]

My Stellar has a similar type of joint i.e. ball ended downpipe and cupped manifold + a two hole loose clamp which is supposed to clamp the downpipe up tight on the fixed mating half on the manifold. Despite the fact that I have good access, a longitudinal engine and only one pipe, it has proved difficult to seal for long. The most successful attempt involved wrapping 1mm diameter copper wire around the downpipe so that the loose clamp graunched this up when tightened, assisted by gun gum.  After running the joint up to temperature and re-tightening a couple of times it has held for a few thousand miles, though I can still feel (but not hear) exhaust gas lightly puffing on one side.  The exhaust experts' efforts (I've had two new exhausts in ten years) remained leak tight for barely a week in each case.  It's not just BMC that can't design a reliable joint!

[Mr_Bo11ox]

I know I sound obsessed with it but that connection to the diff casing is mega crucial. If you get hold of the exhaust near the Flexi and waggle it side to side does it slip inside the collar at all? If so that needs looking at, maybe put a metal shim inside the collar so it nips up really tight. Another thing is, is the Flexi joint still flexing? The ones that are like a ball and socket seize solid all the time meaning the manifold joint ends up doing all the flexing instead.

[Honey Badger]

Can you chop out the swivel section and weld/clamp a flex coupling in its place on the original exhaust? The current set up sounds a right pain in the arse.

 

Great thread Vulg, glad to see the princess back on the road again.

[Des]

It's an absolute bastard rejoining those flangy buggers, I'm still angry about the last Metro dual one I encountered 20 odd years ago. I used to find the only hope was to start at the flange join and work back, get it lined up nice and square, maybe even forced up with a jack and tightened till you hear the squark of the threads galling, then hang the system and pry / bend / space / kick the steady brackets on. An old Citrotten sphere is handy for batting down the high spots of the downpipe flange. I wonder if a turn of fibreglass tape, exhaust wrap or tinfoil impregnated or slathered with the red silicon around the join before the clamp goes on would improve things.

If ever there was a need for proper hard crumbly asbestos.

[alf892]

Dunno what all the fuss is about here! Jack the pipes onto the manifold and fit cast clamps at 90 degrees to each other.......and sure the lower bracket is fitted.

 

Stop fucking about!

[vulgalour]

You're welcome to have a go, Alf.  Everyone thinks this is a piece of piss until they have a go.

[Captain Furious]

The thing that utterly dumbfounded me with mine was not just that it was still blowing, but it was still blowing so severely that the exhaust might as well not have been connected at all. And then on about the 19th attempt using the exact same method all of a sudden it just sealed. Obviously it must have lined up perfectly through sheer luck/balance of probability.

 

If it hadn’t been for my experience with that I’d probably be in the 'what are you fucking about at' camp too

[vulgalour]

To expand on that and answer a few Qs...

 

Downpipe stay bracket - nice and solid.  You can't move the pipe in it and it doesn't wiggle.  It's tight enough that it doesn't come off the exhaust without a fight.

 

Flexi - it isn't seized but it doesn't have a lot of play.  It's the second weakest link in the system and it seems it should be a long wiggly one instead as standard.  I've had conflicted info on whether the ball or long-wiggle is the correct type so either BL used both (likely), or this is a bad aftermarket exhaust (also likely).

 

Jacking up - I've had the exhaust jacked up with the flange socket connected to the point that the exhaust is attempting to lift the whole car in the past.  If that can't seat it then I don't know what can, in all honesty.

 

Sealant/wraps - I've tried several, to no avail.

 

Honestly, fitting this exhaust is something that happens more by luck than anything else.  You either get it seated or you don't.   9 times out of 10 it isn't seated perfectly.  Of those 1 times it is, 9 times out of 10 it will work itself loose within a few thousand miles and start blowing again, no matter how tight you make the clamps, how much gunge you use or anything else.

 

 

If you genuinely think this job should be an easy one and you could do it and don't understand what the palaver is, please, be my guest and come and do it!  If you manage to get it to seal I'll even pay you because you're either some sort of wizard or have been blessed by the Machine God and I will be genuinely grateful for the intervention of the divine.

[Mr_Bo11ox]

They do suck massive grizzly bear wang those BL manifold joints to be fair, I know exactly this game as i have played it myself.