38 replies to this topic

[stevelane]

got pics!
first i cut off the cupped part of the down pie, if i remember rightly i cut it off where the pipe thickens, i then welded(quite crudely!) this part to the manifold


 
then i found a bit of stainless pipe that would slide over the piece that was now sticking out of the manifold and welded that to the down pipe

 
you can see the slot and the clamp to allow the stainless to clamp onto the modified manifold. i just put a bit of exhaust paste on the joint and clamped it on and it was perfect!
hope this helps

Thanks for the pics. Think itay be a last resort as I can't weld but happy to give anything a go to get this sorted

[Cooperman]

I bought my first Mini exactly 51 years ago and this was always a problem.

I ever only really solved it by fitting a 3-into-1 Cooper-type tubular manifold.

With the standard type you fit new clamp, new bolts, new pipe, new steady bushes, etc., it all runs fine for a while, then it blows again.

Maybe a short length of pipe welded into the top of the pipe and projecting about 1/2" into the manifold and sealed with Gun-Gum might help, but it would still probably blow after a while.

[stevelane]

I bought my first Mini exactly 51 years ago and this was always a problem.
I ever only really solved it by fitting a 3-into-1 Cooper-type tubular manifold.
With the standard type you fit new clamp, new bolts, new pipe, new steady bushes, etc., it all runs fine for a while, then it blows again.
Maybe a short length of pipe welded into the top of the pipe and projecting about 1/2" into the manifold and sealed with Gun-Gum might help, but it would still probably blow after a while.

I'm not even getting it off the ramps before it blows again

Did think a different manifold might be the answer but just don't have those sort of funds right now so will have to try the internal pipe as a temporary solution

[Cooperman]

One thing which does cause more rapid failure is a lack of support to the front pipe at the bottom of the gearbox. It's the relative movement between manifold and down-pipe which causes this premature failure.

Why not use a couple of extra clamps lower down and clamp the pipe to the diff case output covers in a couple of places or even to the diff case itself as well.

[stevelane]

Definitely worth a go, happy to try anything

[Cooperman]

If you make it impossible for there to be any relative movements between manifold & down pipe it should last a while longer than usual.

[emmybean]

Hey- Did you get this sorted? Wanted to just comment that I had this exact problem, had the one bolt clamp, blew, so I went and bought the two bolt clamp (expecting miracles) and nope, still blew. When replacing that though I did find out that the bracket that holds the front of the exhaust to the gear box was broken, putting additional strain on the exhaust clamp. so I rectified this with a new bracket (still cheap) but it still blew. SO now I want to give everyone a guide on how to fix this :) 

 

 

Step 1: Check its not the exhaust - this is a fiddly job and hurts your knuckles unless you're a girl with small hands like me :) so don't waste time by replacing the wrong bit! Be sure its this clamp :) which shouldn't be difficult to identify as the blowing will sound like its from there and will change if you fiddle with things - just listen carefully :)

 

Step 2: Check all brackets under the car are holding it on properly- one of mine was broken, and one was lose, so any repairs I did would soon be undone if I hadn't fixed it!

 

 

Step 3: Buy two bolt clamp - Approx £3- £3.50 - not expensive at all 

Buy new brackets if needed - the front bracket cost me £2 - all of them are under a fiver so again very cheap

 

Step 4: If any brackets were broken then jack up the car (on the subframe please!) and replace the brackets

 

Step 5: Place the Jack under the exhaust- pushing it up to keep it in the correct place

 

Step 6: Take off the air filter and remove old clamp- this can be fiddly for big hands, but no need to take anything else off- stick one hand with a socket down the right hand side and the other down the left with a spanner and fiddle until its undone.

 

Step 7: This makes the difference - take gungum from Halfords (again cheap- £5 i think?) and line the inside of the clamp with a decent layer- do try not to get any on the screw as when it hardens it will make it hard to undo but i got it on mine- oh well. Then (using a gloved finger for GunGum applications by the way) place a layer over the join between the exhaust and the manifold ( ensure the jack is pushing it up inline before you apply the paste).

 

Step 8: (This is underestimated!) Apply the clamp. This can be HARD- apply and make it tight! It will be made more difficult by the messy gungum sticking to you.

 

Step 9: Apply gungum to the edges of the clamp to seal the edges and stop any blowing from the edges- be sure to go all around the bottom and back on the clamp, trying to avoid the bolt again. 

 

Step 10- ALLOW TO DRY OVERNIGHT! - The BEST method I have found is to allow to set for three -four hours- check that it looks more dry / less wet and then run the car (IDLE ONLY) for about 5-10 minutes. Then allow to drive overnight. Take the car for a 10-20 minute drive and allow to rest ( perfect for me- take it to work then let it cure all day) and then its rock solid  

 

 

This seems to be the ONLY way really to stop a 998 blowing without changing the exhaust or welding. Its cheap and quick and works really well. and can be repeated. I havent had any problems with it yet, but if it starts to blow again a few months or a year in, then i will take off and repeat for pretty much free as i have GunGum left over. Until i upgrade to a new exhaust and manifold this is a great solution. Hope it helps everyone

[stevelane]

I think I got it sorted.

I put a small one inch pipe into the exhaust pipe, half inch into the pipe and half inch into the manifold (approx).

When I say I think I got it sorted is just because I've not been able to run it for a long period yet as I have other issues but it seemed to do the job

[emmybean]

Smart idea :) should be added to the above method for a good solid join!