38 replies to this topic

[stevelane]

Ever since my engine rebuild I've not been able to stop my exhaust blowing so wanted to call on other peoples knowledge to see if I'm doing anything wrong

It's a 998cc mini city with a standard exhaust. The exhaust itself is good with no holes, it's always at the manifold that it blows.

I'm using fire putty to seal it but yet it blows instantly. Should I be leaving it for a certain time to let it set, the instructions just say it should set with heat.

Also how much should I use? Sparingly or liberally?

[coopdog]

It's because the engine is rocking,

Try changing the engine steadies, on on the block and the other on the gearbox,

And put lots of the sealant on,

If that doesn't help you might have to fit a flex pipe on it

[stevelane]

When you say change the steadies, are we just talking bushes?

[coopdog]

Yeah sorry the bushes

[stevelane]

They are fairly new but will make sure everything's right

[CityEPete]

Mine is the same but it's the engine mounts that are shot, I have an adjustable top steady which helps, as I'm stripping the car this winter I'm leaving it as is.

[RedRuby]

Have you tried a new manifold to exhaust clamp, presuming it's what I think is referred to as a bell type connection. Clamp with two halves that clamp round the annular rings on the exhaust down pipe and manifold. If so have you checked the condition of the annular ring on the manifold?

Edited by RedRuby, 23 April 2014 - 10:06 AM.

[stevelane]

Has had new engine mounts and a new clamp

[Dan]

Did you clean any old sealant off the manifold? It sets up pretty hard and will leave an uneven finish that prevents the two parts fitting closely enough for the clamp to work.

[stevelane]

Yeah I did but must admit it's not easy to tell down there so there could have been some left, although the last time I really for it with the wire brush to get it clean

I have checked the engine steadies and everything seems pretty tight but am happy to get new bushes after one more attempt.

The clamp is new but was quite cheap so I don't know if that could be an issue.

Can anyone give me advice on how much putty I should use and if I should start it instantly to cure or let it set then just harden it off?

Edited by stevelane, 23 April 2014 - 11:02 AM.

[Mini Manannán]

Gasket surfaces need to be immaculate or leaks will happen.  Use your sense of touch, it'll be more accurate than your eyes in this case.

[stevelane]

Have cleaned up the manifold and the pipe now, not a trace of previous sealant so I'm going to try again.

Still not been able to get an answer as to whether I should let it seal or start it straight away

[danie garry]

Have cleaned up the manifold and the pipe now, not a trace of previous sealant so I'm going to try again.

Still not been able to get an answer as to whether I should let it seal or start it straight away

 

the exhaust paste usually seals when it warms up and i think the directions on the tins usually say try and fit it after the engine has been running as the exhaust will be warm, iv used a heat gun before to get it to go off and it did work! you need enough to make a good seal, a nice even coating on the mounting face of the joint

if you cant get heat to it then i'd say leave it a few hours before starting

edit* even with it heated i'd leave it a little while just to be sure

Edited by danie garry, 23 April 2014 - 01:07 PM.

[stevelane]

Thanks for that

The exhaust pipe is back on, has now been a couple of hours but am hoping to take the car out tonight so I will give it another hour or so before trying to start it.

I did manage to get under the car and shine a torch up to the manifold before I cleaned it up and there were obvious areas with no sealant so my guess is I started it to early and it just blew the sealant straight out.

The instructions on the packet don't say anything about time, just that it cures when hot.

Let's hope it's worked this time and if not I will get some new bushes for the steadies and try that

[danie garry]

Thanks for that

The exhaust pipe is back on, has now been a couple of hours but am hoping to take the car out tonight so I will give it another hour or so before trying to start it.

I did manage to get under the car and shine a torch up to the manifold before I cleaned it up and there were obvious areas with no sealant so my guess is I started it to early and it just blew the sealant straight out.

The instructions on the packet don't say anything about time, just that it cures when hot.

Let's hope it's worked this time and if not I will get some new bushes for the steadies and try that

 

i'v had the same problem and nothing at all seems to cure it, its not the best design as theres way to much movement! i ended up butchering the whole lot and welding a slightly larger pipe to the manifold and then clamping the exhaust inside that, new cooper freeflow to go on now!