Crack on Casing around the Exhaust Joint

Has anyone developed a crack around the casing just where the exhaust connects onto it at the top. I was cleaning my downpipe at the front and noticed a large crack on the casing. I'll put a pic up later as my discription may not be so good - but wanted to know if others have it - is likely to get bigger and or if it should be something I should be worried about or not?? Its the first time ive cleaned the pipe so it could have been there for ages...

Yep, exactly the same. Started out like the photo, i noticed it about 4 years ago. Then over a year the crack spread left and back out, eventually a chunk fell off.

Result of this? Easier to remove the front pipe! No leaks either.

Mine looks just like that now - and I was trying to work out how to put up a pic... Thanks for the reassurance I wont bother now.

No problem. I panicked when I spotted it too, hence the photo to compare later.

Just keep an eye on it over the next while, if it hasn't made a bee-line for the cylinder block then you can breathe easy.

I don't know how mine started either, possibly over tightened header bolts.

[Sid Squid]

The exhaust header stub and the inner face of the exhaust port are corroding. When this happens the material expands a bit, with the results you're seeing. Remove the pipe and clean it up now and again if you want to stop it happening.

And, despite the fact that no leaks have occurred thus far, I suggest you do want to stop it happening.

[embee]

It may not be relevant in this case, depends on the detail around the blend between the stub and head, but a useful tip if you do get a crack starting is to drill a hole at the furthest point the crack has reached.

In theory the bigger hole the better, but something in the realms of 4mm dia is usually suitable.

This reduces the stress concentration at the end of the crack and stops (hopefully) it propagating further.

It's important you get it at the very end of the crack, i.e. so that the crack doesn't extend beyond the hole, otherwise it's a waste of effort. This usually means drilling slightly beyond the visible end of the crack.

This of course is on no use if you're drilling into an oil gallery or water jacket!

Couldn't you just get someone to cast-weld it

[northwind]

if it actually bothers anyone, I have a plentiful supply of barrels in the garage But tbh, it'd be a huge pain to replace.

[Sid Squid]

Originally Posted by Cloggsy

cast-weld

Originally Posted by Sid Squid

Welding with cast iron rods using a mig welder - I had my car exhaust manifold repaired in the same way