Having been out on a Sunday bimble in the zed I was aware of a blowing exhaust on my return, sounded like the downpipe to manifold joint so ordered a new gasket. Came to fit it a while later and realised on inspection that it was not the gasket but the pipe had actually split at the flange .I eventually took the exhaust off (a one piece genuine BMW system) and found not one but both pipes had fractured at the mounting flange. After some thought it became apparent that there should be some sort of bracing bracket to tie the exhaust to the engine/gearbox preventing relative flexing between the two. There was no such bracket when I fitted the replacement engine in the car (see newbie thread). As a result when the engine flexes on it's mounts it kept pulling on the exhaust downpipe which eventually worked on the downpipe mounting flange causing the fracture evident in the photo. It transpires the exhaust is stainless steel including the flange and required welding up by an outside welder as I have no provision for stainless welding. To prevent a recurrence I made a simple tie bar out of 1/8 inch steel plate and exhaust clamp, this was to brace the exhaust downpipe to the gearbox to stop the flexing on the downpipe joint. Clearly the original had rusted away and disappeared.
The tie bar fitted in the following picture:
Moral of this tale? check your tie bar is there!
The tie bar fitted in the following picture:
