Mi16 Exhaust Manifold Differences

[Jon_Bmw 13]

Firstly I did a search and couldn't come up with anything related to this 'issue.'

 

The flange I am referring to during this post is the one on the exhaust manifold, but the collecter side, so where the 8 pipes collect into 1. More specifically the diameter of the round collector.

 

The manifold on our 1.9 mi16 D6C engine has a significantly smaller diameter flange/collector than either the two spares we have and the brand new gasket that I have just bought. Its about 2mm smaller at a guess(its still attached to the engine at present). This means with the current gasket I will never be able to acheieve a seal with it I don't think. The two spare manifolds I have the gasket fits very snuggly on one, and almost as snuggly on the other.

 

So did PUG/CIT make two types of exhaust manifold as I can only see one listed on the parts catalogue I have found on the internet. A difference of 2mm+ in collector diameter seems too much as a manufacturing defect doesn't it? Were these cast manifolds or hand made everytime?

 

The easy option on the face of it is to swap exhaust manifold over, but if its anything like 20 year old BMW manifolds you can get into a whole tale of woe with snapped studs in the head etc etc.

 

Anyone else noticed the differences before?

 

Many thanks

 

Jon

[jedibusa 0]

Did you ever get this problem sorted. The reason i ask is that i am doing an MI16 conversion and have found exactly the same problem.

 

The standard 16v manifold i have bought has a smaller diameter than my standard 8v downpipe and there is no way they will seal.

[Jon_Bmw 13]

No, I got a pattern downpipe gasket and it fitted snugly around the smaller collector in the end. I probably have a larger one kicking around that you can have for a few quid, but you'll need to let me know the dimensions just to make doubly sure...in case there are multiple size differences. :S

[welshpug 1,657]

I found that the XU10 Mi16 manifold flange was significantly larger than an 8 valve downpipe flange, enough for it not to fit, which is odd as many people say they do....

Edited March 16, 2009 by welshpug