Old 323i exhaust manifold.

Post Sat Mar 01, 2014 6:53 am

I have just pulled the exhaust manifold off of my 323i in order to replace the gaskets. I have an early 323i(1984) and it looks a bit different to the ones on the later m20 motors. I have a spare manifold off of a later car and it is a bit different . Does anyone know the function of the small pipes that run from the air valve into the exhaust ports through the back of the exhaust manifold? Is there anything that should be done to them while the manifold is off?

Post Sat Mar 01, 2014 10:05 am

Air pipes are part of Australian market emissions equipment. Best thing to do with them is remove and blank off, along with all the other bits, depending on local regulations and whether or not you're a OEM type.

Post Sat Mar 01, 2014 3:33 pm

will blanking them off effect the car's running? what is their function? Can I remove the air valve as well?

Post Sat Mar 01, 2014 9:16 pm

Do you have this stuff as well? http://2009.bmwfans.info/parts/catalog/ ... ntrol_agr/

All of it can be removed (except the distributor vacuum advance tube) with no detrimental effects, as long as you blank off any connections into the inlet manifold.

Post Sat Mar 01, 2014 10:53 pm

I will go and have a look. I an guessing that the system is same with my 6 cylinder compared to the 4 cylinder in the diagram? Those steel pipes that run into the back of the exhaust manifolds are held in place by large screw in bolts that the pipes run through the middle of. I will get my son to put a weld in the central hole of these mounting bolts and then screw them back into the manifold. That should blank them off. I am guessing the idea of these pipes was to draw exhaust fumes back into the air box so that the fumes were reburnt, an thereby some of the particulate wastes removed form the final exhaust gasses. Would this be correct?