Couple Of Questions About Fitting Downpipe To Mi16

[Dave_McC 0]

I've removed the flange and cut down my downpipe today - and with the flange bolted loosely to the manifold I slid the downpipe into place and marked round it to show the location. However, this appeared to have the flange not square with the downpipe. Given I didn't have the flange bolted up tight (and the new gasket as in place but not crushed), should I weld the flange on at a bit of an angle, or should I weld it on square and rely on the gasket to take up any misalignment?

 

Also, the downpipe to manifold fixing kit I've bought (OE Pug) has 2 lengths of bolts. Am I right in thinking the longer ones are the right ones to use?

 

And finally, when I trial assembled the nuts onto the bolts, they threaded on easily until the last thread of the nut started to engage on the thread of the bolt - and then they got really tight and needed spanners to continue. As they were both the same, I assume they are designed like this?

 

Cheers

 

Dave

Edited January 24, 2009 by Dave_McC

[Rom 0]

Ive not reangled my manifold, but you want the joint as straight as possible really. The gasket on the downpipe breaks up easy if there on too much of an angle.

They will take up some mis alignment, but anything too serious could cause problems sealing.

 

I think your right about the longer bolts. Think the other set is too short to even start threading ? Or is it the other way round and the long ones dont clamp when done up...i cant remember

Youll need tools to do the nuts up, they shouldnt be too hard to do though.

[welshpug 1,666]

when I trial assembled the nuts onto the bolts, they threaded on easily until the last thread of the nut started to engage on the thread of the bolt - and then they got really tight and needed spanners to continue. As they were both the same, I assume they are designed like this?

 

yes, they are locking nuts

[Baz 421]

yes, they are locking nuts

 

Ovalised ones.

[Cameron 16]

Next time, instead of cutting the flange off just cut a length out of the straight section and then weld it back up. That way you're guaranteed to keep the correct angle.

[Miles 331 1 Cars]

I never use those nut's as they are a pain to remove, Allways a open Stainless nut work's and in the years I;ve used them not one has fallen off.

[Dave_McC 0]

Thanks all.

 

Cameron, the problem is I'm using a QEP reangle plate - so I'm guessing the angle of the manifold flange will be different to where the original 8v flange sat.

 

The snag with welding the downpipe flange on at an angle is that the downpipe inside it is then offset at an angle, which won't be great for gasflow - but would be better for getting a good seal to the manifold. It looks like it needs to sit at about 10 degrees off square.

 

Dave

[Cameron 16]

Well it's true that It won't be absolutely ideal but with the power output of an mi you wouldn't even notice. I'd be more worried about using a reangling plate to be honest.