M20 exhaust manifold gasket questions

[xavier]

Does the m20 motor in 323i have one gasket per cylinder exhaust port, or is it one big gasket that includes all 6 outlets? Do I take the heat shield off before loosening the exhaust manifold bolts? I cannot find a good link on replacing the gasket between the exhaust ports on the head and the exhaust manifold. Anyone know a good site?

[pacerpete]

All E30 M20 engines IIRC ,use two gaskets that come with integral heat shields , IE each gasket does three cylinders . It is a pretty straight forward but tedious job. The drama starts if / when the studs start snapping when you try and undo the 30 year old 12mm nuts

The usual advice involves dousing all twelve nuts (and the downpipe to manifold nuts) with a penetrant of choice. Leave for a period of time then start the car, get it hot and then try and undo as many nuts as you can . The back two manifold ones are usually the most likely to already be MIA or to snap when you attempt to undo them. These are the two that are the most awkward but also the two that the whole job hinges on so it is worth getting slightly warm if the nuts undo.
Once you have loosened most / all of the nuts, let it cool down then more penetrant and Bobs your uncle

Don't worry if any of the studs unwind with the nut, it is when they snap the worrying starts

[Gavla]

So what is the solution if they snap off...

[pacerpete]

So what is the solution if they snap off...

Drill out the remainder , BUT due to access issues , head removal is often the only answer

[Speedtouch]

Or MIG-weld a nut onto what's left of the stud, assuming enough remains - the heat will help crack it loose.

[pacerpete]

Or MIG-weld a nut onto what's left of the stud, assuming enough remains - the heat will help crack it loose.

Indeed and that method gets most removed when you have a 'stump' to play with .
Alas, when M20 studs snap, it is in 99% of instances flush with the head That is why it is so important to make an effort to save them .

[xavier]

The odd thing is all the gaskets are fine except for the one nearest the fire wall. It isn't there at all(fallen out?). All the other ports from the head have gaskets but not the last one. Also the last two studs had no nuts on them for some reason. These two studs are in good condition and not broken. I was able to spin two new nuts on easily. Where did the gasket go if it is meant to be attached to the others? All a bit odd . I will order some new gaskets and pull it all off at the weekend. Thanks for the advice on the penetrating oil.

[pacerpete]

If the nuts had not been fitted or were loose, the exhaust gases would have over time literally blown the gasket out.

[xavier]

I took a look at the heat shield today. On mine the heat shield seems to be one long unit, not two. Is this because my car is so old(1984)? I suppose the two part heat shield should fit.

[pacerpete]

I took a look at the heat shield today. On mine the heat shield seems to be one long unit, not two. Is this because my car is so old(1984)? I suppose the two part heat shield should fit.

I can only recall the gaskets that do three ports each with an integral heatshield. I doub t if the Aussie turds are any different. What does RealOEM list ?

[Brianmoooore]

This is shown for Australia: http://2009.bmwfans.info/parts/catalog/ ... n_control/

In the wrong forum too!

[xavier]

Lawdy lawdy! so mine has a separate heat shield. Can I use the integral gasket heat shield gaskets on my old motor I wonder?

[pacerpete]

Lawdy lawdy! so mine has a separate heat shield. Can I use the integral gasket heat shield gaskets on my old motor I wonder?

Lets have a pic of your turds manifold etc. I didn't think Aussie cars had full on septic style emissions crap until '86 ? Have you got a cat as well ?

[xavier]

no emissions rubbish on my old 323i. I will try to get a photo on Sunday

[Brianmoooore]

Stuff in my link was only fitted in Australia, Sweden and Switzerland. That doesn't mean all cars in these countries had it, and if you don't, then you have the same three port + integrated heat shield gasket that the rest of us have.

[xavier]

Here is the Photo of the heat shield. Yep it looks a one piece. I will take it off and get the individual gaskets for the 6 ports.
Thanks folks
http://i583.photobucket.com/albums/ss27 ... 1390789592