Different exhaust pipe bores for 325?

[Adammcf]

I ordered a new exhaust manifold and downpipe gasket last week.
Today I picked the downpipe gasket up as Im still waiting on the other one to arrive.
Went to fit it and after spending ages getting the old nuts off the damn thing doesnt fit! Its about 10mm too short and the exhaust bores are about 4mm smaller at least each compared to the one thats on the car.

Are there different exhausts for the 325? The owner handbook says my car is a 325 Alpina Conversion, could this be the cause - my exhaust may be larger diameter than a standard 325?

Gonna have to call BMW again on monday morning and see if I can order the correct size.

See the pics here -

[jmc330i]

I had the same problem with mine.

The $tealers said the smaller one was the correct one for my 1991 325i but no way was it going to fit.
In the end they ordered both and I took the manifold to them and picked the one that fitted - the larger one, but they still didnt think it was right.

I think they said the larger one was for a 320i??

Im not sure but I think there is a different bore size between early and late models but the $tealers ETK didnt show it.

My local specialist told me it was definitely the larger one I needed.

[Adammcf]

Very strange. Im not looking forward trying to explain it over the phone if the person on the other end hasnt got a clue.

[Brianmoooore]

I posted a few weeks ago, saying that the exhaust systems of 320 and 325 tourings were identical.
I now know this is untrue, as yesterday I tried to fit the rear section from a 320 onto the front section of a 325 on my M50 engined touring.
The pipe of the 320 rear section which slides over the stub pipe out of the 325 front box was a couple of mm too small.
Don't know if this is of any relavance to your problem, but it confirms that the two are different.

[Adammcf]

Cool. Its strange though as Ive a 325 Sport and the guy ordered the 325 part. Oh well. Roll on monday and I'll see what they say.

[Templ8e30]

I have had this problem a few times with my 1990 320i, some of the later 320i's were fitted with the single piece 325i manifold which has slightly larger bores and needs a 325i downpipe gasket.

I spent a long time arguing the toss in the local Euro car prats trying to explain the fact that the 320i gasket they gave me is too small and that I needed the late 325i one, eventually they swapped it and it fitted perfectly.

Just to confuse the issue some 325i's have a 2 piece manifold (3 cylinders into 1 downpipe x2).

Cheers,

Iain T

[A1BMW325iSport]

i had same problem i ordered one and took it back for the larger one.

[Adammcf]

Looks like its a common problem then. You'd think they'd realise by now.

[E30Adam]

When someone else asked a similar question a while back, I said to them "be careful because there are 2 sizes for the 325i manifold gasket" and I was told I was talking bollox. Just goes to show I was right!

Total pain in the ass because the dealers are guaranteed to give you the wrong one.

[Adammcf]

If this one is the wrong size is there a possibility that the main exhaust manifold on order is the wrong size as well?

[E30Adam]

If this one is the wrong size is there a possibility that the main exhaust manifold on order is the wrong size as well?

If you mean the one that goes between the head and the manifold then they should all be the same, it's just the downpipe gasket that differs.

[Simon]

When someone else asked a similar question a while back, I said to them "be careful because there are 2 sizes for the 325i manifold gasket" and I was told I was talking bollards. Just goes to show I was right!

That was the actual manifold that was questioned, and it was me who said they're the same....if you take a look at the etk it shows the manifold with identical part numbers between the 320i/325i. The gaskets are obviously different, and there also seems to be 2 different size gaskets for the 325i, maybe it's a mistake with the BMW etk and theyve got the gasket part numbers mixed up between 320i/325i.

Just for the record I have managed to fit a 325i 2 piece back box onto my 320i front box with no problem.

[Guest]

There are (at least) 2 different exhaust manifolds for 325i, the change occured in Sept '87. They are interchangeable providing you use the corresponding downpipe, the rest of the exhaust is the same.
The major difference is in the spacing of the manifold/downpipe studs and the gasket. There are other minor design differences which I guess was to counteract the warping to which these manifolds were prone.
I speak from first hand experience, it took me a while and several manifolds to work out.

[Brianmoooore]

Simon - I was trying to fit a 320 back box onto a 325 front box. The corresponding 325 back box and 320 front box would fit together and probably tighten up together OK, but the male part of the join would be a couple of mm smaller than the female part.

[Adammcf]

Have the bigger bore part on order now so will find out on sat.

[Simon13]

i've had this Adam same thing, dealer gave me a gasket which was too small for my stainless system. Is it a 3 piece 2piece thing?