Z3 1.9i Exhaust Query

[Alan Patterson]

Hi Folks. I am in the process of over wintering my Z3 1.9 M43 Motor. Did the sills, welder up the sill fronts behind the plastic liners, replaced rattling DISA, fixed oil filter housing leak and replaced gearbox and diff oils as well as a full service. Running great and then I hear an exhaust blow!!

The car comes with piles of receipts but no where can I see an exhaust, so I assuming that its the original. Its a 2000 car with the M43 unit, 129k miles.

The blow is coming from the pint ahead of the Cat where the two manifold pipes merge into one. It seems to be covered by a stainless shroud that clamps onto the pipes. The blow is at the point where the single pipe exits the shroud. The rest of the system is still gas tight although looks a little rusty in places. I have stuck a bit of gun gum in the leak - although can hardly see it. Will try running the engine in a day or two to see how its holding (if at all!)

My question is

A. Is this a common place for it to go?
B. Can they be repaired - the metal looks sound enough
C. Where is a good place to but replacement exhausts. Looking on ebay tied me in knots. Scared to call BMW. Stainless any good?

Any advice greatly received.

Cheers

Alan

 

[Nodzed]

What do you mean "welded up the sill fronts behind the plastic liners"

 

[Alan Patterson]

Thank you. At the rear of the front wheel arch where allthe crud builds up there was perforation about 3/4 inch square. Cleaned up and welded in patches. Coated in zinc and then 2 pack epoxy chassis paint. Tidied up the sill cover leading edge rust proofed and repainted. Looks like the plastic liners had never been out.

 

[Sean d]

Thank you. At the rear of the front wheel arch where allthe crud builds up there was perforation about 3/4 inch square. Cleaned up and welded in patches. Coated in zinc and then 2 pack epoxy chassis paint. Tidied up the sill cover leading edge rust proofed and repainted. Looks like the plastic liners had never been out.

Very common place for the inner sill ends to go. I'm sure you could weld the exhaust

 

[colb]

Considering all the work you have put in on the car so far, what about considering a custom built stainless steel system fom one of the stainless exhaust specialists. If the car is a keeper then worth doing to finish the job off and no further exhaust worries for the future.

 

[Stevo7682]

Hi I have an m43 and m44 z3 the m44 came with a 2 piece exhaust but unfortunately the factory m43 exhaust is a 1 piece.
Aftermarket system ( even genuine bmw) comes as 2 parts
Front pipe / Cat
Centre/ rear silencer

 

[Synclare]

Think you'll find the majority of the original exhaust is stainless steel. Worth having it welded. As an aside is your support strap between exhaust and gearbox intact? If not the flexing between exhaust and engine/gearbox unit can lead to fractures. Check the support strap is there and intact.

 

[IainP]

Hi Folks. I am in the process of over wintering my Z3 1.9 M43 Motor. Did the sills, welder up the sill fronts behind the plastic liners, replaced rattling DISA, fixed oil filter housing leak and replaced gearbox and diff oils as well as a full service. Running great and then I hear an exhaust blow!!

The car comes with piles of receipts but no where can I see an exhaust, so I assuming that its the original. Its a 2000 car with the M43 unit, 129k miles.

The blow is coming from the pint ahead of the Cat where the two manifold pipes merge into one. It seems to be covered by a stainless shroud that clamps onto the pipes. The blow is at the point where the single pipe exits the shroud. The rest of the system is still gas tight although looks a little rusty in places. I have stuck a bit of gun gum in the leak - although can hardly see it. Will try running the engine in a day or two to see how its holding (if at all!)

My question is

A. Is this a common place for it to go?
B. Can they be repaired - the metal looks sound enough
C. Where is a good place to but replacement exhausts. Looking on ebay tied me in knots. Scared to call BMW. Stainless any good?

Any advice greatly received.

Cheers

Alan

Buy a reel of stainless off ebay, about 8quid for one of the little reels, will work OK with argoshield if aluminised, should really be argon if fully stainless, though it will work.
If the shroud is in the way best thing is to cut it off. I always try to do it in such a way as to bolt it back on, even if it means welding on a tab or two.
Take the exhaust off if you can, very much easier.
Clean up wherever it's cracked with a flap disc or scotchbrite type wheel.
Pulse weld all the way round parallel to the cracks, close as you can whilst on decent metal, both sides. Then weld onto the edge of your weld both sides until you bridge the gap. Will last for years.
Do Not weld into the cracks directly! Not only will you go straight through but the carbon will cause massive sparking and spatter. Not nice if you happen to be trying to fix in on the car and are under it the time.

Iain

 

[Alan Patterson]

Thanks for the replies. I was having a better look at the whole system last night and none of it is looking too cute, the middle silencer is starting to disintegrate and the system looks like its one complete piece. I have decided to bite the bullet and go for a whole aftermarket system. I thought it would be worth paying a few extra quid to go for an original BMW system. Called my local parts department, and although I knew it would be pricier, I was stunned at the price. Front system with Cat - firstly no stock showing in UK or Germany, but they are on back order. How long for - unknown, so no delivery date can be given. Price to you sir, £1500 inc VAT!! That is only the front piece!! Back section is a far more "reasonable" £600 inc VAT - bargain! So "only" £2100 for a whole original system! So worth more than the whole car then!! I think I would want to get the exhaust insured separately!!

I'll drop the old system, and see where I am with it. The mount near the "Y" is still there but rusted through slightly - still supporting but probably allowing some movement. Will investigate replacing this. Hope the lambda sensors come out OK - they look well rusted in!

On a separate note, any good suggestions for decent "budget" tyres. I am not a fast driver and normally go for Toyo/Uniroyal type stuff. Its got 225/50 R16 on the back. I was hoping for £70 or less each bought and fit them locally.

 

[colb]

Re tyres, I don't spend a fortune as the car is summer use mostly and not too much of a speed merchant these days, stick to the limits these days. I always have a look at Black Circles web site and now Motor KIKI to see what is available at local fitters.
Always worth cross checking prices with the actual fitters web site if they have one just to get the best deal.
https://www.blackcircles.com/
https://www.motokiki.com/

As to exhaust, get a quote from one of the stainless system manufacturers for a custom job, got to be cheaper than BMW.
http://www.profusioncustoms.com/bmw-z3-stainless-steel-exhaust/

Bound to be someone near to where you live who makes systems and fits them if you don't want to travel far.
Local to me is http://www.longlifecaerphilly.co.uk/
Other members on here have used them.

 

[Olliebeak]

My exhaust is also a one piece job and was blowing around the seam of the centre resonator. I wanted to keep the original front pipe with cat as I have heard the aftermarket ones are rubbish and the car would not pass the emissions test at mot.
I cut the front pipe with an angle grinder just in front of the resonator and bought a new rear exhaust from Germany off ebay , only around £45 good quality really heavy . I had to cut off the joining flange and clamped the two sections together. There is only around 10mm to get the clamp on so I may get a short length of pipe welded on so the sleeve clamp has a better hold.
Total cost only around £48.

 

[Stevo7682]

My exhaust is also a one piece job and was blowing around the seam of the centre resonator. I wanted to keep the original front pipe with cat as I have heard the aftermarket ones are rubbish and the car would not pass the emissions test at mot.
I cut the front pipe with an angle grinder just in front of the resonator and bought a new rear exhaust from Germany off ebay , only around £45 good quality really heavy . I had to cut off the joining flange and clamped the two sections together. There is only around 10mm to get the clamp on so I may get a short length of pipe welded on so the sleeve clamp has a better hold.
Total cost only around £48.

So if it had a flange unit did you buy an m44 rear section then graft it onto your m43 system.

 

[Olliebeak]

The M43 and M44 appear to be the same , they were not listed as different units. Because I had to cut the front section just in front of the middle silencer there was no flange to bolt the rear section onto. I then had to cut the flange off the rear section and use a sleeve clamp to bolt the two sections together.
It would probably have been more straight forward two buy a new front pipe at around £75 but I wanted to keep the original BMW cat on the front pipe.

 

[JCN]

Thanks for the replies. I was having a better look at the whole system last night and none of it is looking too cute, the middle silencer is starting to disintegrate and the system looks like its one complete piece. I have decided to bite the bullet and go for a whole aftermarket system. I thought it would be worth paying a few extra quid to go for an original BMW system. Called my local parts department, and although I knew it would be pricier, I was stunned at the price. Front system with Cat - firstly no stock showing in UK or Germany, but they are on back order. How long for - unknown, so no delivery date can be given. Price to you sir, £1500 inc VAT!! That is only the front piece!! Back section is a far more "reasonable" £600 inc VAT - bargain! So "only" £2100 for a whole original system! So worth more than the whole car then!! I think I would want to get the exhaust insured separately!!

I'll drop the old system, and see where I am with it. The mount near the "Y" is still there but rusted through slightly - still supporting but probably allowing some movement. Will investigate replacing this. Hope the lambda sensors come out OK - they look well rusted in!

On a separate note, any good suggestions for decent "budget" tyres. I am not a fast driver and normally go for Toyo/Uniroyal type stuff. Its got 225/50 R16 on the back. I was hoping for £70 or less each bought and fit them locally.

Hi Alan,
In my role as complete novice, I just bought a 2001 1.9i and my local MotoSave fitted me a new front exhaust plus Cat for about £290.

Much quieter now

 

[Stevo7682]

The M43 and M44 appear to be the same , they were not listed as different units. Because I had to cut the front section just in front of the middle silencer there was no flange to bolt the rear section onto. I then had to cut the flange off the rear section and use a sleeve clamp to bolt the two sections together.
It would probably have been more straight forward two buy a new front pipe at around £75 but I wanted to keep the original BMW cat on the front pipe.

They are different. ( the rear essentially the same bar the flange)

The m44 came from factory in 2 parts
The m43 came as 1 part
The front section of the 2 engine is completely different.
The aftermarket rear section for m44 will have a flange ready to bolt to front pipe/cat whereas the m43 aftermarket rear section ( or genuine bmw) has to have original exhaust cut and sleeved to join both

 

[Alan Patterson]

Well, removed the exhaust. Bloody hell they are heavy! Removed stainless shroud and there is an almost 300 degree crack all the way round. Looks like it is a stress fracture. The nearby support was badly corroded. And allowing movement. Did try some welding and blew holes. Planning on taking it to local blacksmith fabricators to weld a patch collar .

 

[Ianmc]

In my role as complete novice, I just bought a 2001 1.9i and my local MotoSave fitted me a new front exhaust plus Cat for about £290.

My hard-won experience is that aftermarket cats do not work on the M44 engined car. It is likely that your 2001 1.9 is a M43 so might be OK - did they do an emissions check after the cat was replaced?

 

[JCN]

My hard-won experience is that aftermarket cats do not work on the M44 engined car. It is likely that your 2001 1.9 is a M43 so might be OK - did they do an emissions check after the cat was replaced?

Oooh. I didn't realise there was that kind of complexity.

Thanks for the update... I guess I'll find next month when I take it for its MOT

 

[JCN]

Oooh. I didn't realise there was that kind of complexity.

Thanks for the update... I guess I'll find next month when I take it for its MOT

According to my VIN-check thingy I have an M43TU, so fingers crossed

 

[Alan Patterson]

Mines definitely a M43 unit. Its currently sorned until better weather and while I am doing the work on it .MOT due mid April so it will be interesting to see how it does on the new after market German exhaust I have ordered. I have the emmision results from last year. Toying with the idea of getting its original exhaust repaired by a local smithy/fabricator as a back up.