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Exhaust manifold repair??
richard thomas - 17/12/06 at 07:43 PM

Hi all,

Can anyone recommend a place to have my stainless manifold repaired? It seems to be very thin walled material ( it's a westfield megabusa one ). I got home this afternoon and heard a bit of a blow - on investigation it has a 5mm hole in the inside bend of the No.2 primary pipe...it looks quite hard to get to. The manifold is only a couple of years old, I got it second hand. I thought that stainless were meant to last for years?

Rich.


TimC - 17/12/06 at 08:44 PM

U have U2U


ChrisGamlin - 17/12/06 at 10:58 PM

Although stainless won't rust, it cracks more easily than mild steel, and if the crack is around the collector area on the inside of a tube like you suggest, then it may be very tricky if not impossible to re-weld properly without cutting it into pieces again


02GF74 - 18/12/06 at 09:44 AM

quote:
Originally posted by richard thomas

I thought that stainless were meant to last for years?




you thunk wrong, all it means is more corrosion resistant, given the right condtions, it will rust. Stainless is a bad materail for exhausts as it is brittle and not a good conductor of heat.


richard thomas - 18/12/06 at 04:13 PM

Thanks guys,

I think it is cracked due to stress or something, it doesn't appear to be corroded.

I think to repair it i'll have to cut the offending primary off,repair it and reweld it back on again - or just get a pattern primay pipe made and weld that in. The thing is it seems so thin walled i might have bother finding something similar... it always sounded a bit thin - like a ticking sound from the pipes when idling.I know it's only low mileage though - Chris, it's the one i bought from Baz Busa. I might ring w*stfield to see if it's common although i am pretty sure it'll be the first time they've heard of it.....

What's the cost of having a a bespoke manifold made? a replacement from w*stfield is £310...

Rich

[Edited on 18/12/06 by richard thomas]


ChrisGamlin - 19/12/06 at 07:05 PM

Hi Rich

To get it welded up properly you'll probably need to chop off the intermediate pipe that joins the two primaries, then get the primary welded back onto the collector from the inside, then weld the intermediate pipe back on again.

To get a new well designed / made custom made manifold is probably going to cost you more than £310, mine cost nearer £600 although was made by the chap that also makes manifolds for World Superbikes and is a bit of a work of art (unlike the rest of the car )

Also getting a single replacement primary pipe made up will still cost a fair bit as the primaries are what takes the most amount of time to bend and get to the right length etc, so I'd look at getting the current one repaired if I were you.

It also might be worth looking at how your silencer is supported because it may be putting excessive stress on the manifold if not supported properly, which will cause it to prematurely crack.


tks - 19/12/06 at 07:36 PM

can you make a pic..

i Would just fill it up with a stainless mig..

also what is thin??
Thin isn't very normal to bend sow i guess you have 1,5mm and thats fine to weld.

to stop de sound you maybe even can weld from the inside..or just fill up everything sow the air cant escape.etc..

saying thats its true it would be the last thing i would do.

maybe you can insert a small pipe 1mm thickness or something...

Tks


richard thomas - 19/12/06 at 08:37 PM

Hi all,

I will try to get a pic on tomorrow...

I am afraid to get it filled with weld as the pipe will have weld material intruding into the gas flow and cause turbulence/restriction.

I spoke to longlife exhausts in Cardiff today, they said to bring it in and they will have a gander at it with a view to repair - it's got to be worth a go. At the very worst i'll have to get another from Westfield - at least it's guaranteed to fit!! This car seems to be a money pit

I did think that it might be under stress but i've had another check and it seems ok...I wonder whether a stone has been flung from the tyre onto the pipe and created a stress point??

Still not sure what the thickness is but it seems to be less than 1.5mm - i'll have a measure tomorrow and report back.

Rich.


Peteff - 20/12/06 at 12:02 AM

So what, all the work's been done before it gets that far. Don't worry about it robbing you of .005hp, the exhaust probably wasn't 100% efficient in the first place. Edit:- it's not going to gas you in an open top car, ignore it anyway if it's not deafening you.

[Edited on 20/12/06 by Peteff]


Volvorsport - 20/12/06 at 12:26 AM

if you need somebody to tig it up - i know a man who can .

he does bike engines .


richard thomas - 21/12/06 at 09:06 PM

Thanks guys,

I've had it tig'd by longlife in Cardiff, nice job by all accounts and all for a tenner too!

I mentioned the weld protruding into the exhaust purely because if i welded it with my mig i'm sure there would have been a lot....

Anyway, as it happens when i took the manifold off and had a better look at it there was another hole directly opposite in No. 3 primary. First thoughts were 'b*ll*cks!' but looking at it it seems there was a weld between the two to keep the pipes in the correct place. The weld has detatched and left two holes behind.

I'll post some pics tomorrow...

Rich.


TimC - 21/12/06 at 09:14 PM

quote:
Originally posted by richard thomas
I've had it tig'd by longlife in Cardiff, nice job by all accounts and all for a tenner too!



Result! I thought they'd do a decent job!


richard thomas - 22/12/06 at 04:18 PM

Some piccies.....
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richard thomas - 22/12/06 at 04:21 PM

Another...
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richard thomas - 22/12/06 at 04:24 PM

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Description


richard thomas - 22/12/06 at 04:26 PM

Job done - £10......luvverly!!
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G.Man - 22/12/06 at 05:00 PM

hate to be a doom merchant, but i think vibration will fracture that again...


richard thomas - 22/12/06 at 07:31 PM

Unfortunately, i think you are right.....

Do for now though!

Sideways at Christmas!!!!

Rich.


ChrisGamlin - 22/12/06 at 08:39 PM

I was assuming the manifold had cracked but hose holes look more like either wear holes where the two primaries have fretted together, or almost as if the combination of two pipes next to each other and the heat wrap have made a hot spot and its melted!

I would probably remove the exhaust wrap so its just around the first part of each primary as it comes through the bodywork, then at least you can keep an eye on it over time.


907 - 22/12/06 at 09:50 PM

Hi Rich

Your exhaust pipes, you don't know what they are made of by any chance?

If they are 409 s/s then this is just 11% chrome steel, no nickel.

This has to be welded with 309 (25 / 20) filler wire. This is the stuff that people on this forum tend to refer to as "dissimilar rod".

Myself, I tend to use 309 on any stainless that I don't know the grade of, just to be on the safe side.

I hope I'm barking up the wrong tree, if not, this may be of help.


Paul G


richard thomas - 24/12/06 at 02:19 AM

Thanks guys,

Not sure of the material, just stainless...

The edge of the holes looked like a tear/crack type of thing. I think there was a weld between the two which has pulled and left the holes - the pipes are close but they won't actually touch each other.

Rich.