Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Shagma on 11 January 2009, 21:46:03

Title: exhaust manifold welding
Post by: Shagma on 11 January 2009, 21:46:03
As I already have spent too much money on my '97 Omega x20xev I have decided to make a shot on welding the razorthin crack in my exhaust manifold. Replacement parts are really expensive in norway (thanks a lot norwegian taxdepartment!!).

I have some experience from TIG welding, mostly from CUNIAL and stainless steel but also regular steel, not that much from electrodes however I do know how to make a spark ;)
And somewhere along the road I have also tried welding with acetylen/oxygen.

Does anyone knows what kind of welding that is most suitable for welding cast iron, I'd prefer TIG if it is possible?
Title: Re: exhaust manifold welding
Post by: unlucky alf on 11 January 2009, 23:16:34
ive never used a TIG welder so cant comment even though ive had cast alloy welded that way by a company, i have welded cast up with a MIG in the past & has been o,k as a temporary measure, but if its a thick casting then perhaps an arc welder would get better penetration, perhaps somebody on here may have had one done & direct you better, good luck :y
Title: Re: exhaust manifold welding
Post by: shanjon on 11 January 2009, 23:19:41
apparently you need to preheat cast iron before you weld it and as soon as you have welded it you need to wrap it in insulation so that it cools slowly otherwise it will crack if it cools to quickly
Title: Re: exhaust manifold welding
Post by: Andy B on 12 January 2009, 00:54:34
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apparently you need to preheat cast iron before you weld it and as soon as you have welded it you need to wrap it in insulation so that it cools slowly otherwise it will crack if it cools to quickly

Yes. Otherwise you'll probably find a nice crack along side where you've just welded as it cools. A bucket of vermiculite will help it to cool nice & slowly.
IME you need to use MMA (stick welding  ;)) with  a cast iron rod
Title: Re: exhaust manifold welding
Post by: Shagma on 12 January 2009, 20:58:46
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apparently you need to preheat cast iron before you weld it and as soon as you have welded it you need to wrap it in insulation so that it cools slowly otherwise it will crack if it cools to quickly

Yes. Otherwise you'll probably find a nice crack along side where you've just welded as it cools. A bucket of vermiculite will help it to cool nice & slowly.
IME you need to use MMA (stick welding  ;)) with  a cast iron rod
Thanks for the advice.
However, since I do not have any insulation materials available, are there other alternatives..? fluid? heated oil?
Or aluminum foil?  :-/
Title: Re: exhaust manifold welding
Post by: hotel21 on 12 January 2009, 21:32:54
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apparently you need to preheat cast iron before you weld it and as soon as you have welded it you need to wrap it in insulation so that it cools slowly otherwise it will crack if it cools to quickly

Yes. Otherwise you'll probably find a nice crack along side where you've just welded as it cools. A bucket of vermiculite will help it to cool nice & slowly.
IME you need to use MMA (stick welding  ;)) with  a cast iron rod
Thanks for the advice.
However, since I do not have any insulation materials available, are there other alternatives..? fluid? heated oil?
Or aluminum foil?  :-/

Kitchen oven when she's not looking??   ;D :D
Title: Re: exhaust manifold welding
Post by: shanjon on 12 January 2009, 21:38:46
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Quote
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apparently you need to preheat cast iron before you weld it and as soon as you have welded it you need to wrap it in insulation so that it cools slowly otherwise it will crack if it cools to quickly

Yes. Otherwise you'll probably find a nice crack along side where you've just welded as it cools. A bucket of vermiculite will help it to cool nice & slowly.
IME you need to use MMA (stick welding  ;)) with  a cast iron rod
Thanks for the advice.
However, since I do not have any insulation materials available, are there other alternatives..? fluid? heated oil?
Or aluminum foil?  :-/

in theory it may work!!!! do you not have any insulation in your loft you could borrow
Title: Re: exhaust manifold welding
Post by: Marks DTM Calib on 12 January 2009, 21:41:20
Where in Norway are you?

Might be able to bring one over in a few weeks
Title: Re: exhaust manifold welding
Post by: Shagma on 12 January 2009, 22:12:19
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Where in Norway are you?

Might be able to bring one over in a few weeks

I live on the west coast of norway, near Bergen.
You got a working exhaust manifold?
Title: Re: exhaust manifold welding
Post by: Shagma on 12 January 2009, 22:13:45
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Quote
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apparently you need to preheat cast iron before you weld it and as soon as you have welded it you need to wrap it in insulation so that it cools slowly otherwise it will crack if it cools to quickly

Yes. Otherwise you'll probably find a nice crack along side where you've just welded as it cools. A bucket of vermiculite will help it to cool nice & slowly.
IME you need to use MMA (stick welding  ;)) with  a cast iron rod
Thanks for the advice.
However, since I do not have any insulation materials available, are there other alternatives..? fluid? heated oil?
Or aluminum foil?  :-/

in theory it may work!!!! do you not have any insulation in your loft you could borrow

You mean a piece of Glava?
Title: Re: exhaust manifold welding
Post by: Marks DTM Calib on 12 January 2009, 22:15:45
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Quote
Where in Norway are you?

Might be able to bring one over in a few weeks

I live on the west coast of norway, near Bergen.
You got a working exhaust manifold?

Bugger, was in Bergen 2 months ago (used to use a software house there), now only travel to Asker (Oslo)
Title: Re: exhaust manifold welding
Post by: Shagma on 12 January 2009, 22:21:04
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Quote
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Where in Norway are you?

Might be able to bring one over in a few weeks

I live on the west coast of norway, near Bergen.
You got a working exhaust manifold?

Bugger, was in Bergen 2 months ago (used to use a software house there), now only travel to Asker (Oslo)

Ship it from Oslo to my adress, then we'll save £35 in shipping costs..;)
Just kidding, I will make a shot on the welding first..
Title: Re: exhaust manifold welding
Post by: Shagma on 16 January 2009, 16:23:36
I have now removed the manifold.
(http://i397.photobucket.com/albums/pp57/Shagma81/IMG_1230.jpg)
(http://i397.photobucket.com/albums/pp57/Shagma81/IMG_1231.jpg)
The crack has acctually expanded A LOT the last 3 weeks!! :(
(http://i397.photobucket.com/albums/pp57/Shagma81/IMG_1236.jpg)

The thought was to bring to the workshop and first of alle remove the shreded bolt on the bottom flange towards the downpipe.
Then I was thinking of sand blast the whole thing to make it look better, but also to get a better view of the damage.
Now, for the repair.
I was thinking of drilling 3 holes. One on each end of the crack, and one on the center of the crack, tap it M6 and put in a bolt then cut it of flush with the surface.
(http://i397.photobucket.com/albums/pp57/Shagma81/IMG_12391.jpg)
The next step planned was to start welding at the ends.
weld 2 inches at each end.
(http://i397.photobucket.com/albums/pp57/Shagma81/IMG_12392.jpg)
The last step would be to weld the rest of the crack. Can i weld it all in one piece..?
(http://i397.photobucket.com/albums/pp57/Shagma81/IMG_12393.jpg)

Do you guys think this is gonna work ??
Title: Re: exhaust manifold welding
Post by: Andy B on 16 January 2009, 16:36:12
I wouldn't bother with the M6 holes, just get it all nice & hot before you weld it, and then make sure you get an nice even weld on/over the crack. In that position you don't need to prep either ie grind a V into the cracked bit.

A 'new' manifold would be easier though!  :y  :y  :y
Title: Re: exhaust manifold welding
Post by: Shagma on 16 January 2009, 20:34:58
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I wouldn't bother with the M6 holes, just get it all nice & hot before you weld it, and then make sure you get an nice even weld on/over the crack. In that position you don't need to prep either ie grind a V into the cracked bit.


A 'new' manifold would be easier though!  :y  :y  :y

No doubt, but a new car would be even MORE convenient..;)
Nothing but troubles with this piece of junk...

I was thinking of heating the material to approx 60degrees celsius, but is seems like others advice even more.. Perhaps I should go for 100degrees celsius...

You think I can weld it all in one piece or will this make the material drag against the welding point?
Title: Re: exhaust manifold welding
Post by: Andy B on 16 January 2009, 20:38:51
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Quote
I wouldn't bother with the M6 holes, just get it all nice & hot before you weld it, and then make sure you get an nice even weld on/over the crack. In that position you don't need to prep either ie grind a V into the cracked bit.


A 'new' manifold would be easier though!  :y  :y  :y

No doubt, but a new car would be even MORE convenient..;)
Nothing but troubles with this piece of junk...

I was thinking of heating the material to approx 60degrees celsius, but is seems like others advice even more.. Perhaps I should go for 100degrees celsius...

You think I can weld it all in one piece or will this make the material drag against the welding point?

I'd be heating it with oxyacetylene to a dull red!  ;) If not i think you'l find it'll crack along side your weld if you don't get it really really hot.
Title: Re: exhaust manifold welding
Post by: Shagma on 26 February 2009, 21:54:16
thanks.. got i welded by a friend. he told me he had to weld an inch at a time, and hammer the weld flat immediately after welding. otherwise the weld will retract faster than the iron cast material, and cause the material to crack..
the crack was really long, much longer than i expected... but I'm looking forward to check it for tightnes during operation:)
best of all, it only costed me 20pounds...
Title: Re: exhaust manifold welding
Post by: Seth on 26 February 2009, 22:04:43
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apparently you need to preheat cast iron before you weld it and as soon as you have welded it you need to wrap it in insulation so that it cools slowly otherwise it will crack if it cools to quickly
Sounds right this.
But, what about trying fire clay in the split first. Available from plumbers merchants/DIY centres etc. Got to be worth an inexpensive try!