welding cast manifold???

[Monkeymagic]

my wife had a new motor months ago and i set about getting her old tt ready to sell. one thing that was obvious was an exhaust blow. i suspected the manifold had cracked.
i finally got round to removing it today and its cracked externally where 1 of the 3 bolts passes through to the turbo.
I looked and the k04 manifold seems hard to get and is bloody silly money from audi.
I have ordered a second hand one but was really tempted to grind a groove and weld it up.
Has anyone tried this and did it work??? Steven

[mac2226]

Yes It can be done,there a crap design and don't last long best of getting a cheap second hand 1 with no cracks and put that on instead. I know your selling the car but that's what I would do

[ManiacuV6]

You can weld it but firstly you need to heat up the manifold till is red and in that moment you start welding.

[driftin jo]

You can weld it but firstly you need to heat up the manifold till is red and in that moment you start welding.

This^^^ and use inconel filler rod.

[Monkeymagic]

well I've ordered a second hand one 50 quid delivered.
i hope it is crack free as advertised.
unfortunately the tt has to go as the wife went all sensible and got a car which is good on fuel!

[Error404]

As above you need to heat it first. I know a guy in Willenhall that will repair it for you if needed Steven

[adam g]

The quote I got for a welding an RS2 manifold the proper method, i.e glowing red first came to almost the cost of a new manifold once I had added the cost of the second hand one to work on. The guy said some machining was required because the heat distortion meant refacing the flanges also.

[popdemonic]

I believe it can be done with the specialist.All cast manifolds does that.You need to grind down the crack lines in the V shape to allow heat expansion and
increase the welding space between the cracks.Heat up the cast until it's growing read and start welding it with welding cast steel.

[diesel des]

I high nickel rod can be used no problem. Can be done at normal temperature, but should pean as cools.

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[chezz]

Why is Brazing not possible? Capillary force combined with flux, draws it into small sized cracks.

[driftin jo]

Why is Brazing not possible? Capillary force combined with flux, draws it into small sized cracks.

Manifold in use on turbo car ~600 deg c.
Typical melting point of braze ~450 deg c.

[Monkeymagic]

there is some distortion on the mating face. i have also noticed there is a crack running internally between the ports where they go from 4 into 2.
i suspect the cost to repair would be too great.
i just hope the second hand one is mint.
if we were keeping the car id look at a performance one but when done Im only asking 4k for a quick sale.
which for a low mile car with full black leather bose etc is really good condition is cheap.

[AndyP]

Anybody got a cracked cast manifold they don't want? I want to have a go at welding one cold with some Nickel rods I've got.

[driftin jo]

Anybody got a cracked cast manifold they don't want? I want to have a go at welding one cold with some Nickel rods I've got.

Don't bother welding it cold as this will stress the hell out of it and it is likely to crack
near to were you just welded when it cools down at the next weak point due to the stress.

Heat it up first, you don't need to get it very hot to ovoid stressing it when welding
it unless you are going to do a huge weld.

Getting it to 240 deg c from a domestic oven will make it much more likely to be a success than welding it from cold.

If you want to do the best job you can at home also heat up some sand in the oven and bury it in the hot sand when you have welded it, let it cool down completely then shot blast it if you can.

[Monkeymagic]

I've got a cracked one you can have or else its going on my scrap pile!