Cracked exhaust manifold; KG 10v turbo engine

Sabre75 · 21-11-12, 07:12 PM

Evening folks,

It seems using the term 'crack-on' about my project has come back to haunt me; I took the inlet manifold off my KG engine last night and discovered a crack through the manifold at the cylinder #4 outlet

KG exhaust manifold - top view - crack at cylinder #4

KG exhaust manifold - bottom view - crack at cylinder #4

(the yellow duck-tape is to stop anything taking up residence in my cylinders btw!)

After reading thought Phil Payne's page on the 10v turbo exhaust manifold [http://www.isham-research.co.uk/quattro/urquattro_manifold.html] I found out it's likely due to a collapsed engine mount in it's previous fitment. Oh well ...

So my question (finally!) is what's the best solution for the problem? From Phil's page it seems welding the manifold might not work too well? That said if anyone's had theirs welded up with no problems I'd be interested to know, as well as any recommendations for who'd be able to do the job well. I'm in the Salisbury-Shaftesbury area so anyone nearby? - somehow I don't think I'll give it a try with my little MIG welder!

If welding isn't an option can anyone suggest an alternative? I think the £375 Dialynx manifold is probably out but anything else? Does anyone have a 10v turbo manifold spare? (with an nice uprated turbo perhaps?!!

)

Any help much appreciated,
Cheers,
Tom

(right, off to refit the Avant's front shock in the rain ...

)

missfire · 21-11-12, 08:35 PM

Holy grail, if you can find a Dyalinx manifold, buy it.

I've two welded manifolds here, wouldn't put one back on I don't think. The welding on the one that was on my car is way better than the welding on the welded one I bought, and that one (with the good quality welding) was cracked when I took it off, right through the weld. Welding might hold up better with new engine mounts, don't really know, but I doubt it.

Sabre75 · 21-11-12, 08:52 PM

Quote:

Originally Posted by missfire

Holy grail, if you can find a Dyalinx manifold, buy it.

I've two welded manifolds here, wouldn't put one back on I don't think. The welding on the one that was on my car is way better than the welding on the welded one I bought, and that one (with the good quality welding) was cracked when I took it off, right through the weld. Welding might hold up better with new engine mounts, don't really know, but I doubt it.

Hmmm, that was pretty-much what I thought ... *sigh*

I might give myself a laugh and see how much TorqueTechnics want to build me a custom manifold & downpipe to mate to the exhaust on the Coupe; that'll be reasonable, right ...!

missfire · 21-11-12, 10:55 PM

Much visited subject this, especially be me. If you've got a grand to spend, go for it.

There can be only one, and it's a Dialynx! (not a dyalinx.. like I said in the first post, they're rubbish..)

Timbo · 22-11-12, 08:30 AM

I have a Dialynx on my 86 WR and TBH I wouldn't rush out and buy one, mine is blowing, It isn't cracked and has been checked, thought it might just be a gasket, but have been informed that they warp and now might be faced with getting mine skimmed. Mine was already on the car when I got it, but I would change mine for a SS at the drop of a hat if I was going to have to pay out. I will keep mine on, even if it does need skimming, becasue hopefully that will be the cure mine needs for a few more years happy motoring.

missfire · 22-11-12, 11:08 AM

Dunno man, everyone seems to have their own experiences of them. If you see one fitted with brand new VAG studs, nuts and washer I can't see any way the thing will shift, no matter how it's heated, no way, you could hang a bus off of mine.

I thought mine was warped, looking along the ports, so took it to be skimmed and it wasn't warped! It was just the big gap between port two and three that made it look like port three was sitting proud of the rest. It had been on a WR for seven years with the wastegate screwed down hard, so it's had a fair old baking over the years! It still has the original machining marks on the mounting faces so hasn't been skimmed yet. There must have been a bad batch that warped or something.

Here's my theory - Mechanic or non-mechanic removes old nuts - one or two bind - stress the stud - and just before the stud shears it comes out of the head with the nut. - Mechanic or non-mechanic then refits the manifold using the same studs - expansion takes place - weak studs pop, or fall out. Just a theory mind!

mikes2 · 22-11-12, 11:10 AM

They always go at that place. They also crack at the collector and the casting above and below the collector can also go.

I had mine welded earlier this year and it's back on the car. Done about 1000 miles since it was refitted. So far so good

Sabre75 · 22-11-12, 08:14 PM

From what I've read/heard there doesn't seem to be a 'best solution' to this one; different people have had different experiences

What I'll probably do for now, to keep the project rolling and to keep the cost down (or at least offset it for a while!) is to try the welding option. I've spoken to the guys who orignally built the exhaust for my Coupe and they're going to take a look and see what they can do; I figure if anyone's going to be able to repair a manifold it's an exhaust specialist!

I'll keep you posted about how it all goes ... unless a mint-condition manifold falls into my lap in the meantime!

saladdodger · 22-11-12, 08:27 PM

Mines blowing, until I take it off I wont know if its cracked or just the gasket.

I was wondering if I buy some stainless tube I can recreationte it myself by wrapping the manifold in the tube and welding it piece by piece.

missfire · 22-11-12, 09:20 PM

Quote:

Originally Posted by Sabre75

I figure if anyone's going to be able to repair a manifold it's an exhaust specialist!

You need a welding specialist not an exhaust specialist!

On the one I took off the welding has been done properly, it's well 'stuck', the weld is well and truly part of the manifold, but it must have mounted again into the car with done-in engine mounts (if that's the cause) as the original line of the crack just came straight through the weld.

My engine mounts were goosed! I cut the offside engine mount in half with a hacksaw to see what's inside them, answer - not helish much if it's been baked by a turbo for 20 years! Nothing 'hydro' about that one I can tell you.

You can see the remains of whatever fluids were in it, a kind of toffee looking varnish was all that was left.

I'll put a thread up showing the different layers of the mount sometime, but I reckon in the bottom of the mount it looks like there's a kind of diaphragm with a vent to atmosphere (the wee holes in the bottom/alloy shell bit of the mount). I reckon the fluid gets out when this bursts maybe. Silly bloody design whatever, why not just make them out of solid rubber?!

22-11-12, 11:10 AM	#7
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	They always go at that place. They also crack at the collector and the casting above and below the collector can also go. I had mine welded earlier this year and it's back on the car. Done about 1000 miles since it was refitted. So far so good __________________ 1991 90 quattro 20v sport 1991 90 quattro

21-11-12, 08:35 PM	#2
missfire making wooden things Classic Audi Club Member Join Date: Dec 2009 Location: cow land Posts: 8,156	Holy grail, if you can find a Dyalinx manifold, buy it. I've two welded manifolds here, wouldn't put one back on I don't think. The welding on the one that was on my car is way better than the welding on the welded one I bought, and that one (with the good quality welding) was cracked when I took it off, right through the weld. Welding might hold up better with new engine mounts, don't really know, but I doubt it.

21-11-12, 10:55 PM	#4
missfire making wooden things Classic Audi Club Member Join Date: Dec 2009 Location: cow land Posts: 8,156	Much visited subject this, especially be me. If you've got a grand to spend, go for it. There can be only one, and it's a Dialynx! (not a dyalinx.. like I said in the first post, they're rubbish..)

22-11-12, 08:30 AM	#5
Timbo Grown up member Join Date: Feb 2008 Posts: 74	I have a Dialynx on my 86 WR and TBH I wouldn't rush out and buy one, mine is blowing, It isn't cracked and has been checked, thought it might just be a gasket, but have been informed that they warp and now might be faced with getting mine skimmed. Mine was already on the car when I got it, but I would change mine for a SS at the drop of a hat if I was going to have to pay out. I will keep mine on, even if it does need skimming, becasue hopefully that will be the cure mine needs for a few more years happy motoring.

22-11-12, 11:08 AM	#6
missfire making wooden things Classic Audi Club Member Join Date: Dec 2009 Location: cow land Posts: 8,156	Dunno man, everyone seems to have their own experiences of them. If you see one fitted with brand new VAG studs, nuts and washer I can't see any way the thing will shift, no matter how it's heated, no way, you could hang a bus off of mine. I thought mine was warped, looking along the ports, so took it to be skimmed and it wasn't warped! It was just the big gap between port two and three that made it look like port three was sitting proud of the rest. It had been on a WR for seven years with the wastegate screwed down hard, so it's had a fair old baking over the years! It still has the original machining marks on the mounting faces so hasn't been skimmed yet. There must have been a bad batch that warped or something. Here's my theory - Mechanic or non-mechanic removes old nuts - one or two bind - stress the stud - and just before the stud shears it comes out of the head with the nut. - Mechanic or non-mechanic then refits the manifold using the same studs - expansion takes place - weak studs pop, or fall out. Just a theory mind!

22-11-12, 08:14 PM	#8
Sabre75 Grown up member Classic Audi Club Member Join Date: Feb 2012 Location: East Knoyle, nr. Salisbury Posts: 134	From what I've read/heard there doesn't seem to be a 'best solution' to this one; different people have had different experiences What I'll probably do for now, to keep the project rolling and to keep the cost down (or at least offset it for a while!) is to try the welding option. I've spoken to the guys who orignally built the exhaust for my Coupe and they're going to take a look and see what they can do; I figure if anyone's going to be able to repair a manifold it's an exhaust specialist! I'll keep you posted about how it all goes ... unless a mint-condition manifold falls into my lap in the meantime!

22-11-12, 08:27 PM	#9
saladdodger Senior Member Classic Audi Club Member Join Date: Jun 2011 Posts: 1,030	Mines blowing, until I take it off I wont know if its cracked or just the gasket. I was wondering if I buy some stainless tube I can recreationte it myself by wrapping the manifold in the tube and welding it piece by piece.