Need opinions on problem. Had a manifold cracked. **UPDATE NEW MANI PICS ADDED**
01-10-2006, 09:21 AM
#63
1.0 BAR
Join Date: Oct 2005
Posts: 216
Re: Need opinions on problem. Had a manifold crack but really strange.
It has nothing to do with flanges.It has alot to do with the levering of the heated stainless steel on whatever its welded or bolted to.We have proof of this is someone will post the results of our little test.
Cracking of stainless steel manifolds probably has more to do with tuning than it has to do with welding.High EGTs put more heat into the manifold and it expands more.
Cracking of stainless steel manifolds probably has more to do with tuning than it has to do with welding.High EGTs put more heat into the manifold and it expands more.
01-10-2006, 09:24 PM
#64
1.0 BAR
Join Date: Jan 2005
Posts: 278
Re: Need opinions on problem. Had a manifold crack but really strange.
Some good points brought up about the absence of carbon, and the idea of cutting the flange between ports. It does appear that it may have been caused by a force on the manifold.
However, in interest of calling it like I see it:
It looks like it was welded VERY hot, which can really weaken the metal. Not only that, but with it being sch10, there's not as much "margin for error." That said, I'm not saying you should have used sch40, only that IF the high heat had something to do with weakening the weld, sch40 may still have had enough strength to have not broken. Not trying to bash anybody's work, and as stated, you said you had improved a lot...but the pice below indicates a lot of heat was used:
Look at the secong runner from the left, the lower weld on it. That looks like you ran a few passes on it without letting it cool down any. Really hot. When you weld multiple passes, it's best to let it cool down and brush off the color before the next pass.
Whether he lifted with the manifold or not, in my opinion, is only important for the purpose of determining what factors combined to create the failure. I think you're doing the right thing by replacing it, as if all things had been right (design, weld, etc), the manifold would have been strong enough to lift the car by. Stainless in these grades has a tensile strength of about 120,000psi if my memory serves me well from the last time I had a test done.
I'm not intending to flame, just state my thoughts and opinions... I think a crack like that would have been easy to hear, and difficult to not hear. However, if cracks like that would prevent the turbo from spooling, we'd all be using 1" pipe for these things.
The idea of it expanding and closing up the cracks when warmed up...I dunno for sure, but I don't see why that wouldn't be possible. I've never run into it or heard of it though.
As for it being dropped...unless it was dropped from a skyscraper, it should have never broken...bent maybe, but not broken.
Again, I think you're doing the right thing by replacing it. In this business, people can be really critical and one crack can sometimes make everybody start thinking all the stuff you do is junk, but that's not really the case. Hopefully people won't be so hard on you for this. It's good to see somebody stand behind their work. It may cost you time and money now, but when people see that you give a ---- about the people that pay for your work, it may bring you a lot more in the future. I'll have to give you two
However, in interest of calling it like I see it:
It looks like it was welded VERY hot, which can really weaken the metal. Not only that, but with it being sch10, there's not as much "margin for error." That said, I'm not saying you should have used sch40, only that IF the high heat had something to do with weakening the weld, sch40 may still have had enough strength to have not broken. Not trying to bash anybody's work, and as stated, you said you had improved a lot...but the pice below indicates a lot of heat was used:
Look at the secong runner from the left, the lower weld on it. That looks like you ran a few passes on it without letting it cool down any. Really hot. When you weld multiple passes, it's best to let it cool down and brush off the color before the next pass.
Whether he lifted with the manifold or not, in my opinion, is only important for the purpose of determining what factors combined to create the failure. I think you're doing the right thing by replacing it, as if all things had been right (design, weld, etc), the manifold would have been strong enough to lift the car by. Stainless in these grades has a tensile strength of about 120,000psi if my memory serves me well from the last time I had a test done.
I'm not intending to flame, just state my thoughts and opinions... I think a crack like that would have been easy to hear, and difficult to not hear. However, if cracks like that would prevent the turbo from spooling, we'd all be using 1" pipe for these things.
The idea of it expanding and closing up the cracks when warmed up...I dunno for sure, but I don't see why that wouldn't be possible. I've never run into it or heard of it though.
As for it being dropped...unless it was dropped from a skyscraper, it should have never broken...bent maybe, but not broken.
Again, I think you're doing the right thing by replacing it. In this business, people can be really critical and one crack can sometimes make everybody start thinking all the stuff you do is junk, but that's not really the case. Hopefully people won't be so hard on you for this. It's good to see somebody stand behind their work. It may cost you time and money now, but when people see that you give a ---- about the people that pay for your work, it may bring you a lot more in the future. I'll have to give you two
01-10-2006, 09:39 PM
#65
0.0 BAR
Thread Starter
Join Date: Mar 2004
Posts: 0
Re: Need opinions on problem. Had a manifold crack but really strange.
Thanks for the insight. I posted the pics knowing full well it may affect how people view what I build. I prefer to know why it happened to correct the issue. I only do this as a hobby so its not like I have to make a living doing it. I was welding way too high amps at that time. I did make multiple passes without it cooling. I know better now and appreciate your views on it.
01-11-2006, 07:16 PM
#66
1.0 BAR
Join Date: Jan 2005
Posts: 278
Re: Need opinions on problem. Had a manifold crack but really strange.
You outta post up some more recent pics, so somebody that hasn't seen your more recent work does know that you have improved.
Hope the hobby/extra spending money effort does you well!!
Welding is something that you can always make some money doing, at nearly any level you want...be it a few hours a month, or a lot.
Hope the hobby/extra spending money effort does you well!!
Welding is something that you can always make some money doing, at nearly any level you want...be it a few hours a month, or a lot.
btw dave. ugh ugh
01-19-2006, 07:21 PM
#68
1.0 BAR
Join Date: Jun 2004
Posts: 271
Re: Need opinions on problem. Had a manifold crack but really strange.
Originally Posted by buk9tp
^^^
exactly.. just an isolated incident..
just a joke. no hard feelings.
:P
exactly.. just an isolated incident..
just a joke. no hard feelings.
:P
01-19-2006, 09:50 PM
#69
3.0 BAR
Join Date: Dec 2002
Posts: 12,568
Re: Need opinions on problem. Had a manifold crack but really strange.
not to beat a dead -----, but dave has the mani now, and there are def some marks around the neck of themani that are fresh and def look like chain action. but who am i to say...... 
