A member here suggested I post the pictures of this manifold for opinions on the welding. I currently have this manifold on my car but it's cracked in multiple places. The manufacturer has replaced it and this is the new one. I'm not a welder so I'm not sure if the welds are good or not so this is why I reached out to him.

I have also spoken to my tuner and received his opinion but browsing through this Forum I see there are a lot of very qualified welders so I'm hoping to get opinions so I can make an educated decision on what I'm going to do.

I've taken a lot of pictures, sorry they are a little crappy I can't find my wife's camera so I took them with my cellphone, so I'm just posting a link to the album on my PhotoBucket account. I appreciate your input.

http://s968.photobucket.com/user/Tea...ies%20manifold

 

While I've seen worse, there are quite a few spots that undoubtedly are not fully penetrated and this manifold has not been back purged either. If I had to guess, looks like they are not chamfering the pipe enough to get quality penetration.

Where did your old manifold crack at? Certain locations?

 

Here's some pictures of the cracks. The first cracks I noticed were around where the runners meet the flange. Then I noticed it's cracked completely around where the tubes meet on one of the runners.

http://s968.photobucket.com/user/Tea...ies%20manifold

I'm going to look it up but what does "chamfering" mean?

 

Ive been welding, professionally, for over 25years, and am also a certified welding inspector. That weld would have been rejected by any inspector I have every worked with.

It was either not purged at all, or had poor purge. Weld prep was not good. You can tell that by how narrow the bead is on the outside. It simply isn't possible to have had a good bevel on it and it be that narrow at the top.

This is an example of somebody learning to weld from people that make manifolds. They try to mimic a look on the outside of the pipe, but have no real training or skill, when it comes to making a sound weld.

Here's the problem that causes welds like this to crack:
As the metal heats up, it expands. Since there was no fusion at the root, those areas will heat up faster than the rest of the pipe, including the outer areas of the weld. These areas where there is no fusion or penetration are like thin areas and that's why they heat up faster. As they heat, they expand...at a faster rate than the outer layer of weld. Being that they are touching each other, the area inside expanding faster than the outside, it stresses the weld and eventually can crack it.

Many manifold makers will quickly replace a manifold, so they don't damage their reputation. Some of them may make some welds that look uniform on the outside, but very few will actually be getting a weld that would pass on most pipe welding jobs.

 

I looked it up. So it's basically beveling the edges on all the straight cuts correct?

 

So in your opinion what are the chances of these welds cracking again?

 

lot of manifolds seen with no even back purge and selling for crazy money

 

Yeesh, that is bad. Just going to back up (not that he needs it) what Engloid is saying here. This manifold is probably just going to crack again and again.

 

My opinion, it's a matter of time. Will it be while you still own the car? after you sell? Will the car outlast it? Perhaps. There's no way of knowing ahead of time. Most don't ever crack, because they are removed, car goes to crusher, etc...before they fail, but it doesnt mean the weld was done right, just that it didn't get used enough to crack.

 

to get zero penetration like that without purging would be mean the weld is wayyy shallow. if it was back purged poorly to get the color on the inside, the one penetrated weld isn't candied so that would be my guess, then maybe its deep enough to survive, which it sounds like it isnt.

I'd way rather see a weld thats 90% penetrated than one thats clearly overheated. corrosion and precipitation have way more to do with failures than penetration as long as you're even halfway close to doing it right Imo.

To be fair, as lame as it is to the "craftsman" welders, non purged manifolds will survive with a relatively low failure rate. and a lot of the big name high volume companies don't purge still.

It really sucks when you choose to put the time in to acknowledge that the failure rates on what we'd consider garbage are still reasonable to most companies.

 

Without doing some type of testing, there's no real way to know how much penetration was achieved. It could be 99% penetrated, yet you not be able to see it from the inside. That said, based on my experience, I would highly doubt this particular weld got even 75% penetration. Looks way cold.

candied? never heard that term. I know what you mean, based on context, but it is usualled "sugared." Are you perhaps in another country, or perhaps it's a regional term?

That's something that can be debated, but not really able to be proven on either side. I would think that carbide precipitation would take many years to have a failure...but the right mount of stresses, cused by lack of fusion (no penetration), could cause a failure on even the first heat cycle. IMO, you shouldn't have to choose between penetration or carbide precipitation. The amount of money many of these places charge, they should give better quality. I think that many of these builders simply dont know how to give better quality, so they make excuses as to why it's good enough, low failure rates, etc.

Not doubting you on this...but can you tell me more...what companies, pictures, etc? For one, I'm curious as to whether they actually admit not purging.

The rates are higher than you may suspect. Many failures are not posted on the internet. Some builders actually stop building because they have to continually replace manifolds to keep failure talk off the internet.

For those that don't know or aren't sure what proper root penetration should look like on purged stainless, I attached a picture. Is it the prettiest? No...but it is 100% acceptable. It's hard to get a picture on the inside of a piece of pipe.

 

a one off manifold, if the time is taken to build it properly, would cost upwards of $2k. most people just aren't willing to pay that, so you get this as a result.

in my experience, the most common failures are the wg branch and the head flange. the hf should be welded on the inside if there is not full penetration. the wg flange should go directly on the collector if at all possible, and the dump tube needs to be supported at the end. the highest temps will be seen in the collector so fatigue from heat cycles will be magnified in all those welds.

aaron

 

Good info

 

welding is joining metals together. does that pipe look like its joined to the other pipe with a weld. not really. that weld is just a surface weld and a waste of good stainless pipe. it may last but its not a proper weld.

 

The head flange to runner welds are pretty thin. looks like the same amperage as the pipe.

needs to get ready for a hot paw and turn the welder up to something higher like 130Amps instead of 60.