MPE post-crack repair: More or less likely to crack again?

[-BEASTMW-]

I'm having the hardest time finding an MPE v2 and am wondering if a v1 will suffice. I plan to keep this car for many years as my DD, so longevity is important.

I know the majority of v1s haven't cracked, but cracking isn't exactly uncommon. Assuming it cracks at some point and is repaired well, does the fact it has cracked and been repaired make it more likely to crack again? I fear once it starts, it might continue getting worse, to the point where it's barely salvageable. Or conversely, once the cracked weak spots have been welded, does that effectively make it stronger than before in the vulnerable areas?

[Mvy]

A welded area will always be weaker than it was before the repair.

[UPSROD]

Drilling holes at the end of each crack will help stop the crack, but any weld will be more brittle than the original mettle and tend to crack again over time. I think as long as you have a welder available I would do the re-enforcement with the tubing running through the cans like the V-2 exhaust has.

[nycplumber]

Originally Posted by Mvy

A welded area will always be weaker than it was before the repair.

Not exactly true. The HAZ, Heat affected zone will become weaker on strengthened steel but the weld itself will be significantly stronger than the previous metal its replacing. In this application I do not believe, based on design that it will be more likely to crack. I think it will be much less likely. Based on the fact I've never heard of welding an mpe twice

[nycplumber]

Before this thread gets derailed by some serious misinformation I suggest people reading this and commenting to research welding a little more. Welds are the strongest part of any metal to metal connection.

https://www.google.com/amp/s/amp.red...nger_than_the/

[Hierlevelz]

Originally Posted by nycplumber

Not exactly true. The HAZ, Heat affected zone will become weaker on strengthened steel but the weld itself will be significantly stronger than the previous metal its replacing. In this application I do not believe, based on design that it will be more likely to crack. I think it will be much less likely. Based on the fact I've never heard of welding an mpe twice

Thank you for addressing the misinformation. I'm amazed how many people think they're a subject matter expert.

[Mvy]

Im not a chemist or a scientist with a background in metallurgy, but I do have some real life experience with getting things welded and seeing them break again in the same area. I'm sure I am not the only one. There are a lot of factors that come together (no pun intended) when welding, and one should consider the expertise of the welder, the material they choose to fashion the repair etc.

If your intention was to discredit my response by posting a reddit blog, you are in fact spreading more mis-information and not responding to what my answer was. I never said the weld is not stronger. I said the WELDED AREA is weaker. Assuming you buy the people posting on reddit as "subject matter experts" then read what they wrote (from your link) :"So while the weld itself may be stronger, the material surrounding the weld can infact now become the weak point of the material, since it has become annealed and lost a lot of it's strength." Basically, if there is an underlying weakness causing you to need the repair, sometimes welding makes the item weaker and more likely to crack again. Your response is the same thing I said "The HAZ, Heat affected zone will become weaker on strengthened steel." This is my experience, take it for what you will.

[///M Power-Belgium]

Originally Posted by -BEASTMW-

I'm having the hardest time finding an MPE v2 and am wondering if a v1 will suffice. I plan to keep this car for many years as my DD, so longevity is important.

I know the majority of v1s haven't cracked, but cracking isn't exactly uncommon. Assuming it cracks at some point and is repaired well, does the fact it has cracked and been repaired make it more likely to crack again? I fear once it starts, it might continue getting worse, to the point where it's barely salvageable. Or conversely, once the cracked weak spots have been welded, does that effectively make it stronger than before in the vulnerable areas?

Keep in mind weld repairs on Inconel requires a specialist !
Advice : You should go for a MPE 2 only .

Crack repair on a MPE 1 .

[vincE92M3]

If you look into an MPE thread I created, you'll find that there is a trend where MPE v1 produced/ sold prior to a certain date do not seem as susceptible to cracking. Almost as if there was a bad batch of v1.

[UPSROD]

Originally Posted by vincE92M3

If you look into an MPE thread I created, you'll find that there is a trend where MPE v1 produced/ sold prior to a certain date do not seem as susceptible to cracking. Almost as if there was a bad batch of v1.

I totally agree!