LB7: Autopsy Reveals

[S Phinney]

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Well I pulled the engine and started the teardown today. I found the expected cracked piston. I also found a couple of cracks in the Y bridge.

 

[gmduramax]

Did any other pistons start to crack?

 

[blk smoke lb7]

Did it hurt the cylinder?

 

[S Phinney]

Did any other pistons start to crack?

All the others look fine. No visible problems.

Did it hurt the cylinder?

The cylinder should clean up just fine. I plan to go to .040 over from the .020. There was minimal issue at the top. Looks kinda like aluminum slag.

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[x MadMAX DIESEL]

Was that a custom welded y bridge? If so I don't think it's cracked, rather just the weld. We're those major Motorsport pistons? What kinda power did it crack? Injector hang open on it or just broke one day??

 

[arneson]

I believe he was just over 1000hp. Cant remember forsure what he said.

 

[OregonDMAX]

it looks to me like the weld itself cracked, you can see where the weld was smoothed out inside and the crack formed in the weld bead

 

[MaxPowerLB7]

Sorry to see the piston damage. Is the y bridge cracked on the outside too? Looks to me like it's the seam where the pipes meet.

 

[x MadMAX DIESEL]

1000 horse only that scares me!! I hoped these pistons would handle more than that

 

[Harbin_22]

1000 horse only that scares me!! I hoped these pistons would handle more than that

Only 1000hp :roflmao:

 

[x MadMAX DIESEL]

Well the stock cut lb7 pistons have done that

 

[S Phinney]

Was that a custom welded y bridge? If so I don't think it's cracked, rather just the weld. We're those major Motorsport pistons? What kinda power did it crack? Injector hang open on it or just broke one day??

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The bridge is definitely cracked. The line generates from the weld and is cracked in the weld on the other side. Trent did it. I don't think the metal thickness can handle the stress. I had one of Tonys bridges crack before. It did not see this much boost. Those where Mahle motorsports race cast. It broke suddenly. It makes triple digits.

 

[quinton]

Man that sucks. I hope I don't have any problems with fingers pistons. Yours looks just like mine but mine was stock piston.

Here is the set I'm getting. You should try them unless you where gonna go forged.

 

[S Phinney]

I am going forged. Maybe that will prevent cracked pistons.

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[x MadMAX DIESEL]

You've cracked multiple haven't you? What brand are you getting Ross, arias? I've started to regret my piston choice myself now that I don't drive it daily, and I'm only in the 700s. Only reason I got the cast was I had planned to dd mine between seasons but I don't think I will anymore.

 

[S Phinney]

I have cracked a cut stock piston. It was in the 700'then. I went with the forged Arias. I could not turn down the cost compared to everyone else. I will also be getting one that will work with the Brodix heads as well. They require a different valve relief than current designs. Not that I will every use them with that head but I will at least have it.

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