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Discussion Starter · #22 · (Edited)
Like 3 miles on the 131 kit. It never left the shop, I wouldnt have made it home if it did. And the MoCo wanted screenshots of the ECM tuning screen looking for any reason they could find to deny the claim.

So, it was a manufacturing defect. I believe the cylinder tolerances was too tight after talking with the mech. I believe everything was done properly on his end after I interviewed him.

Both cylinders had scoring, back was not as prominent as the front but still had obvious scoring, no burn marks on the spigot was mentioned like the front cylinder had.

I am hoping the crank runout on the new bottom end is better than the original which had .004". Just squeaked by on what S&S calls allowable for their billet cam plate, oil pump, or gear drive cams which is .005". They used to say .003" was max allowable, but have recently changed that spec. I would like to see the new bottom end meet the old S&S standard, and most M8 cranks are within .005, the MoCo's spec is .010" or less.
 

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Like 3 miles on the 131 kit.
Damn - that whole thing sucks. I’m sure you were really looking forward to getting it back. Guess if there’s a silver lining it’s that they did the work and they’re making it good for you. Bad news - another crawl through 500 mile break-in/oil service.
 

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Discussion Starter · #24 ·
Well, I would have had to do the 500 mike break in anyway. I was hoping to be able to do that before eureka springs, but now that will be impossible.
 
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Discussion Starter · #29 ·
They did not determine the cause, but it looks like to me that the cylinders were under size to cause that huge burn discoloration in 3 - 4 miles!

Cylinders being too small would also cause insufficient oil lubrication of the cylinders as well.

If the cylinders and pistons were scored without the black coating being rubbed off severely and over heating marks, then yeah, I'd say mechanic error. But the MoCo didn't even send out an inspector which would be normal procedure when something like this happens, so I think the MoCo knows there is a problem and authorized complete motor replacement over the phone.
 

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What beat up the top of that piston?
 
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I don't think that's the top of the piston, looks like they set the cylinder on the benchtop, notice there's no cutaways for the valves.
That's it Kyle! Thanks.
 
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That's it Kyle! Thanks.
Hey, when I first saw those pictures, I thought the exact same thing until I looked closer, so when you asked, I knew exactly what you thought you saw, because I thought the exact same at first.
 

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I wonder why there wasn't a feeler gauge check for piston to wall clearance before assembly, would have save a lot of heartache!
 
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As short lived at that was, it looks like poor preparation during pre-assembly, that is signs of dirt in the cylinder or on the piston that didn't get properly cleaned, those vertical streaks look like something was broaching the cylinder wall. those 2 oval spots about a 1/3 of the way down the cylinder look like a distortion created tight spot. That motor would need the cases split and everything cleaned and all bearings and seals replaced before being used again. Hopefully they will save you time by replacing the whole engine. What does the combustion chamber look like? Does it show signs of metal bouncing around?
 
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