What a 0 mi factory piston looks like.

[McRat]

Remember GM has that bulletin about "star pattern" on the piston indicates you were running tuning? This a piston from an engine that was test run at Moran, but damaged during shipping to the assy plant. I bought the engine at auction, it's a LiLLY:

 

[sweetdiesel]

Whats Moran?
Whats Damaged on the engine?

Does this mean GMs bulletin was full of the #2?

 

[McRat]

Moran Ohio? is where they build the Dmax engines. Nothing is wrong with the engine, I was tearing it apart to build it up.

 

[McRat]

To anyone looking for a spare LiLLY engine, there is one in the neighborhood for $5500 complete 50k mi. PM me if interested.

 

[1FastMax]

Is there a faint touch of valve contact also, or is that just me?

 

[JoshH]

Moran Ohio? is where they build the Dmax engines. Nothing is wrong with the engine, I was tearing it apart to build it up.

Moraine, OH.

Anyway, so is that the star pattern they were talking about? Do you think maybe they had the power turned up on it to see what kind of damage and accelerated wear it would show, or is that what anyone should expect to see when tearing into a stock engine?

 

[Flashscan]

$5500 complete 50k mi.

Yeah 50k mi, but a 1/4mile at a time :rofl:
That's a pretty good price, about the same as the cheap ones on Ebay but, at least you can trust Pat (or you know where he lives!)

Cheers,
Ross

 

[turbo-max]

looks to me that is just the spray pattern from the squirters

 

[Mike]

Remember GM has that bulletin about "star pattern" on the piston indicates you were running tuning? This a piston from an engine that was test run at Moran, but damaged during shipping to the assy plant. I bought the engine at auction, it's a LiLLY:

That's not a star. Too many points. Must have been something else. LOL Just Kidding..... Thanks for the picture

 

[McRat]

The used LLY is from BMS Machine, not me. Just posting it for them.

No, the new engine I pulled the piston from was just test run like all Dmaxes. There was no oil in the intake tract or carbon on the exhaust. Looked brand new everywhere except the piston crowns and chambers had light carbon that could be wiped off with your fingers.

If you map out the injector spray pattern vs timing vs piston shape, you will see the injector sprays the top of the piston with stock tuning.

 

[SmokeShow]

Any explanation for this? pilot injection causing it?


C-ya

 

[MaxFarmer]

I havnt seen many duramaxes apart, but all the ones I have seen have all had the pattern on them. I just figured it was normal.....

 

[dieselson]

Is there a faint touch of valve contact also, or is that just me?

I don't think that is just you

 

[zfuller123]

so really this just means that GM is trying to make up reasons to not warranty their stuff, even for those who aren't doing anything? That's kinda bogus...

 

[McRat]

Yes, GM is playing games. Factory tuning sprays the piston just like aftermarket does.