(Partially solved, DOD delete is completed) Need help. DOD delete went south…

[thefrey]

Took my heads off to find my #4 piston ready to leave this world.

No idea what to do now. Pan is already off so I could swap the single piston.

Tuner said he’s surprised it ran as well as it did.

Any help appreciated. Thanks in advance.

 

[thefrey]

Update: pulled the piston out… and wow.

 

[Bigburb3500]

Update: pulled the piston out… and wow.

View attachment 473861

That’s not ready to leave this world… that’s left and on its 12th life…

 

[thefrey]

 

[SpareParts]

Wonder what caused it?
You ordering a new piston?

 

[thefrey]

Wonder what caused it?
You ordering a new piston?

No idea what caused it. Going to inspect the head and pull the valve to see if it was something with that. I wonder AFM had something to do with it with cylinder deactivation, and unburnt fuel.

The valve that is a different color is piston #4 (aka new paperweight)

Plan is to either put a new piston or find a used piston to put in there. Sourcing another piston seems to be a slight challenge because I think the GM replacement is 0.5MM oversized.

On the bright side… the cylinder walls look good and the cam and rod bearing of #4 checked out well

 

[swathdiver]

Wonder what caused it?

No idea what caused it.

I know what caused it. Low octane fuel. The previous owner(s) ran that thing on 87 and this is what happens over time, all the time.

Only a fool runs 87 in a high compression performance LS engine.

 

[thefrey]

I know what caused it. Low octane fuel. The previous owner(s) ran that thing on 87 and this is what happens over time, all the time.

Only a fool runs 87 in a high compression performance LS engine.

I would agree on the fuel side, but none of the other pistons show wear like that… if this is truly a fuel knock issue then why wouldn’t all of the pistons be exhibiting other issues?

 

[SpareParts]

Here ya go.
Sorry. that was a 5.3

 

[thefrey]

Here ya go.

Pardon Our Interruption...

Thank ya. I should have mentioned I need one basically tomorrow or Tuesday.

 

[Dustin Jackson]

@thefrey If the cylinder walls look fine I'd probably try to slap a new piston in there and run it. Everything else looks good from what I'm seeing

 

[thefrey]

@thefrey If the cylinder walls look fine I'd probably try to slap a new piston in there and run it. Everything else looks good from what I'm seeing

Yep. I appreciate it. This is the route I’m taking. I am already this deep so I might as well finish it.

I am slightly worried that the other pistons could be compromised but that maybe shouldn’t be a concern.

Finding a replacement piston that is standard size is proving to be a challenge, surprisingly. Finding used is hard too, but going to call around tomorrow as an option.

I ordered from what I understand is a true GM OEM replacement, but it says it doesn’t fit on some websites. My guess is because GM may call for oversized pistons for replacing?

The cylinder walls feel good and there are no grooves or anything that I can feel with my bare hands. This pic shows the cylinder where the cracked piece was and the exposed area.

 

[Dustin Jackson]

@thefrey As long as the compression test is good you should be ok. Should be able to find a piston there are enough of those motors out there

 

[SpareParts]

Please. Once you get it, weigh it for me. I really need that info!

 

[thefrey]

Please. Once you get it, weigh it for me. I really need that info!

Will do! I ordered a GM 19208471. It is a stock standard size replacement for the 6.2. Are you planning on using the same piston at some point?

 

[SpareParts]

No. I need the weight to compare against my new .020 over silver o lite pistons

 

[swathdiver]

I would agree on the fuel side, but none of the other pistons show wear like that… if this is truly a fuel knock issue then why wouldn’t all of the pistons be exhibiting other issues?

Not necessarily. There may be some correlation as to which pistons fail first but I never delved into that aspect of it.

Just FYI, Melling makes replacement pistons and even cylinder liners and a whole bunch of other parts for these engines.

 

[thefrey]

Not necessarily. There may be some correlation as to which pistons fail first but I never delved into that aspect of it.

Just FYI, Melling makes replacement pistons and even cylinder liners and a whole bunch of other parts for these engines.

I think the issue was most likely a collapsed AFM lifter that dumped a bunch of fuel from the valve in at once and had detonation rather than a fuel quality issue but I am not sure 100%

 

[swathdiver]

I think the issue was most likely a collapsed AFM lifter that dumped a bunch of fuel from the valve in at once and had detonation rather than a fuel quality issue but I am not sure 100%

That doesn't make sense to me. What I am sure of is that this is relatively common with 6.2s and busted pistons in them is a sign of prolonged use of low octane fuel. All across social media will you find evidence of this.

 

[thefrey]

That doesn't make sense to me. What I am sure of is that this is relatively common with 6.2s and busted pistons in them is a sign of prolonged use of low octane fuel. All across social media will you find evidence of this.

No idea. Do you know how common this is in general?

I’ve been running e85 recently especially to help clean so I can only assume it was something AFM or gas related