Updated engine tear down video

[Rubyred17]

Hello All

I hope I am not starting a war but I am
Really curious about something.

The young lady with the blown GT350 engine posted a video update of her engine disassembly and analysis of the failure. late in the video the failure appears to in one cylinder and it looks like the piston broke (or came apart) and those pieces scared the bore.

My question is if an aftermarket tune that allowed detonation could do that to a piston?

Dan

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[honeybadger]

Hello All

I hope I am not starting a war but I am
Really curious about something.

The young lady with the blown GT350 engine posted a video update of her engine disassembly and analysis of the failure. late in the video the failure appears to in one cylinder and it looks like the piston broke (or came apart) and those pieces scared the bore.

My question is if an aftermarket tune that allowed detonation could do that to a piston?

Dan

Yes...but not likely. A good tune from someone like Shaun at AED or Lund isn't going to cause that. A ringland or oil-related issue likely caused it and had nothing to do with the tune. Proof? I know of many who had the same exact failure on a stock motor.

That said, a super aggressive tune from someone who doesn't know what they're doing could easily do that.

 

[Rubyred17]

Yes...but not likely. A good tune from someone like Shaun at AED or Lund isn't going to cause that. A ringland or oil-related issue likely caused it and had nothing to do with the tune. Proof? I know of many who had the same exact failure on a stock motor.

That said, a super aggressive tune from someone who doesn't know what they're doing could easily do that.

so you are thinking that when the piston is removed the ring or land broke?

 

[honeybadger]

so you are thinking that when the piston is removed the ring or land broke?

A ring land failure is most often related to heat in this engine. If I had to guess, #8 wasn't getting enough lubrication with the oil, friction went up and then melted/weakened the piston enough for it to fail.

 

[Rubyred17]

A ring land failure is most often related to heat in this engine. If I had to guess, #8 wasn't getting enough lubrication with the oil, friction went up and then melted/weakened the piston enough for it to fail.

Great explanation, thank you

 

[DCShelby]

I think she had a Lund tune in it actually. Go check out her youboob channel. She has lots of videos posted for her various mods (the car that is).

 

[thill444]

It seems pretty consistent with other stock motor failures. Personally I think Ford should cover it, but I also get it. When you modify the car and tune it all bets are off when it comes to warranty work related to the motor.

Hopefully she will get the car back up and running soon.

 

[JCSIX13]

looks like she will need a new block or to have that block sleeved.

 

[Hack]

looks like she will need a new block or to have that block sleeved.

Agreed. I wonder if they can do one sleeve, or whether they all have to be done. Either way $$$.

I was thinking the same thing as Honeybadger - too much heat and the ends of the piston ring pushed together and then it broke the ring lands. I don't know why though. Maybe it was low on oil or something? I would be surprised if low oil would do that to just one piston and still leave all the bearings looking ok. I would think the bearings would get hot more quickly than the pistons.

Maybe the tune was trying for too much power and it ran a little lean. It didn't really look like detonation to me, though. Just scratches from chunks of piston bouncing around in there.

 

[Rubyred17]

Agreed. I wonder if they can do one sleeve, or whether they all have to be done. Either way $$$.

I was thinking the same thing as Honeybadger - too much heat and the ends of the piston ring pushed together and then it broke the ring lands. I don't know why though. Maybe it was low on oil or something? I would be surprised if low oil would do that to just one piston and still leave all the bearings looking ok. I would think the bearings would get hot more quickly than the pistons.

Maybe the tune was trying for too much power and it ran a little lean. It didn't really look like detonation to me, though. Just scratches from chunks of piston bouncing around in there.

the other interesting thing was I did not see any scuffing from piston slap

 

[Hack]

I would be surprised if low oil would do that to just one piston and still leave all the bearings looking ok. I would think the bearings would get hot more quickly than the pistons.

I'm odd quoting myself but I just remembered she didn't pull the bottom end apart. Maybe the bearings are trashed and on the edge of failure. That will be interesting to see.

 

[schmeky]

On most modern hi-perf engine failures of #7 and #8 are almost always the ones to let go. They are the last to get the coolant flow, which has been pre-heated by the other cylinders. So these cylinders run hotter and will usually detonate first. There were bits of melted piston in the dome = detonation.

 

[honeybadger]

Fun bit of trivia - the pistons are numbered differently than most think in the Voodoo due to the firing order and FPC.

 

[schmeky]

Honeybadger,

Thanks for setting me straight. I did reference "modern engines, but you are correct nonetheless.

 

[Cobra Jet]

Just curious if anyone has the info:

How does the PCV system work on the Voodoo as far as relationship with the intake and cylinders? Is there a mapping that one can view?

I’m only asking because back in the late 80’s early 90’s, Ford had an issue with the 5.0 Full Size Broncos blowing out cyls 4 & 8 due to the early design of the PCV system and how it was routed via the intake/cylinders. IIRC, this was a common failure point for the 87-90 MYs. Ford rectified the issue with a revised intake and where PCV was located or mapped for the 91-94’s. I have the actual Ford docs stored somewhere - because I owned both an 87 and 94....

I’m curious if such a PCV issue could cause a similar internal failure with the Voodoo?

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