Definitely a defective piston.

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Very informative! Great video.

 

Great content! The theory on what happened on cylinder 2 and correlation to IAT was interesting too.

 

Great analysis


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What timing for me! Im one of the people who have had an over rev failure recently but haven’t come forward yet. Exactly as Speedy stated, I thought I would be blamed as my tuner is well respected here and I wasn’t really up to defend myself.

My failure though was the SC! It got smoked into a hundred pieces. Pics are in my gallery if anyone is interested.

I had a bunch of runs where I was hitting 7,100 rpm on the shifts as Speedy said, though my tuner said he was commanding them to shift at 6,400. I very naively assumed he would fix it or it must be okay or whatever. SC exploded at the track during testing for a P1620 code.

I’ll be in the shop next week having it looked at and getting it fixed.

Speedy is really a great asset to this Forum. Brought me out of the dark and feeling alone.

 

What timing for me! Im one of the people who have had an over rev failure recently but haven’t come forward yet. Exactly as Speedy stated, I thought I would be blamed as my tuner is well respected here and I wasn’t really up to defend myself.

My failure though was the SC! It got smoked into a hundred pieces. Pics are in my gallery if anyone is interested.

I had a bunch of runs where I was hitting 7,100 rpm on the shifts as Speedy said, though my tuner said he was commanding them to shift at 6,400. I very naively assumed he would fix it or it must be okay or whatever. SC exploded at the track during testing for a P1620 code.

I’ll be in the shop next week having it looked at and getting it fixed.

Speedy is really a great asset to this Forum. Brought me out of the dark and feeling alone.

PM sent lol I think

 

Hey Speedy - Awesome Videos and love your analysis. I think you are bang on. Funny thing cyl 7 let go in my 1st motor as well. Not the same way, we had a fuel issue but same cylinder. We have since moved on to a custom built 426 with all the goodies. Love your channel, just sub'd. Best of luck on the rebuild.

 

Great video, tnx for sharing the knowledge!

 

Good video. Postmortem on a blown engine is always of some value. Can be difficult though as one is looking at engine after the initial failure. But usually one can determine or make a pretty good guess as to what initially went wrong.

Like others I think defective piston was the cause of the failure. The engine is only as strong as its weakest part and with the extra power and elevated RPM limit you found the weakest part. Chances are had the engine remained stock the piston would have been just fine. As power and RPMs go up the extra load and stress on the engine and its parts is not linear.

The failure suggests that it might be prudent to when modifying an engine over a certain HP limit to fit stronger pistons and rods. Cheaper I think to do this to prevent a failure of a stock piston or rod rather than deal with a blown engine.

BTW, years ago I had a 2 stroke motorcycle and I fitted a high compression head to the engine. On WOT runs the engine would slow down some. What was happening is the high compression head caused the engine and especially the piston to run hotter. The piston swelled up and was starting to bind in the cylinder. Fortunately I backed off the throttle and that the engine had some miles on it probably gave it just the margin it needed for the piston to not seize in the cylnder and result in a fracture of the rod or piston. Might mention too I used a superior 2 stroke engine oil, a caster bean based oil (the exhaust had an amazing odor from this oil) and that probably helped the piston avoid seizure in the cylinder.

 

Looks like when I get tuned, 6500rpm is max for my shift points. Ill even be ok with earlier shift points on the 1-2 and 2-3 just to be on the safe side. Thanks for the video Speedy, good luck with your Redeye engine

 

Modifying anything is always a gamble . Better parts just lessen the gamble . I once had a very high dollar engine ( the only one I ever had someone else build) let go with very little use on it . A bad wrist pin caused the problem we found out..... Guess what no warranty.... No warranty on race parts remember .

If you wanna play be prepared to pay ........

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This was a very informative video. My best guess is you had a piston failure.. In the mast production of anything there can be quaility escapement. Most manufactures add a certain amount of risk to their production efforts because of this known anomally.

Great job and keep up the good work. I'm moving on to a Red Eye but my Lizzy will stay in the garage and I'll keep following you.

 

I have nothing more to add or offer on the subject. This is a sh*t happens situation. I really appreciated the video and tear down, and yeah... that red block and black valve covered engine was a pretty good hint about what coming next. Looking forward to seeing it.

 

I have nothing more to add or offer on the subject. This is a sh*t happens situation. I really appreciated the video and tear down, and yeah... that red block and black valve covered engine was a pretty good hint about what coming next. Looking forward to seeing it.

I noticed that too!

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Have seen a 5.7 piston brake in this way. In this instance it was caused by multiple rod failures.

 

In the beginning of the video you showed the block. It didn't look like the #7 bore had any rod thrashing marks in it. That's very unusual for a piston failure. Usually if the piston pulls apart, the whole rod thrashes around in the block for a few cycles. The small end of the rod and the pin many times will break through the block into the water jacket and then all Hell breaks loose. When there is a clean bore (no marks) it is usually the big end of the rod that failed (as in a bolt or something similar). The rest of the rod beam and still assembled small end, pin and piston then work their way down the bore just enough for the flailing crank big end to knock it into the lower side of the bore. Then something gets wedged in or breaks. The piston and rod start migrating down the bore until the rest of the rod fails due to contact.
What's odd about your failure is your piston was high up in the bore. I've seen them get knocked back up the bore some, but usually if they get hit that hard the aluminum can't take it and you get piston shrapnel.
But . . . any better video of the bore and especially that connecting rod? What did you find of the rod big end and bolts? What did the piston pin look like?

 

In the beginning of the video you showed the block. It didn't look like the #7 bore had any rod thrashing marks in it. That's very unusual for a piston failure. Usually if the piston pulls apart, the whole rod thrashes around in the block for a few cycles. The small end of the rod and the pin many times will break through the block into the water jacket and then all Hell breaks loose. When there is a clean bore (no marks) it is usually the big end of the rod that failed (as in a bolt or something similar). The rest of the rod beam and still assembled small end, pin and piston then work their way down the bore just enough for the flailing crank big end to knock it into the lower side of the bore. Then something gets wedged in or breaks. The piston and rod start migrating down the bore until the rest of the rod fails due to contact.
What's odd about your failure is your piston was high up in the bore. I've seen them get knocked back up the bore some, but usually if they get hit that hard the aluminum can't take it and you get piston shrapnel.
But . . . any better video of the bore and especially that connecting rod? What did you find of the rod big end and bolts? What did the piston pin look like?

Anyone know how to multi quote on the new software??

@TrackDay this is what was most surprising to me. I expected to find a hole in the block and beat up cylinder walls, but as you saw, I probably could run a hone in cyl 7 and put a new piston in. Crank might have needed some cleanup but overall it wasn't bad considering.

I think I showed me rotating the big end around the crank, it was still attached, moved smoothly, and the cap bolts were A OK. I never found the rod, so it either shot out the hole in the oil pan with the wrist pin, or ended up in the oil pan (we didn't pull it). I found the wrist pin on the ground about 10 feed behind the car. It looked like a clean 19mm socket, no torn up spots, bends, etc. Must be super tough.

When mine broke it sounded like a high power rifle. Real high pitch "PEEOWWW" sound. So the wrist pin exited the motor with A LOT of force. Never heard any clanking or banging from the motor after as I pulled to the side of the track. Just smoke out the back.

 

Great video Speedy! Really informative stuff. It’s weird that #2 melted both straps on the spark plugs. I know you said in your video that the IATs got to 248 because of a possible fire but you’d think the temp would have been spread across all cylinders. Strange. Can’t wait to see the next video.

 

Great video Speedy! Really informative stuff. It’s weird that #2 melted both straps on the spark plugs. I know you said in your video that the IATs got to 248 because of a possible fire but you’d think the temp would have been spread across all cylinders. Strange. Can’t wait to see the next video.

I’d guess , if you looked at the valve timing of those two pistons, #7 started coming apart, lost all compression and #2 was sucking in the raw fuel sitting at the top that cylinder for the more then a few rotations before total #7 failure.


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I've never understood why some criticize others when they post about failures they've had in their motor or any other driveline part. It primarily seems to happen to lesser known members. Once one criticizes, the gang mentality takes over and others start to pile on. It just seems so childish to me when I see it. Unless someone does a deep dive like @Speedy did here we never really know all of the factors that contributed to a failure. Kudos to Speedy, and I hope people learn to be more positive and inquisitive rather than critical in future situations. It helps the Forum community.

 

Great video, Speedy. Now I understand why a double feature was ruled out; that was a detailed video with a lot of content. Thanks for walking us through the tear down and diagnosis. Very informative!

Paul...

 

Now I know something is wrong when knock sensor catch nothing while there is still knock going on.

 

Those folks who have been offering up a similar thing happening to them: has there been any common rhyme or reason? Year model? Anything?

 

Not really. Most were modded, only a couple were stock. Some had hit rev limiters a couple times, others did not report that. Some happened under hard acceleration, and some in ECO mode easing down the road.

 

Great video Speedy thankyou really makes you think, seeing this may be just what I needed to see for deciding build, I believe it will be worth the wait to go with doing internal build before doing pulley swap, etc,
Can’t wait to see the final results, good luck Speedy

 

J,
Reading another another thread made me think about something, which you may have already discussed.
When you raced at anytime did you go WOT and you were below 1/2 Tank of gas?
I'm sure you know but if daily driving and racing I have found that keeping the tank at 1/2 full is best to do.
If you go below with a hard launch like in racing it can throw the gas to the back of thank and cause air to be sucked in. This is a horrible engine feeling. Something that we learned on the 1st time racing after AJ loaded in the 1st Tune to start the Diablo Tuning and R&D for our Hellcats (then continued with Josh. )
My engine was not hurt and I am still running the same engine that came with my Hellcat.

There have been several engines blown from E85 users as E85 does get used up quicker.

Prior to the Hellcats in our SRT8s we ran 1/2 tank for weight savings. NEVER can we do this with a Hellcat.

Linda

 

J,
Reading another another thread made me think about something, which you may have already discussed.
When you raced at anytime did you go WOT and you were below 1/2 Tank of gas?
I'm sure you know but if daily driving and racing I have found that keeping the tank at 1/2 full is best to do.
If you go below with a hard launch like in racing it can throw the gas to the back of thank and cause air to be sucked in. This is a horrible engine feeling. Something that we learned on the 1st time racing after AJ loaded in the 1st Tune to start the Diablo Tuning and R&D for our Hellcats (then continued with Josh. )
My engine was not hurt and I am still running the same engine that came with my Hellcat.

There have been several engines blown from E85 users as E85 does get used up quicker.

Prior to the Hellcats in our SRT8s we ran 1/2 tank for weight savings. NEVER can we do this with a Hellcat.

Linda

I've always tried to keep mine right at 1/2 tank, but last year at VMP it did go below (we made 25 or something passes LOL). The car slowed down on my last pass and I couldn't figure out why. It was almost 2/10 off. When I reviewed data logs we saw the bypass opened and bled off boost (car was stock at that time). The only thing I could figure is it detected low fuel. If memory serves the needle was in between 1/4 and 1/2 when that happened.

 

OK Good.

 

Remember "Family Cruzin"? His car broke a piston/rod under light acceleration. I believe some pistons just aren't as strong and over time they fail. So it may have broken in Eco mode, but the damage could have started long before the actual failure. Kinda stinks since there isn't much warning, at least for me. AJ says he could see it in the dyno sheet I posted and the dyno was ran months before the failure, but unless you've seen thousands of dyno graphs like he has I don't think you'd be able to tell. The dyno sheet looked normal to me and the car ran great at the track the weekend before it failed running 10.1s at 134ish MPH.

 

Being able to pick that up from the dynograph is pretty amazing.

 

@Speedy, who's red block engine do we see early in the video in the background. Was that on purpose?

Great video and info, thanks! Hope I never experience it. I hate to screw with it too much besides a bit of optimizing because of the absolute torturous right foot of mine for 15-20 minute road course sessions.