As a Hellcat Owner, I just subscribed to your channel. Your content is much appreciated!!! I look forward to the what's to come this week. Thanks for sharing.
I don't own a Dodge but still love the channel for all the information that is shared. I am always baffled as to why this channel doesn't have a 100k plus subscribers. I watch tons of performance and automotive related channels and yours is one of the best by far.
Excellent input! I had a cylinder 2 fail on mine and found it out from the Buyer of the car as I did not want to rebuild the motor - so I sold it! Blessings for future success!
Exceptional video for all the reasons you stated! I have had 2 engine failures (different platform) - but all of the detail you are sharing here is great along with your and others theories!
I haven't delved far enough in the performance side to have an opinion, but I appreciate the information you've stated here, it'll definitely be useful in the future when I begin engine mods on my R/T. Thanks for taking the time to share it.
Great video! Thanks for sharing the knowledge gained from the failure. I certainly agree with your theory. The point you made previously stands: if you race, you best be prepared for things like this to happen. Thanks again for the way you present your format!
Thanks for the great info. Im thinking of the same upgrades this winter. I differently going ti looking into the pulley(tune), driveshaft, tires, & full exhaust. I just want low 10s. Thanks again bro
The JB Weld piston I ran in my lawnmower did the same thing, tore the piston pin bosses out of the piston after 3 minutes of grass cutting. I have suspected for years that pistons/rods in a 4 stroke engine usually fail when the piston is snapping over TDC between exhaust and intake stroke, as the gas loading on the piston is much less than during compression stroke. Thus the rod/piston would suffer a tension failure at this time versus during the power stroke when the expanding gases would push against the piston counteracting the inertia forces of the piston deccelerating approaching TDC. Just my 2 cents. I also wondered the same thing, as #2 cylinder follows #7 firing in a normal 1,8,4,3,6,5,7, 2 V8 firing order. Forgive me if the Hellcat uses the modified firing order where 7 and 4 are switched.
Speedy you are definitely a racer. Awesome video. I agree with your gut feeling that it was a defective piston. I know you push your engines to the limits with your mods, but you do it by the book. So much to learn from here. Sadly, I don't think it's anything you did wrong, just a defective piston. Thank you.
All I see is too much timing or too much heat in that cylinder. The cylinder got super hot and seized up the piston. That’s why it’s all blue at the bottom. Haven’t built many Hemi’s but I’ve seen this on LS engines where one of the cylinders got too hot. Appreciable you sharing this with us.
I think it'd be hard to get too much timing when it maxed out at 11 degrees, but maybe too little? In the factory tuning timing is retarded in order to heat up the cylinder and light the cats off. Interestingly the factory Red Eye tunes have 9-10 degrees in them max timing.
Yeap a lot of non tuners don't realize you actually can drive EGTS UP with retarded timing as determined by cylinder head design and flame front ( aka 19 degrees is different on an engine that peaks torque at 30 degrees NA Vs say some at 42 on BBC)
Awesome content bud, I have been wondering about my hellcat. I'm making good power and wanting more but it's a daily driven vehicle. I have almost 40k on it now but I did the pulley swap and tune with Petty's Garage. They did a great job with the setup but they left a lot on the table. The swap was done at almost 15k miles, another company said they can get me over 975 from their tune only with what Petty's did. Thanks for your information on what your vehicle did. Keep it up and can't wait to see what happens next. Good luck bro
People most often think about the tremendous forces applied to a piston and connecting rod when a cylinder fires. But what's often forgotten are the tremendous forced applied to a piston and connecting rod when the piston goes up at high speed speed and then has to come to a dead stop before being pulled down again at high speed.
@@garypeatling7927 That isn't why, 2 strokes have the exact same forces, what limits 4 strokes is/was valve float, Ducati had/has a desmodromic system where valves were opened and closed by cams and often ran 11,000 to 12,000 rpm back before modern high tensile strength metals. Honda currently has a 250cc with a 19,000 rpm redline. And that's not even going into F1 where 20,000 rpm V6s are common. I know there was an rpm cap, there were engines faster than that.
Man lots of good info on this video. Agree with you that people want to sweep things under the rug when things go wrong. (Myself included). Can’t wait to see what you put in there next. Learning from this makes me want to get forged pistons and rods from Callies or some other place like that.
I did the exact same thing to my 1985 S-10 2.5L Iron Duke motor by putting it in neutral and flooring it, seeing how high it would rev. It rev'd pretty high... then BAM... piston exploded. In my case the entire piston shattered, then I had just the rod and pin rattling around in the cylinder.. it was SO LOUD, but awesome at the same time. Good Times!
I was thinking all along what you said at the very end of the video. I think it was that hot intake air temperature that did it. Piston and rings swelled up inside the bore and made that piston a little too hard to pull back down and it just ripped the skirt right off. That had to have been what happened. You got to realize, the temperature you’re seeing coming into the engine that’s all the way up in the intake. By the time you go to compress that gas before it is ignited it’s only going to heat up even more! When you compress gas together rapidly it heats up rapidly, even without igniting the mixture. By the time the spark plug hit that intake charge was surely a few hundred degrees more, if not over 1000 degrees. Plus, your back cylinders are always going to run a bit hotter than the front ones, they’re the last ones to see the coolant in the block before it goes through the cylinder heads and is cooled through the radiator. Was the engine sitting and allowed to cool way down between passes? We all know that metal expands when heated. That’s why they say to never flog a performance car when the engine is cold. Everything needs time to warm up to operating temps to allow the tolerances to tighten up. Hope this all helps
I agree with the comment/ theory that all the parts and engines are "mass-produced" and that could be the issue. In "blown" engines (positive displacement and or turbo supercharged or composite supercharged & turbocharged engines) the smallest of issues can become major issues in a heartbeat. I have built and raced and maintained 2 and 4 stroke motorcycle road racing engines as well as 1, 2 (twin) and 4-row radial military aircraft engines prior to computer data logging abilities and had to rely on post-event evaluations as to why engines failed. I would personally believe if I had to point to a single item/ issue it would be the cost-saving measure of the factory not using a torque plate while boring/ honing the cylinders. The difference is tiny by any standards but "can be" significant during the extremes encountered by any engine not designed from the onset as a "blown" engine. The levels of stresses involved accelerate so quickly and suddenly that it can be almost impossible to catch.
Great video,I have a ktm 690 engine on my bench with similar damage,I have theorized on what may have caused it but not really come to a strong conclusion....nice info in this video
That happened to a 10,000 mile 4.6 Ford 2v that I owned. Plug pieces scattered and welded to the piston top. I was running a Vortech with no intercooler racing on a hot summer day. The rod came a knocking on the block lol. It took out my valves as well so I needed a total rebuild
Haven't seen any of your videos before - very well done and excellent points raised! High ring pack is for emissions and power, lower is for top land strength. Were you able to check the remains of the connecting rod small end - if it failed it may have allowed the piston to rack sideways a little, stressing the pin area of the piston until it failed? I think, though, you and your buddies called it, though - poor piston quality allowed the 'pin bosses to fail.
That piston isnt "forged", or actually extruded, its a casting as it has cast in numbers inside the crown. It was simply termically/mechanically stressed beyond design parameters. Amazing that people expect them to survive racing and that they actually do in many cases.
@@whatchu_talkin_john_willis Maybe my grammatics are bad, I tried to say that the piston is cast and at the same time clarify that what's called a forged piston actually is extruded. Aluminium can not be forged, its instead heated and pressed into shape in a special process.
You are right and that is one reason...its normally heat related this can be due to detonation...but the pistons tops and the plugs were the wrong colour...they normally have a white coating from running lean....as he said in the end of the video the air intake temp spiked....I would say this was blow bye from 7 being forced into the intake through the crank breather...this is what probably melted the plugs due to cylinder temp being too high.....
Logs showed zero STKR. I showed that in the video as well. Not saying detonation didn't occur, but if it did the car didn't pick it up and the pistons didn't show signs either as you saw.
@@SpeedysGarage you said in the video the logs showed timing being pulled. Then you tear it down and there's evidence of detonation everywhere , melted plugs, broken ceramic on the plugs. And then you comment contradicting what you say in the video lol. Detonation doesn't always occur on the top of the Piston, usually when you're on the edge it starts at the ring lands.
I don't have time to type it all out here, just go back and watch the video again if it's not clear. Timing being pulled wasn't knock and I'm sure you know that 0 degrees of timing with 17psi of boost at WOT causes many problems (lots of heat). That's what we see here, but the problem was something else. Max timing in the tune was a paltry 10.5 deg. I've been running almost the same tune and pulley on the new motor for about a year with the same 93 fuel as well. Watch some of the newer content to see that we ended up with a 9.83 at 141mph.
Wow, a floating piston during a quarter mile running 10s...probably just built for 6k rpm on a factory motor of 800hp, running 7k rpm on stock rods and pistons will give on a Hellcat...lesson learned..forged pistons and rods built for racing...great video along with data logging of the failure 👍
I'm pretty sure a stock hellcat uses forged rods and a forged crank and I thought the Pistons were forged to I mean I don't think Dodge is that dumb to warranty a 800 horsepower motor and not use a forged lower end AKA short block that's why they absolutely do not recommend pudding a supercharger or turbocharger on a non hellcat Challenger cuz the lower end of the motor is not forged parts
@@kennethjanosick5939 These engines, and also the LS Chevys, are well engineered to work and deliver an excellent power curve at a designated operating range. However, when tuning, and the installation of power adders like forced induction or nitrous come into play, these engines are delivering power beyond what the bean counters (engineers) anticipated. We got to work on some LS engines that originally came from a specialty division of GM Mortorsports, and they had Callies forged cranks & rods, with JE pistons. No hypereutectic pistons or powdered metal rods in those engines.
When metal parts fail, it is almost always at a sharp corner. Threaded parts fail at the root of the thread. Parts with grooves fail at corner of the groove. That's why these type of parts are engineered with a radius at the root of threads and corners of other parts. The larger the radius, the stronger the part. A sharp corner causes a stress rise in the part. It is possible that the oil ring grooves of some pistons have a sharper corner than others, caused by tool wear during production. Also if the oil passages have a sharp corner where they meet the oil ring groove, it would cause a strees rise and potential failure spot.
I think you are right, since the parts are made for mass production you will see stronger than spec parts. Parts that meet but don't vastly exceed the tolerances dodge specified for the order may fail unexpectedly.
Great video speedy! Now I know we should be worried about when seeing a knock but nothing shown on a knock sensor could be indicating a serious bottom end problem !
The pattern of breakage on the piston looks like fatigue failure. Usually has a dull, satin type appearance from the cracks gradually progressing before it fails catastrophically. The final sudden fractures will be more shiny and metallic in appearance. That's also where you'd expect to see it. Those holes are at least drilled and not cast slots, but still they are stress risers.
Might have just been a perfect storm of stuff. Defective piston cast and cylinder just a bit out of round. Like you said these are mass produced parts. Quality control isn't as detailed oriented when it's a numbers game. Doesn't make it a bad product but it is man made. We haven't made anything that is perfect all the time. Great detective work and thanks for putting it out there.
Totally agree and like said in old comment... the hellpuss is not torque plate honed and I have seen two that seen 7000+ with wrist pin pulling out back of piston diamond pistons in the new set up with alot more bottom end also threw the blower in the corner added twin 88 ball bearing percisions added fuel injector bung to a sheet metal intake I built for the car.. the factory rearend let go on last dyno pull we knew it was on deck before we even started the tuning that hellpuss put 1691 down and still has more in it good luck with yours like the vidga
Awesome Speedy《☆》Definitely a Parts Lottery with stock Hemi engines. FCA needs to re-evaluate parts suppliers & quality control. The 6.2s are having piston issues and the 5.7s are having lifter/cam issues. Good luck with GoMango🤓☻🤠
Over 60% of the late model Hemi i have re manufactured (aprox 25 longblocks) had failed due to intake seats coming loose and breaking. If your rebuilding an engine with a seat failure make shure you pressure wash your intake manifold really good. Try to get every port from every angle possible. There have been reports of fresh rebuilds pulling pieces of broken seat debris into the cylinders under heavy vacuum scenarios. Some after market gaskets have a screen embedded in the intake gasket to prevent this from happening, but im shure they will adversely affect top end performance. Any sign of issues i remove the seats, machine and install new seat inserts. If there not getting replaced i will steak around the seats using a center punch to ensure the dont move.
Looks like the pistons use an offset pin which is great for making torque...but it also increases the side thrust on the skirts. Anything with offset pins to me means you really watch the RPM's and never exceed the factory redline or skirt failures will happen. Bet aftermarket pistons are symmetrical pin design which will hurt the bottom end torque production a bit but will be more reliable at higher revs.
My buddy had a 318LA that had a similar problem, except part of the piston skirt broke off and wedged itself in the cylinder walls (It's on my channel) and it seized up the wrist pin on that cylinder and a few others, our guess was that it was ran low on oil at one point and when he got it (and he ran that thing hard) that it weakened it up causing it to fail. Could have been as simple as bad lubrication at that moment
Similar failure found on entirely different engine. Found oil squirters for piston blocked, overheated piston momentarily locked ripping wrist pin out of bottom. Remaining lower portion disintegrated so rod and wrist pin were flopping up down in bore. Rod was long enough that didnt jam and break but still had bend poss due to hitting debris and piston top. In this case heat was the killer.
Only time I've seen failures like that is due to pinging piston rocking in The bore if the piston was cracked you probably would have heard for a while before it failed. And the melted spark plugs seems like a tuning issue to me.
piston rings butted, the crown of the piston is strong enough not to chip off so it sized the piston in the bore, pulled the wristpin out of the piston. rear cylinders run hotter on pretty much any engine due to the coolant inlet being at the front of the engine. couldve gotten one that was on the tight side of factory acceptable piston ring end gap clearances, and then turned the wick up on it.
too much heat , expanded the rings untill they butted, seizing them in the bore, breaking piston tops. Guys who get carried away boosting LS engines without opening the ring gaps have this problem, too.
These a team of blokes on you tube, its a few years old that experiment/destroy engines on a dyno in various ways to see what happens....they showed what too much nitrous does...same as over boosting/lean mixture etc....and your right the rings butt up and break the piston...normally the top ring breaks the piston as this is the hottest part but it normally stays connected to the rod just eats the piston...
Yup ring gaps, seized up top and pulled the pin out. The unusual rocking wear on top of the piston was probably due to the piston developing a crack as the piston was getting to seize prior to complete failure.
Looks like you had some piston skirt damage and rocked the piston till it let go from what the crown is showing. But you didn't show the skirt pieces which is probably the most important pieces to look at. The top 2 ring groves look too good for it to be expansion seizure. Well that and the fact you sucked the crown out with a shop vac
Just a failed piston. I think its a fluke. I believe the factory pistons are actually manufactured by Mahle. Not junk. Those guys know there stuff. My Buddy works for CP Pistons and has nothing but good things to say about Mahle. Id love to see the difference between a Demon/Redeye Piston and Rod assembly versus a Hellcat.
This is good to know. With me just now beginning to modify my hellcat. I am happy that this was just more than likely a one off. Not a factory problem.
You guys are kicking the heck out of those motors. It's amazing they survive what they do. That you ripped the skirt off a stock piston is not surprising.
Wow ...Crazy stuff. Great info. I allways think man i should get a Hellcat and then i reallize its ok to be a little slower with a scat pack. I know .....THIS IS HOW RACING GOES ... been there done that !!👍👍👍👍👍👍
As its been said great video...for a change a genuine informative video, I think your spot on with your theory, manufactures won't admit anything which is a shame a SHIT does happen and word soon spreads and they get a bad name rather than going... yes we've had a batch issue, Along with most manufacturers I know Ford with there ZETEC engine which the vales stuck open in the heads due to machining error.....it took us 8 months of diagnosis's to prove it was that before they agreed with our findings, they never recalled them but dealt with then on failure base only, Lexus first diesel the piston rings basically re-bored the engine due to the coating being wrong....again only dealt with failures and that's only two of many I've seen in my short life on this planet....may be if you approach Dodge and show your finding they may offer a goodwill payment?...if you don't ask you don't get.....please do more like this as your understanding and not bias in your view you accept things go wrong which is a great lesson for us all.
Another great video. I lost the “strap” and porcelain on both plugs in #2 cylinder. Burnt hole in exhaust valve. My tuner thought it was a device I had plugged into the OBD port. (Discreet comment) I’d like to know if any of your members or contact have a theory. 2 and 7 are sisters but with the supercharger in between I’m not convinced the heat /fire jumped. I have seen jumping on older carburetor / intake manifolds. Thanks again for the informative video.
Usually burned plugs are a sign of extreme heat or a lean condition. My only other thought is a bad injector, but it would have shown problems before #7 broke I'd think. Gonna send the injectors out for testing and will post content on that to see what we find.
I've seen plenty of pistons break at the oil ring groove on different makes. It's high RPM on a part not really designed to live at those piston speed per mile speeds. Mopar built these cars so folks could race them and live with the damage and develop the engines to make power and live a little longer themselves . it's a story as old as the car.
The one time that happened to me was in my slant 6. I over heated the engine and a piston seized pulling the rod from the piston and putting a hole through the block. I suspect that pistons tolerances were a little tight and subject to heat. If you race, build your own engines. I've raced for 30+ years. MOPAR!
That's crazy...I've seen the wear on the sides of the pistons like you got, but not the ripped-out wrist pin...although that is logical if the piston seized in the bore. It was definitely rocking in the bore...and the bore probably wasn't round to begin with as speculated. And if they are not torque plate honing the bores...Mopar probably sets the pistons up a little loose to allow for that. All of it can add up to this...and it sucks to be the one with a blown motor. Looking forward to hearing what you went with as an upgrade...
On my trackhawk Snapped my rod one #1 and it dropped a valve in that same cylinder. I was about 1k hp. Just got my new built engine in now doing tuning shake downs now
I had a 5.7 in a Durango do the same thing on startup bone stock engine daily driver didn't hurt the block at all so I put a new Mopar piston and rod in it and never had anymore problems with it and it was also number 7 done a quiet a few hemi now and always number 7 piston
Do you still have the data logs when you were at the track when it was blowing through the shift points? I'd like to take a look at them, I have a few things I'm curious about.
RPM kills engines. I have seen this on any engine a lot with floating wrist pins. Pistons with hardly any skirt and floating pins rock more and will break and leave the piston at the top of the engine. Piston ring gaps can also close tight and leave the piston at the top. Floating pistons get get larger as time goes by and when they jurk the piston back down can break the piston or rod. When you press any engine to its limits you can expect anything to break after time. Just the way the game is played. Its a money game if you can afford to play.
yup... those ring gaps are crazy and the rings are so thin, how did they even think they would work in the first place... cuz, you know, Mopar runs so cool and all. I didn't even think about how bad those wrist pins are. Like the pins on a Harbor Freight breaker bar.
I wish someone would help me pay for my engine mine just blew a piston threw the bottom of the block 😒 am sick over this as my Hellcat challenger is my baby. Your videos are very informative and learn alot from you!
I don’t know the specifics of the hellcat engines, but I recently saw that Power Auto Media shootout that features the mopar vs LS vs Coyote and both tha LS and Hemi teams had to replace the pistons because they said the stock pistons won’t handle a lot of boost, basically they come apart.
I have a 1954 354 Fire Power hemi and a buddy of mine has a hell cat hemi. I was blown away at the differences. Even the way the bearing caps are split. But yeah I'd say a fluke of a failure. Me old school carbs and engine, no juice so no "check tunes data". Seems to me some major piston slap tore it apart at high revs.
Not a true statement. I've got a redeye which is a demon motor exactly. They are very slightly better on a harder rod and connector ring. The cam is better and that's all. Seriously I have a blown one.
a few things . that inlet valve will be bent...!!!! enough to light the inlet thats what increased iat's.. ring gap leaves pistons behind and rev's . those pistons are very weak looking around the oil scavenge holes.. the rock marks are probably from the failure it wont live at those revs with a broken skirt and you would have heard it.. the fact that other plugs have melted probably happened when iats went through the roof.. ring gaps are 3thou/inch for na.. double that for what your running.. also need more of a look at that rod or the pieces and the bottom of the block. if it pulled the pin out of the piston it would have danced around and kicked a leg out. how has it left the big end attached to the crank and still turning.. nice vid.. keep looking.. thankyou
The rod and pin didn't fail the pistion did it probably over heated the pistion and it seizied. At the top of the stroke and ript the pin out I'm curious if there was drop in boost pressure before the it failed?
