Another blown motor

[vortecd]

We always can learn from history so brought this back up for some info. It is not always number 7 that has a failure but does number 7 have the most and does anyone have a reason why?

 

[16GoManGoHC2]

We always can learn from history so brought this back up for some info. It is not always number 7 that has a failure but does number 7 have the most and does anyone have a reason why?

My number 7, typical failure, piston popped at thinnest point under a valve relief. A few theories, one is the corner cylinders run the leanest causing them to run hottest which leads to ring butting of the tightly gapped stock upper ring and pops the weakest part of the piston out exposing the ring to even more direct heat, the rings start to delaminate and leak more causing even more heat and expansion until the piston locks up at TDC on turnaround of the exhaust stroke and the bottom of the piston gets torn off and makes its last trip down the bore and out the bottom as on the next up stroke snaps the rod in half and makes a window to the world with the wrist pin like a shot gun slug.



Replaced with these, .330” of meat between the fire storm and the ring, hard anodized top and ring lands and pin bores, PTFE coated bottoms and skirts. .250 wall H13 DLC pins with very close pin boss spacing on the piston keep crown flex to a minimum. Connected by a 4340 Manley H-Tuff rod on King Coated bearings. Top ring gap .026” verse stock .014-.018” which I think is the killer of these engines. Probably why a colder 180 Tstat helps and hot IAT’s and ambient temps doesn’t. Hoping this lasts a bit longer, someday see a bit of spray too possibly.

 

[Speedy!]

We've learned quite a lot in the two years since this post was started as well. What I've seen is more standard Hellcat engines fail (stock or modified) than Redeyes. Kinda makes sense considering the Redeye engine is the same as the Demon and it's designed for 840HP in that model so it gave 133 more HP of buffer over the standard Hellcat.

I purchased a "Demon Crate Engine" based on P/N but what showed up was a Redeye long block as it had black valve covers instead of the red I expected. Paperwork that came with my long block said to swap the valve covers from original Demon engine if it was going in a Demon. Boo.

My research said the Demon/RE engines were 30% stronger, better oiling system, cam, and other improvements. At the time I wasn't sure if all that was just marketing mumbo jumbo but this engine has worked very well and been trouble free (knock on wood). It was designed for the Demon which is intended to be drag raced so some of the stuff makes sense like baffles in the oil pan for slosh at launch, etc. Also the fact it got a 2.7L supercharger making 14psi vs the Hellcat 2.4L at 11psi. Aircharge for aircharge the 2.7L at 14 is very close to what my 2.72 pulley makes on my 2.4L.

The other thing is the factory 91-93 octane calibrations are a bit less aggressive than the standard Hellcat. Not a ton, but sometimes a little goes a long way.

We're pretty far in to this platform now. I wouldn't expect to see a lot blowing up these days if some common sense is applied. However we also won't see a ton of people setting the world on fire with stock engines either. The limits are well known now.

AJ (Hemituner) who's well respected says no more than 850RWHP on either Hellcat or Redeye/Demon stock engines last we spoke. My original Hellcat motor broke at less than that though and now that I've learned a few things I think it was all the detonation it saw when stock on 93 gas. I think that had started taking a toll and by the time I put a pulley on it just gave up 3,000 miles later. Personally I'd stop about 800RWHP on a Hellcat. Redeye I think 900RWHP is probably OK but start going much more than that and you're upping the ante IMO.

The Direct Connection parts kind of align with this as well. You'll notice there is no stage 2 for the Hellcat like there is a RE.

I keep hoping Dodge will release one more upgrade to this platform as a send off and I can pick one up. It's the reason I didn't go full built motor when mine broke and opted for a documented Mopar crate engine. I figured selling the car on others would feel better about that than some built motor I chose. I'd also been there done that with the full build on the old car and just didn't wanna get in to all that again. It's worked out well so far.

 

[Demoniccat]

It’s starting to become more evident not a lot of extra HP is able to be applied with reasonable longevity assured. No doubt some have pushed these with much more HP, and lots of street/strip miles. But if the slightest thing is off be it timing, piston rod speed feet/per second from excessive revs, loss of thermal control then possibly aggravated by driveline shock into the engines rotating assembly, etc then premature catastrophic failure is almost a certainly. Could it be the engineers did in fact know there design limits with a high level of test data. I think so Because Some of the earljest Engineering publications on the Hellcat specification in the automotive world constantly would ask that gnawing question why the smaller 6.2 vs the Apache 6.4 displacement wasn’t used. Every FCA interview and article seemed to all point back to bore/stroke ratio, and most likely more emissions from more displacement, to keep the stroke down to control rod stressing from piston rod speed and loading. @16GoManGoHC2 is dead on with his recipe with the rotating assembly. Most of the aggressive Gen 3 builds that are staying together are higher quality forged rotating assemblies. Again I realize there is several proving me wrong and being the exception to the rule with failure rate by pounding and pushing theses engines very hard and staying together. But overall the ones that are staying together making the good HP on stock internals are the ones going to the reputable tuners with good tunes, quality gas, E85, E85gas flex tune. Again there are always the exceptions. Let na sayer flood gates open, just my .02

 

[Demoniccat]

As far as temperature control, I do find it ironic that I was told if I dump a 180 degree T-stat in the RE, that I would void my warrant. Now if I purchase the stage kits coming out soon the T stat goes in with warranty go figure. They absolutely know some addition failure rate will ensue if temperatures aren’t controlled, not to mention much more easy to hit HP mark. Wonder how they got around emission. They claimed higher temps were needed to get the emissions to jive.

 

[Speedy!]

@Demoniccat things that make you go hmmmm LOL.

The cars I've seen that really get leaned on and survive all run the best fuel available. I think that's a big one for longevity. The OST shop Hellcat is a prime example. They've run 8.70s in that car on the stock motor and Mike drives it around quite a bit on the street. As far as I know they've only ever raced it on very high quality race fuel. I bet it's the same for @Linda's Hell Cat Topcat that HHP races quite a lot. They may have upgraded the engine now, but they ran the stock motor for a very long time.

Demonolgy is another. I think I heard him say he put over 2000 passes on the stock Demon motor but he always ran that GT fuels (can't remember which one maybe 260) until he went to E85. Eventually he replaced the engine and he did have several rods starting to bend but that car was making well over 1000RWHP by then. I think a head gasket was what caused him to start a new engine build.

 

[vortecd]

My number 7, typical failure, piston popped at thinnest point under a valve relief. A few theories, one is the corner cylinders run the leanest causing them to run hottest which leads to ring butting of the tightly gapped stock upper ring and pops the weakest part of the piston out exposing the ring to even more direct heat, the rings start to delaminate and leak more causing even more heat and expansion until the piston locks up at TDC on turnaround of the exhaust stroke and the bottom of the piston gets torn off and makes its last trip down the bore and out the bottom as on the next up stroke snaps the rod in half and makes a window to the world with the wrist pin like a shot gun slug.

View attachment 63612 View attachment 63613 View attachment 63614

Replaced with these, .330” of meat between the fire storm and the ring, hard anodized top and ring lands and pin bores, PTFE coated bottoms and skirts. .250 wall H13 DLC pins with very close pin boss spacing on the piston keep crown flex to a minimum. Connected by a 4340 Manley H-Tuff rod on King Coated bearings. Top ring gap .026” verse stock .014-.018” which I think is the killer of these engines. Probably why a colder 180 Tstat helps and hot IAT’s and ambient temps doesn’t. Hoping this lasts a bit longer, someday see a bit of spray too possibly.


View attachment 63615 View attachment 63616 View attachment 63617

You were talking I beam but ended up going H. I had those Manley rods in my 13 mustang build. On my 87 mustang build I had Eagle H beams. I have been more partial to the H beam

 

[16GoManGoHC2]

You were talking I beam but ended up going H. I had those Manley rods in my 13 mustang build. On my 87 mustang build I had Eagle H beams. I have been more partial to the H beam

I wanted I beam rods but got these H-Tuff ones for a steal, 1/3 the price of the I’s so I couldn’t pass them up. According to a Manley Engineer Their H-Tuffs are almost twice as strong as regular H beams and approach the strength of their 4340 I beams, now going to 300M I beams no comparison but their boo-koo bucks and not warranted on a stock crank and caps studded or not.

 

[fubar569]

*looks at dyno sheets*

*whistles in YOLO*

Hope the ol girl sticks it out for one more season at least. Lol.

 

[Mrproper86]

We've learned quite a lot in the two years since this post was started as well. What I've seen is more standard Hellcat engines fail (stock or modified) than Redeyes. Kinda makes sense considering the Redeye engine is the same as the Demon and it's designed for 840HP in that model so it gave 133 more HP of buffer over the standard Hellcat.

I purchased a "Demon Crate Engine" based on P/N but what showed up was a Redeye long block as it had black valve covers instead of the red I expected. Paperwork that came with my long block said to swap the valve covers from original Demon engine if it was going in a Demon. Boo.

My research said the Demon/RE engines were 30% stronger, better oiling system, cam, and other improvements. At the time I wasn't sure if all that was just marketing mumbo jumbo but this engine has worked very well and been trouble free (knock on wood). It was designed for the Demon which is intended to be drag raced so some of the stuff makes sense like baffles in the oil pan for slosh at launch, etc. Also the fact it got a 2.7L supercharger making 14psi vs the Hellcat 2.4L at 11psi. Aircharge for aircharge the 2.7L at 14 is very close to what my 2.72 pulley makes on my 2.4L.

The other thing is the factory 91-93 octane calibrations are a bit less aggressive than the standard Hellcat. Not a ton, but sometimes a little goes a long way.

We're pretty far in to this platform now. I wouldn't expect to see a lot blowing up these days if some common sense is applied. However we also won't see a ton of people setting the world on fire with stock engines either. The limits are well known now.

AJ (Hemituner) who's well respected says no more than 850RWHP on either Hellcat or Redeye/Demon stock engines last we spoke. My original Hellcat motor broke at less than that though and now that I've learned a few things I think it was all the detonation it saw when stock on 93 gas. I think that had started taking a toll and by the time I put a pulley on it just gave up 3,000 miles later. Personally I'd stop about 800RWHP on a Hellcat. Redeye I think 900RWHP is probably OK but start going much more than that and you're upping the ante IMO.

The Direct Connection parts kind of align with this as well. You'll notice there is no stage 2 for the Hellcat like there is a RE.

I keep hoping Dodge will release one more upgrade to this platform as a send off and I can pick one up. It's the reason I didn't go full built motor when mine broke and opted for a documented Mopar crate engine. I figured selling the car on others would feel better about that than some built motor I chose. I'd also been there done that with the full build on the old car and just didn't wanna get in to all that again. It's worked out well so far.

The stage 1 on the hellcat is the same. Pulley and tune on redeye and hellcats. The hellcat wont get the high octane option probably because it runs a single fuel pump and smaller injectors compared to the redeye dual fuel pumps and demon injectors. But stage 2 is in development

 

[Speedy!]

It's not the same though. Hellcat has a 2.4L supercharger RE is a 2.7L so the same pulley will make a lot more power on the 2.7L.

The point is the Hellcat looks to only get a measly 40HP bump. RE gets quite a bit more and "stage III" in development. They're worried about something on the Hellcat motor and I be it's the rods.

 

[Hickster]

88 in Tampa on Friday.

 

[Magnified]

Wish I'd held onto my Charger now... lol