Hellcat down

[Bowlerguy92]

Some of you may know I've been a member here for a little while now, actively drag racing my 2022 HCREWB chasing a 9 second slip with help from @Jon-MooredPerformanceLLC. Unfortunately the fun came crashing down at a track rental about a month ago where I experienced an engine failure on my first and only pass of the day.

Long story short, I completed the pass (slow, only a 10.4 and with good air) and upon coming back down for the slip noticed my engine was misfiring badly with a distinct lack of responsiveness from the gas pedal. I thought maybe a quick cool down or a tune reload or something might fix it so I parked it and shut it down. Tried to crank it again and no luck. There was too much resistance for the starter to even turn the car over and it sounded pretty much like a dead battery. Thinking that may actually for some reason be the issue, I got a jump from @2ndAmend which provided enough juice I guess for the starter to overcome the resistance and I got the engine fired. Immediately, white smoke began pouring out the tailpipe, pulley tensioner bouncing around like crazy. Uh oh, I thought...something is really fucked here. I ended up having it towed and it's sat at the speedshop waiting for work in front of it to be completed since then.

Finally this week the shop was able to pull the motor and disassemble and confirmed it was a failure in cylinder 2, which ironically enough Jon told me was his guess weeks ago when we discussed the situation initially. Based on what we can see currently, it appears a lean condition due to an FIC injector failure caused excessive heat buildup in that cylinder, blowing half of my piston off and creating a blowtorch of sorts that actually had tried to cut through the bottom of the block. Basically, I need a new short block and porting of the heads may be required if the machine shop doesn't think they can machine the little bit of damage that those also sustained. $$$$ Jon's guess and observation is that it's likely that these motors just have an inherent weakness in cylinder 2 and that the injector will test out fine. This isn't the first time he's seen this and in multiple cases, it's happened on stock motors.

What the shop did tell me, though, is that the rest of the engine looks great with no visible wear on my pistons or within the other 7 cylinders. Jon's tuning work, to no one's surprise, is excellent and had absolutely nothing to do with this failure. He's actually been great and engaged in this situation and will work with me to help vet quotes from the shop, put me in touch with folks he knows who can build me a short block for a reasonable price, etc.

Anyways, unfortunate that it is, it looks like I'll have an opportunity to possibly throw a 426 stroker kit or something of that nature at it and really build something next level. Photos exist of the damaged engine but I unfortunately didn't receive them tonight. Once I have them, I'll make sure I post them here so you can all see the damage.

Feel free to leave thoughts, ideas, create a prayer circle for a downed brother, etc I'll make sure to update this thread with photos and of course let everyone know what we end up doing with this build.

 

[Jon-MooredPerformanceLLC]

It’s an unfortunate situation. Especially, because we had a conversation of keeping the tune safe and when you asked for more I said I just don’t think it’s worth it and working on the 60 ft was more of a benifet at this point. Or something along those lines
I do think the injector will test fine. That same cylinder has failed from other reputable tuners as well this year. I don’t remember where you were for timing. But it wasn’t much especially for the 100 octane.
One thing I can’t stress enough to everyone is not letting the car heat soak and monitors temps. If I remember right in the log intake manifold temps showed 150 degrees after the burnout. This does not help an already pour performing cylinder. Yes cylinder 2 appears to be the old cylinder 7 issues.

 

[fubar569]

I remember the old cylinder 7 issues. Widespread yet very hush-hush at the same time. I keep making the joke I'm gonna rock this thing til #7 Adele's itself (hello from the other siiiiiiidddddeeeeee).

Build the bottom and send it. You're in good hands.

 

[16GoManGoHC2]

My first engine issue was cylinder 2 and 7, others were perfect. As Jon expressed that 150 degree MAT temp did not help things, I would have never started a run at that beginning temp. Probably butted a ring and it was all over in microseconds when that happens, stock top ring gap is tight, too tight for high boost and hot MAT

 

[fubar569]

I'm still in the habit of referring to temps as IAT1 (pre blower) and IAT2 (post blower) like in the GM world.

150 pre blower doesn't bother me as much because as soon as that throttle slams open it's gonna suck all the cold air in the world.

150 post blower is...well...not good. Stock tune starts to yank stuff at 145 (at least it did in my car) for a reason.

 

[catdad]

Can we go in the tune and slightly give those 2 cylinders more fuel if they are running lean?

 

[Jon-MooredPerformanceLLC]

Can we go in the tune and slightly give those 2 cylinders more fuel if they are running lean?

You can. Question would be how the other cylinders look after doing this. His tune was set to .83. Which is pretty standard. .80 would give more cooling. Factory tune is .87. So the we are already commanding richer. But there are other things to add to fuel suck as cot

 

[Bowlerguy92]

I guess I’ll make sure we do a 180 t stat. This wasn’t even a hot day, it was around 69-70 degrees at the time of the run. I had run it in much much hotter weather earlier in the season. My engine seems to always be heat soaked in these logs.

 

[BULL]

Watching

426 sounds nice

 

[catdad]

You can. Question would be how the other cylinders look after doing this. His tune was set to .83. Which is pretty standard. .80 would give more cooling. Factory tune is .87. So the we are already commanding richer. But there are other things to add to fuel suck as cot

Can you do individual cylinder fuel control? Or is the ecm limited ?

 

[Speedy!]

Been there done that. Mine was cyl 7 on original HC motor. I wonder if there are some machining tolerances not quite perfect that rears its head with these incidents.

I wondered if an injector was my problem as well, but mine all checked fine from an independent lab test.

Sucks when it happens, but a chance to upgrade.

 

[Jon-MooredPerformanceLLC]

Can you do individual cylinder fuel control? Or is the ecm limited ?

Ecm allows fueling per cylinder. What I was saying was the O2s pulling and adding fuel depending on what they smell

 

[16GoManGoHC2]

Ecm allows fueling per cylinder. What I was saying was the O2s pulling and adding fuel depending on what they smell

Exactly, a programed richer cylinder mean leaner other cylinders as the O2 sensors are averaging the exhaust from 4 cylinders. Be nice to have 8 O2 sensors.

 

[DavidKFla]

Exactly, a programed richer cylinder mean leaner other cylinders as the O2 sensors are averaging the exhaust from 4 cylinders. Be nice to have 8 O2 sensors.

And 8 individual egt sensors

 

[16GoManGoHC2]

Been there done that. Mine was cyl 7 on original HC motor. I wonder if there are some machining tolerances not quite perfect that rears its head with these incidents.

I wondered if an injector was my problem as well, but mine all checked fine from an independent lab test.

Sucks when it happens, but a chance to upgrade.

I think it’s cylinder jacket cooling related but opposite what is thought, ie not from hot cylinders but cold cylinders. Colder cylinder liners from colder coolant temps (ie 180 or lower tstats) means even smaller ring gap and piston to wall clearance on an engine designed to run hotter. For every .001” of bore size means .00314” of ring gap. Hot pistons with tight ring gaps in cold bores don’t play nice together. Demon and RE engines are built with larger PTW clearance and ring gap for a reason, higher expected load, ie heat

 

[Speedy!]

I think it’s cylinder jacket cooling related but opposite what is thought, ie not from hot cylinders but cold cylinders. Colder cylinder liners from colder coolant temps (ie 180 or lower tstats) means even smaller ring gap and piston to wall clearance on an engine designed to run hotter. For every .001” of bore size means .00314” of ring gap. Hot pistons with tight ring gaps in cold bores don’t play nice together. Demon and RE engines are built with larger PTW clearance and ring gap for a reason, higher expected load, ie heat

That is an interesting theory. It's odd that on Hellcat it was Cyl 7 you mostly saw issues with and on the RE it's Cyl 2. To be honest, I was a little worried about my RE motor when the SDG worked 2.7 made 20psi. I ran a lot of WOT passes on the street dialing in and changing fuel setup, but only 3 or 4 passes at the track before the car was stolen. Who knows it may have been fine or popped on my next outing. AJ used to always say no more than 850RWHP even for a RE, but I was never sure if that was to sell built motors or what.

 

[Bowlerguy92]

So…..426 short block is what I’m hearing? Do I include a cam? Anyone have recommendations? Not sure what the best path is going forward. Was going to discuss with the shop next week but not sure who they work with or what they can get.

Don’t want to have to do additional supporting mods like built trans, etc.

 

[Speedy!]

I don't know I'd do a 426. Supercharged motors usually like a little less stroke. I'd recommend getting a goal in mind and build the engine around it.

Personally, a forged 6.2L is where I'd go, but I like the stock IHI superchargers too. A 426 will need a much bigger supercharger I think.

 

[Octanewide]

AJ used to always say no more than 850RWHP even for a RE, but I was never sure if that was to sell built motors or what.

So my 792@15 psi is safe..

Sent from my SM-G781V using Tapatalk

 

[Bowlerguy92]

I don't know I'd do a 426. Supercharged motors usually like a little less stroke. I'd recommend getting a goal in mind and build the engine around it.

Personally, a forged 6.2L is where I'd go, but I like the stock IHI superchargers too. A 426 will need a much bigger supercharger I think.

Gotcha. Any recommendations from you or Jon there? Whatever it takes to never have this happen again and give me something that will let me turn the boost up a bit more if I wanted to in the future.