Crankshaft snout snapped

[ENPhoto]

How many cobra jets are there out in the wild?

makes me wonder why the cobra jet crank bolt was/is longer than the 5.4L lightning/Navi/F-150 ones were

M-6303-C54SC4

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[sigintel]

Keep in mind: these are interference engines.
If you over rev and catch a valve, you lockup the valve train and break the snout. If you bind the chain, the gear “climbs” the chain and slams the crank into the front main repeatedly as its jacking the crank snout with the full engine torque and inertia.
Snout damage at high rpm can result in cyclical failure waaaayyyy after the incident that caused the damage.

 

[Mustanggt5.02011]

Well, add another whipple , stock diameter ATI, MMR TG/OPG to the snapped crank list. Happened Friday night coming back home from a night racing at Numidia. I was in 6th gear cruising along around 2,000 rpm and all of a sudden it let go.

For those of you this has happened to, what dampener/balancer did you go with on your rebuild/new motor? Has anyone gone with crank support on their new setup?

It's frustrating as all hell as I spent the money on upgrading these parts to prevent something like this from happening. Motor has less than 13k miles on it and has had the whipple on it since day 1, installed at the dealer. The ATI dampener, TG, and OPG were dealer installed around the 7,000 mile mark after reading what happend to Shawn's motor with the failed OPG thinking it would be cheap insurance.

Car was making 780ish whp. I had just run my personal best time that night as well with a 10.73 at 131.75mph on a 1.61 60 ft 93 octane with Lucas oil octane booster 4120 race weight.

I'll be having Jensen Performance doing the new motor/rebuild. Hoping I can have something built to handle 800-900 whp for less than $10k. Initial over the phone quote for labor of removing and installing new engine was $1,000 to $1,500.

Sorry to hear this about your motor. Sucks after spending money on upgraded parts to have this happen. The price you were quoted (if true) is very good. The R&R on book time is about 20-21 hours so we charge about $2500 to pull and put back in. Good luck with the new build!!!

 

[Barrel]

Add me to the crankshaft failures. Didn't catastrophically let go, though, thank goodness. Finished my last half-mile event with a weird miss at high-rpm so I called it on day 2 of racing in the afternoon. Last pass was at 168mph and then put it on the trailer. Got it home and was cleaning stuff up when I noticed a wobble to the crank pulleys. When everything came apart the snout was beat to snot and the timing chains were also beaten up pretty good. Only thing keeping everything together was a really tight crank bolt. So the crank and all timing gear needs replacing.

Gonna check with the shop today to see if they've gotten to dropping the oil and taking the heads off to see what's salvageable in the engine. There was a lot of metal around the timing stuff. Car actually ran fine - wasn't giving me any trouble when loading/unloading it. Even drove it briefly troubleshooting a brake issue. Then noticed the wobble in the garage and that was that.

Race car problems.

ATI balancer for the PC Stage 2 system. Don't have the part number in front of me.

 

[stang17]

Add me to the crankshaft failures. Didn't catastrophically let go, though, thank goodness. Finished my last half-mile event with a weird miss at high-rpm so I called it on day 2 of racing in the afternoon. Last pass was at 168mph and then put it on the trailer. Got it home and was cleaning stuff up when I noticed a wobble to the crank pulleys. When everything came apart the snout was beat to snot and the timing chains were also beaten up pretty good. Only thing keeping everything together was a really tight crank bolt. So the crank and all timing gear needs replacing.

Gonna check with the shop today to see if they've gotten to dropping the oil and taking the heads off to see what's salvageable in the engine. There was a lot of metal around the timing stuff. Car actually ran fine - wasn't giving me any trouble when loading/unloading it. Even drove it briefly troubleshooting a brake issue. Then noticed the wobble in the garage and that was that.

Race car problems.

ATI balancer for the PC Stage 2 system. Don't have the part number in front of me.

Sorry to hear, but I guess misery loves company. Did you install the ATI yourself or did a shop do it for you?

 

[Barrel]

Sorry to hear, but I guess misery loves company. Did you install the ATI yourself or did a shop do it for you?

Shop did it. It's got well over 150 half mile passes on this setup so I don't think it was installation error. There was a crack all along damper and into the snout. The car was really close to having it all come apart. Can't believe I finished another pass with it in this condition. Rev limiter is at 7600RPM and the car has been WOT past 170MPH for most of those 150 passes. I have my D1SC spinning at max impeller speed at redline.

Was planning on adding more power anyway and got everything to do it knowing that the motor wouldn't take it forever. Just didn't think the crank would be what would let go first.

 

[stang17]

I've read somewhere these cranks should be good to 1500 hp. I'm still up in the air with what I'm going to do with the rebuild. Half tempted to sell the whipple kit and just do a nasty NA build around the 5.2 aluminator XS motor. Advertised to make 580hp on 93.

 

[Tommy V]

Shop did it. It's got well over 150 half mile passes on this setup so I don't think it was installation error. There was a crack all along damper and into the snout. The car was really close to having it all come apart. Can't believe I finished another pass with it in this condition. Rev limiter is at 7600RPM and the car has been WOT past 170MPH for most of those 150 passes. I have my D1SC spinning at max impeller speed at redline.

Was planning on adding more power anyway and got everything to do it knowing that the motor wouldn't take it forever. Just didn't think the crank would be what would let go first.

You had a built motor correct if so he did the rebuild?

 

[Barrel]

You had a built motor correct if so he did the rebuild?

Small engine builder in NC did the build a couple of years ago. Motor itself is solid.

So I just got back from the shop. The damage is pretty substantial. The keyway on the crank let go and cracked a few inches up the crank along with the balancer - so both cracked and nearly split open. The damage then through rotation and vibration pulverized both the crank and crank timing gear and sent a little bit of a metal slurry through the motor. There's a good bit of metal missing but we haven't cracked open the motor to find out. Not that it matters a whole lot since the whole thing needs to come apart for a new rotating assembly.

I'm basically hoping the heads are in good enough shape. I'm replacing cams and springs anyway as part of my new build. I'm gonna start shopping for short blocks. Ugh!

 

[olaosunt]

Sorry for your loss ... I have been there ....too many times and it still hurts every time .

Why I started building “spares “ cause honestly it’s only a matter of time before you need one .

 

[ahl395]

I'm curious how some of these are being installed. I keep hearing "I torqued it to spec" or to 110ft. lbs or whatever, but that doesn't mean that the balancer was seated fully before throwing on the bolt and using the torque wrench. When I installed my ATI, I used an installation tool that I got from Beefcake that inserted a threaded rod and had a big threaded sleeve that was used to pull the balancer on. You could feel it when the balancer seated because the amount of torque it took to keep tightening that sleeve got extremely high. In other words, it suddenly got really hard to tighten further and you could tell it wouldn't go on any more. I now have 30k miles on that setup with a whipple and no issues. I highly recommend picking up a proper install tool if you are going to use an aftermarket balancer. Using an installation bolt to pull it on, then switching to the normal bolt for the rest of the way is just prone to too many mistakes. Bottoming out the install bolt, or not seating all the way could both lead to crank snout failure.

I've done it the "dirty" way several times with an install bolt. If you heat up the balancer real hot and oil the crank snout it will slide on like butter and seat properly. 50k miles on mine with an ATI and 8 rib Procharger. Personally I think the biggest problem is people not heating the balancers when installing so it doesnt slide on the crank easy and doesnt seat all the way back.

 

[ramirj2]

Shop did it. It's got well over 150 half mile passes on this setup so I don't think it was installation error. There was a crack all along damper and into the snout. The car was really close to having it all come apart. Can't believe I finished another pass with it in this condition. Rev limiter is at 7600RPM and the car has been WOT past 170MPH for most of those 150 passes. I have my D1SC spinning at max impeller speed at redline.

Was planning on adding more power anyway and got everything to do it knowing that the motor wouldn't take it forever. Just didn't think the crank would be what would let go first.

Sorry for your loss!
Another ATI!
Although I didn’t ran mine as much as you. Mine lasted for 3 years, 2 half mile events, 2 roll race events, and 30+ 1/4 mile runs broke mi snout due to mi installation error (not seated properly). No hints whatsoever until that 3-4 shift at 7,700.

 

[Tommy V]

Small engine builder in NC did the build a couple of years ago. Motor itself is solid.

So I just got back from the shop. The damage is pretty substantial. The keyway on the crank let go and cracked a few inches up the crank along with the balancer - so both cracked and nearly split open. The damage then through rotation and vibration pulverized both the crank and crank timing gear and sent a little bit of a metal slurry through the motor. There's a good bit of metal missing but we haven't cracked open the motor to find out. Not that it matters a whole lot since the whole thing needs to come apart for a new rotating assembly.

I'm basically hoping the heads are in good enough shape. I'm replacing cams and springs anyway as part of my new build. I'm gonna start shopping for short blocks. Ugh!

Was it TKM

Small engine builder in NC did the build a couple of years ago. Motor itself is solid.

So I just got back from the shop. The damage is pretty substantial. The keyway on the crank let go and cracked a few inches up the crank along with the balancer - so both cracked and nearly split open. The damage then through rotation and vibration pulverized both the crank and crank timing gear and sent a little bit of a metal slurry through the motor. There's a good bit of metal missing but we haven't cracked open the motor to find out. Not that it matters a whole lot since the whole thing needs to come apart for a new rotating assembly.

I'm basically hoping the heads are in good enough shape. I'm replacing cams and springs anyway as part of my new build. I'm gonna start shopping for short blocks. Ugh!

Wonder if doing a double keyway would be better?But that is more cut out of the crank.Was the shop TKM?I just talked to them about doing a shortblock for me.

 

[Barrel]

Was it TKM

Wonder if doing a double keyway would be better?But that is more cut out of the crank.Was the shop TKM?I just talked to them about doing a shortblock for me.

Jerimiah Hussey of MPS in NC. He's been on deployment and so his whole operation has been idle for I think a couple of years now. He built my motor in '16.

Rev Auto is suggesting that I do a double keyway for the new build. Right now I'm deciding on rolling the dice on an MMR motor or going with a pricier L&M or MPR shortblock.

Open to other builders too. Just want to spend this money once lol.

 

[whatsup62]

Rev Auto is suggesting that I do a double keyway for the new build.

I double keyed the one I am putting together now.
Might look at these guys....using good stuff for internals ...same setup as mine - Gen 2 sleeved block with Molnar rods and Diamond MOD2K pistons.
https://www.facebook.com/search/top/?q=tafindustriesllc

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