Blew up my Boss motor on a track day - Why???

[BKBoss302]

Well I blew up my motor on my 4th track day this year. Does anyone have some insight as to why?
Here are the details:
Stock motor with 11,000 miles, no cats, X-pipe into Borla mufflers, washable air filter in stock airbox, Sebra 72 row oil cooler, fresh oil, Ford Track Key, 91 octane non-oxygenated gas
Number 8 piston is exploded and the rod with no cap on it is wedged in the area between the heads
Number 4 piston is still in the cylinder and 1/2 the rod is still connected to the crankshaft
Two big holes in the block on either side
Motor is still in the car until next week.
Bigger question - how do I prevent it from happening again?

 

[PatientZero]

OUCH!

Can you offer any more details? Track conditions when it happened, max RPM, what were you doing at the time it blew(shifting, straight away, speed, etc), what oil is being used, video would be a bonus if you have that.

Can you pull the valve covers and make sure it didn't drop a valve?

 

[TMSBOSS]

Ouch

The Boss has had issues with detonation and lean conditions with 4&8.

91 Octane? 93 or better is recommended.

Without inspecting the engine, this is only poor speculation.

How to avoid in the future? Hard to say. A stronger bottom end like an aluminator is a good step.

 

[BKBoss302]

Track conditions were sunny and dry, 78F with low humidity, In 4th gear and about 6800-7000 rpm just about to go to 5th gear, straightaway at about 115mph, Motorcraft 5W-50. Have not pulled the valve covers yet but plan to next week. No indication this was going to happen. Car has run flawless up to this point.

 

[Grant 302]

Ford Track Key, 91 octane

This.

I’ve said a lot over the years about running at least a 93 octane equivalent with TracKey.

There’s enough audible ping 100% stock on CA 91 and the Red Key that I would never go to the track that way.

 

[302BOB]

Ouch is right!!!!!..That's a surprise nobody wants to go thru!!!...My Boss rarely sees speeds over 100MPH or RPM's over 6 grand, so hopefully I'll never have to experience that nightmare................Forgot to mention, my Boss has never been to a track...just to put this in perspective terms.............vid shows things going great in 4th on the straight and then boom!!.....the reason for that may never be discovered..................

 

[Dave_W]

Big props for the car control to keep from looping with oil-soaked rear tires. Is it a 2012 or 2013? Not sure if there were any engine differences between the years. I remember hearing talk of people losing #8 on the early Bama tunes, so that corner does seem more susceptible to knock and/or lean damage. And I believe the TracKey tune can run a bit leaner. I'd echo the recommendations for at least 93 on the red key. Some folks are augmenting with race gas, especially on hot days.

Wild theory time - how much gas was in the tank? Maybe some fuel starvation in the 180 turn to start the problem? Seemed like it was pulling okay out of the corner and not stumbling, though.

 

[Bill Pemberton]

Agree with Grant as it has been commented on by Engineers ( interestingly from Ford , GM and Chrysler ) that 93 Octane is what is likely best for quite few machines on track. Good recommendation from Grant , in my estimation, for all those who track performance machines.

Ref: This is the exact same recommendation Engineers at Dodge recommend for the Viper.

 

[302BOB]

93 Octane is what is likely best for quite few machines

Bill, All set for tomorrow???....Have fun and say Hi to everybody for me!!!....I can hear it now....Where's that dam Bus!!!.

 

[Mad Hatter]

Well I blew up my motor on my 4th track day this year. Does anyone have some insight as to why?
Here are the details:
Stock motor with 11,000 miles, no cats, X-pipe into Borla mufflers, washable air filter in stock airbox, Sebra 72 row oil cooler, fresh oil, Ford Track Key, 91 octane non-oxygenated gas
Number 8 piston is exploded and the rod with no cap on it is wedged in the area between the heads
Number 4 piston is still in the cylinder and 1/2 the rod is still connected to the crankshaft
Two big holes in the block on either side
Motor is still in the car until next week.
Bigger question - how do I prevent it from happening again?

View attachment 58601

Ouch... that looks bad! Sorry to see that, I know how you feel (twice for me)... .... nice driving controlling the car after!

Would strongly recommend getting a track tune from some one like Shaun at AED. Running the car with the ford tune, I imagine it is not set too run without the Cats and exhaust upgrades, so you were going lean already. Plus, as Grant says, the track key is on the lean side. That, and the 91 octane....... Ouch. Hope the heads are not too damaged. Best of luck!

Adding a big swig of race gas to the 93 would give you some extra protection at the track.

 

[TMSBOSS]

Like MH mentioned. 93 plus 100 racing gas is a good idea. I usually start the day with 5 gals plus of 100 then top off.

 

[302BOB]

The more the merrier (octane wise) may ring true here...............

 

[blacksheep-1]

The motors we ran in IMSA were only allowed a .020 overbore, ARP rod bolts and aftermarket valve springs, later on we were allowed an oil pump upgrade, and they were good for 50 hours. I would try to have a look at the top of those pistons and see if they are cratered due to detonation. Yes, at least 93 octane, as been said, the more the merrier with that.
I think Phoenix still has a Roush motor in the shop that needs freshening up, not sure what they want for it, prolly big $$, but all the good parts are in it.

 

[Mad Hatter]

The motors we ran in IMSA were only allowed a .020 overbore, ARP rod bolts and aftermarket valve springs, later on we were allowed an oil pump upgrade, and they were good for 50 hours. I would try to have a look at the top of those pistons and see if they are cratered due to detonation. Yes, at least 93 octane, as been said, the more the merrier with that.
I think Phoenix still has a Roush motor in the shop that needs freshening up, not sure what they want for it, prolly big $$, but all the good parts are in it.

I asked about that motor... they were fond of it, and at the time wanted to keep it, (pre covid). The did have some of those long blocks for gen1 use.

 

[Mad Hatter]

Too look on the bright side.... Every thing that breaks is a valid excuse for a upgrade when you pass it by the Board for approval of funds..... (THE significant other...).

At least that's what I say too my self all the time.

 

[Flyboygsxr]

Good save, could have been worse if you had hit the wall.

 

[BKBoss302]

Thanks everyone for the information and tips. A few follow up questions:
1. What is the best way to increase octane level in 91 -93 octane gas? Additives like VP Madditive or ? Mixed gas with a 100 octane racing fuel?
2. What do you think about no cats in this combination? Did that help or hurt this last motor or the next one? Is the flow rate of the exhaust creating a lean condition? Should I put the cats back in for the next replacement motor?
3. Should I continue to run the red track key with higher octane fuel or should I consider a custom tune or should I run the silver key on track days?

 

[PatientZero]

Thanks everyone for the information and tips. A few follow up questions:
1. What is the best way to increase octane level in 91 -93 octane gas? Additives like VP Madditive or ? Mixed gas with a 100 octane racing fuel?
2. What do you think about no cats in this combination? Did that help or hurt this last motor or the next one? Is the flow rate of the exhaust creating a lean condition? Should I put the cats back in for the next replacement motor?
3. Should I continue to run the red track key with higher octane fuel or should I consider a custom tune or should I run the silver key on track days?

Avoid additives, they don't work and likely cause more damage. Find 93 at the pump or mix your own. 7 gallons of 91 to 3 gallons of 100 will get you around 94 octane. You can Google octane mixture calculator.

 

[VoodooBoss]

Same thing happened to my 2012 Boss. I usually mixed 91 and 100 octane at the track. It’s cheap insurance. Yep mine still blew. My hole in the side of the crankcase on #8 looked very similar to yours. The back of my oil pan was blown out. Fortunately mine was covered under warranty. I also had a small fire but was quickly extinguished. Make sure everyone is carrying a fire extinguisher. Good luck with your rebuild.

 

[302 Hi Pro]

Should I continue to run the red track key with higher octane fuel or should I consider a custom tune or should I run the silver key on track days?

BKBoss:

My first thought is run a custom tune that requires you to Data log, or a Dyno tune so your Tuner can set up the proper fuel & timing tables to avoid a possible lean run condition and/or detonation (knock).

Looking back you ran the OEM TracKey with LTH’s & Cat deletes & no other intake mods except a drop in high flow air filter in the OEM air box. (Assuming same intake tube & 80mm TB). My question here is how did you account for the O2 sensor pcm data? Did you have any dash warning lights?

Just sorry to see you had such a catastrophic failure.