Why did this happen? (pics)

[unlikely hero]

Well I was racing a 04 cobra top end and like 10 minutes later engine shut down. Took the oilpan off and found #4 piston(closest to tranny) in about 100 pieces and this bent rod. Also the rod was lose on the crank as well. Anyone have an idea of what happened?
=Jason-

 

[blue92laser]

Alright I think I have your answer as too why all this happened. I am going to start off by saying...weather or not its a 6lb deduction in rotateing force, it is not good to remove any balance shafts. They were definately put in the motor for a reason and that reason wasnt too remove them. They balance out the engine vibrations and everyone on here is removing them like they don't do anything. Personally I left mine in. I don't like the vibrations and the sounds you here definately do no justtice what the engine is actually going through vibrating like that.

I would also like to say that is probably why you lost an oil squirter and you bent something. Well its a reason that you could use. Remember this guy was RACING his car and when you race, things go wrong and the car is bound to break beating on it. It to mee looks like some definate mass detonation and I would have to say it came from the engine not having balance shafts.

I would like to back this up by using the harmonic balancer as an example. Everyone tries to put underdrive pullies and lightend crank pullies and such without even knowing the actual purpose for the harmonic balancer. Well, the balancer absorbs rotational crank vibrations (this means that the crank with all of the pressure and power being made, the crank itself is bending and distorting) the balancer absorbs those vibrations and movements and in a way reduces it from happening. This is very bad to remove beause of the dangers of these 4 cyl. in higher RPM's. There is just more and more damage being done to evedrything while that balancer is off and in time, probably 10k miles or so, the motor will begin to fall apart. Or violently break.

I can tie this in with the balancer because the balance shafts not only quiet down the uneven balance of the engine as it is firing, it stops the vibrations alltogether. Less vibrations make so the knock sensor doesnt pick anything up, so it doesnt retard timing up top @ WOT and doesnt cause your engine to bend rods or break off oil squirters or vibrate to peices violently while destroying the block.

Well, this is only my .02 cents.

 

[turbodagain]

UMM the balance shafts do not have anything to do with the balance of the crank. The are to cancel out external [no, internal] vibrations. They are not even conected to the crank. Read up more about it...