OMG! ConeDodger's Engine Case, is now ventilated Options

[McMark]

(IMG:style_emoticons/default/icon8.gif)

Rob just called me. Engine let go this morning in Stockton, on the way to the autocross.

(IMG:style_emoticons/default/sad.gif)

Sounds like a piston skirt broke off and trapped itself between the crank and case, and then blew its way out.

Now he's got to wait for a tow truck. Ooooooh man. Poor Rob.

I'm sure he'll have some pictures (with garbage cans) when he get's it back to his place.
(IMG:style_emoticons/default/hissyfit.gif) (IMG:style_emoticons/default/barf.gif)

[ghuff]

Detonation is fuel igniting when you do not want it to, pre-ignition. Some folks use the terms interchangably.

Basically, your crankshaft is moving up, your rod is moving up, and the charge ignites on a hot spot somewhere, this explosions creates a nasty pressure wave that is pushing back on the stuff as it is coming up.... That pressure wave plus the force of the rising piston/rod/etc is a LOT and too much for the motor to handle. Metal has it's limits.

Look at the broken rod above, the pistons in those motors will be fine to 650hp at the front wheels. That is the limit someone has reached. I have been driving on stock rods with 400hp, everyone tells me I should have thrown one. Well I have not because I am very anal about my tune.

Go look up how much force a piston/connecting rod is under as it's moving at 3000rpm.

This "pre-igniting" your mixture exerts loads on the metal that are way over normal combustion and etc.

(IMG:http://www.urbanracer.com/gallery/articles/techlab/2008/49/003.jpg)


Detonation can do that too, sometimes things do not always break. The type IV case looks thin though.

You can have inaudible light detonation that is slowly hammering away at your internals that only a knock sensor will pickup. You can also have total preignition that is blowing stuff apart due to the extreme force. This is why modern ECU's have knock sensors and retract timing. Sometimes you can't pull enough timing and bad gas is that, you end up with something like this. it's not black/white on/off there is inbetween with it.

I laugh again that there is someone who thinks because an air cooled once detonated, and they backed off that there is no way detonation can cause damage. That is mind blowingly stupid.

[J P Stein]

I laugh again that there is someone who thinks because an air cooled once detonated, and they backed off that there is no way detonation can cause damage. That is mind blowingly stupid.

Any of you are welcome to come play where I do & show me how much smarter you are than I. I'm reading a lot of words like "hate", "stupid", & "asshole"....the ass kissing smile was nice also. Too bad you clowns can't carry on a discussion without resorting to personal attacks.

The fact is that my engine did pre-ignite. Nothing broke and when I tore it down 7 years later, the piston tops, ring lands, rods & bearings showed no damage from that brief incident. Why piston tops you might ask?... because that is where detonation shows up most obviously. Rods can be bent from a few other causes and your pics show pistons in decent shape......they are whole for one and the tops aren't shown.

Here's a pic of the piston tops as removed from my engine....another after clean up. Nothing as trick as your T-4 pistons, but it was all I had. I noted that Robbie didn't show the tops of the pistons that survived his contretemps. His deduction that everything else is fine is simplistic....cause it ain't. There is crap all thru the oiling system.....but hay, what does a dummy like me know. Ya better ask Jake.

You laugh because ignorance is bliss it would seem.