Bent Rod Pics..

[FullBlown]

So it seems like most of the time when failures happen, there is so much damage that it is hard to tell which part let go first.

Well, one of our friends from from Puerto Rico went to the track ,and this was the result of a 470hp and a bad tank of gas.

Our shortblock is going into this car now to ensure this won't happen again. He was very lucky to not have put a hole through it.

[Sportsguy83]

Originally Posted by FullBlown

Well, one of our friends from from Puerto Rico went to the track ,and this was the result of a 470hp and a bad tank of gas.

I have a mutual friend with Georgie and was told this story two days ago. Nice to see the pics.

@FullBlown I applaud the fact you guys are honest and transparent and put this kind of stuff out there. It benefits everyone and we all learn everyday what are the limits of this motor. I know for a fact Puerto Rico's gas is pure awful piss.

[post_break]

Can you explain this for the noobs. How did bad gas cause the rods to bend.

[SkullWorks]

"Bad gas" generally doesn't have the octane to support the desired fuel and timing conditions, this will lead to peak cylinder pressure happening when the crankshaft is not yet past top dead center so the piston is still coming up in the bore. whatever is weakest bends or breaks, because you are pushing with great force on both sides of the piston.

The above description is what you would call pre-ignition or detonation or knock, depending on what exact circumstances lead to the "bad combustion event".

I hope that is some what non-confusing.

[SmsAlSuwaidi]

Bad gas ( maybe water in it ?) caused a hydrolock ?

[SmsAlSuwaidi]

Originally Posted by SkullWorks

"Bad gas" generally doesn't have the octane to support the desired fuel and timing conditions, this will lead to peak cylinder pressure happening when the crankshaft is not yet past top dead center so the piston is still coming up in the bore. whatever is weakest bends or breaks, because you are pushing with great force on both sides of the piston.

The above description is what you would call pre-ignition or detonation or knock, depending on what exact circumstances lead to the "bad combustion event".

I hope that is some what non-confusing.

Doesn't detonation usually affect top of the stroke and less strain/force on the sides ?
@FullBlown ?

[FullBlown]

Originally Posted by post_break

Can you explain this for the noobs. How did bad gas cause the rods to bend.

Detonation/ preignition from low quality fuel or too much ignition advance will cause rods to bend/break. Not only that, but it can beat up the bearings and ruin other things as well.

[rice_classic]

Originally Posted by SkullWorks

"Bad gas" generally doesn't have the octane to support the desired fuel and timing conditions, this will lead to peak cylinder pressure happening when the crankshaft is not yet past top dead center so the piston is still coming up in the bore. whatever is weakest bends or breaks, because you are pushing with great force on both sides of the piston.

The above description is what you would call pre-ignition or detonation or knock, depending on what exact circumstances lead to the "bad combustion event".

knock and ping are not the same as pre-ignition. What you're describing above is pre-ignition when the combustion takes place, in full, way too early pushing against the piston while it's still traveling upwards.

Ping or Knock is the result of an uncontrolled burn. Where the heat and compression begins to ignite part of the air/fuel mixture (usually around the edges of the piston) and the spark ignites the other part. It's essentially the meeting of 2 separate flame fronts that cause the full ignition to occur outside of the optimal timing. This meeting of flame front causes a massive spike in heat and cylinder pressure which creates a shockwave at a high frequency that we hear as a ping or knock. Like metal balls in a coffee can.

Pinging/Knocking is generally not the cause of rods bending (that would be pre-det), it's the cause of pistons melting, valves burning, ring lands cracking or engines overheating. What's funny is the user manual in my Econoline Van says that occasional pinging is "normal and to be expected" which I found odd. I guess that's the difference between a cast iron engine and aluminum one.

Pinging/knocking:

Note: Pinging is not an explosion it is merely a very fast combustion, which exceeds the healthy limits. The propagation of an explosion's pressure wave would be far higher,
something like 2000m/s. (m/s = metres per second)

edit: forgot to add this:

[slowmo]

are those stock rods ?

[FullBlown]

Originally Posted by slowmo

are those stock rods ?

Yes they are

[SkullWorks]

Originally Posted by rice_classic

knock and ping are not the same as pre-ignition. What you're describing above is pre-ignition when the combustion takes place, in full, way too early pushing against the piston while it's still traveling upwards.

Ping or Knock is the result of an uncontrolled burn. Where the heat and compression begins to ignite part of the air/fuel mixture (usually around the edges of the piston) and the spark ignites the other part. It's essentially the meeting of 2 separate flame fronts that cause the full ignition to occur outside of the optimal timing. This meeting of flame front causes a massive spike in heat and cylinder pressure which creates a shockwave at a high frequency that we hear as a ping or knock. Like metal balls in a coffee can.

Pinging/Knocking is generally not the cause of rods bending (that would be pre-det), it's the cause of pistons melting, valves burning, ring lands cracking or engines overheating. What's funny is the user manual in my Econoline Van says that occasional pinging is "normal and to be expected" which I found odd. I guess that's the difference between a cast iron engine and aluminum one.

Pinging/knocking:






edit: forgot to add this:

I didn't go into full detail because a noob answer was required. It is easy to lay out the differences in text but the reality of the situation is all of these events are very closely tied and often happen concurrently with one another, Knock is an audible noise, it doesn't designate, when described in text, what occurred internal to the combustion chamber. Pinging is much the same, a description of the audible results of bad combustion. Pre-ignition describes a combustion event that occurs before desired, (generally ~14 degreees ATDC is when you want peak cylinder pressure)

Detonation describes the event that generally immediately follows...because now you have fuel burning and pressure building from 2 sources...1 mechanical 2 thermal...

detonation alone is just a slower death,

it's akin to the all squares are rectangles but not all rectangles are squares statement.....if you can hear it, it's knock (or pinging) which means it is a rectangle, but not necessarily a square, if it bends a rod it is most assuredly a square...which also happens to be a rectangle...

[Floggin Tires]

▲

[MightyMeeple]

it's akin to the all squares are rectangles but not all rectangles are squares statement.....if you can hear it, it's knock (or pinging) which means it is a rectangle, but not necessarily a square, if it bends a rod it is most assuredly a square...which also happens to be a rectangle...

[Circuit Motorsports]

Oh my....

Do they get E85 in PR?