Blown engine under 12K miles

[MeanMachine]

So driving up the highway I had a sudden loss of power, a shudder and barely got off the highway as the truck died. It had a piston blown through the block. I had it towed to my dealership to have him tell me "you're the second Gladiator we got this week with a piston through the block". Mine had 11K miles, the other had 7K miles. Hope this is isolated....

Just found out both trucks #4 piston rod blew the block - crazy!

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[cecaa850]

Just found out both trucks #4 piston rod blew the block - crazy!

Assembly line FUBAR. I'll bet the serial numbers are close to each other.

 

[ShadowsPapa]

Assembly line FUBAR. I'll bet the serial numbers are close to each other.

OR design issue.
Here's a good one - I can name at least 4, besides my own that is, so that would be 5, 1970 AMC 390s that blew #5 piston. The symptoms, the wreckage, indicates pretty clearly detonation.
But why #5 in each one of them?
In fact I've yet to see one that blew any other piston in that year engine. Some go fine with no issues, but some do number 5.
Further - my car had poor crankcase vacuum and with the oil fill cap off you could, if the light was JUST RIGHT, see a puff-puff-puff out the oil fill pipe. It had a touch over 24,000 miles on it - correct original miles verified by documentation and repair receipts.
When I tore it down I found something fascinating - this wasn't the first time #5 went on that engine.
It was bored .040 over to cover the prior damage but I could still see just a tiny tiny trace in the cylinder wall of the prior damage.
So the same engine blew #5 twice.
Most of us in the hobby, and mechanics as well (me being both) decided DESIGN FLAW - something about the cooling in that specific area of the block or heads - but if it was heads, why not an even-numbered cylinder since the heads fit either side - there's no left or right head (as with most engines of that era)
So something about the coolant flow was the most likely thing.
We found a way to machine a pattern into the head to prevent that damage by causing more turbulance in the cylinders and the problem, including ping in general, went away.

So, is there something about the head or block design, cooling system, etc.?
Or was it like another example I have where parts were incorrectly heat treated and it went unnoticed for a few weeks, resulting in valve train noise? That was a parts problem. Odd that the people putting things together didn't notice the lack of the blue color pattern indicating heat treating. But they didn't.

 

[cecaa850]

I would think that if it were a design issue we'd be seeing a bunch of these similar to the P0300 problem many are having. The fact that 2 were at the same store and no other reports makes me thing of assembly.

 

[AmishMike]

@RedTRex Looks like a cam plug, rear. Not sure on much more than that. Keep the mysteries coming, but maybe another thread for it.
Octane is a funny thing. Correct me if I am wrong but, the lower the number the higher the BTU's and therefore more energy. The higher numbers relate their resistance to pre-ignition so with higher numbers, you can run more timing and higher cylinder temps due to compression etc.. Ultimately, the lowest octane you can run without detonation should give you the most power.
If (old school non-computerized vehicle) you are experiencing a power increase with higher octane then you most likely have pre-detonation happening with the lower octane, but not audible, therefore robbing you of power. The higher the octane the less pre-ignition, so increase octane as long as power increases, get the octane too high and you will lose power due to loss of energy in the fuel ie. lower BTU's.
Think of alcohol vs. gasoline. Alcohol has much lower BTU's but you can subject it to crazy compression and timing and make tons of power while using about 80% more fuel to make up for the BTU loss.
Today's computerized systems get all confused with weird fuels and knock sensors etc. My wife's Subaru retards the timing so far with 87 octane that the car lags, we run 91 and it is great.
I bet, Hamburger's supercharger with bigger injectors and E-85 properly tuned would be fun and = broken drivetrain.
Oh, I miss 100 oct low-lead from the local airport.

 

[ShadowsPapa]

I would think that if it were a design issue we'd be seeing a bunch of these similar to the P0300 problem many are having. The fact that 2 were at the same store and no other reports makes me thing of assembly.

Good logic.
I don't know how the dealership orders for "on the lot samples" goes - but if like computers in the old days, if you placed an order for 10, you got sequential serial numbers. Does that work with cars/trucks? I don't know - but it WOULD fit your logic.

 

[ShadowsPapa]

@RedTRex Looks like a cam plug, rear. Not sure on much more than that. Keep the mysteries coming, but maybe another thread for it.
Octane is a funny thing. Correct me if I am wrong but, the lower the number the higher the BTU's and therefore more energy. The higher numbers relate their resistance to pre-ignition so with higher numbers, you can run more timing and higher cylinder temps due to compression etc.. Ultimately, the lowest octane you can run without detonation should give you the most power.
If (old school non-computerized vehicle) you are experiencing a power increase with higher octane then you most likely have pre-detonation happening with the lower octane, but not audible, therefore robbing you of power. The higher the octane the less pre-ignition, so increase octane as long as power increases, get the octane too high and you will lose power due to loss of energy in the fuel ie. lower BTU's.
Think of alcohol vs. gasoline. Alcohol has much lower BTU's but you can subject it to crazy compression and timing and make tons of power while using about 80% more fuel to make up for the BTU loss.
Today's computerized systems get all confused with weird fuels and knock sensors etc. My wife's Subaru retards the timing so far with 87 octane that the car lags, we run 91 and it is great.
I bet, Hamburger's supercharger with bigger injectors and E-85 properly tuned would be fun and = broken drivetrain.
Oh, I miss 100 oct low-lead from the local airport.

Nope - BTUs, talking straight gas here, does not change with octane. Octane has nothing at all to do with energy contained, BTUs, speed of the burn, etc.
It's ONLY resistance to self-ignition, that's it.
So if you run straight gasoline, NO ethanol at all and change from 87 to 89 - the BTU content would be the same.
The difference apllies only to ethanol, it's higher octane (resists self-ignition) but is lower BTU content. So if you throw in ethanol into the discussion, then yes, IF you boost octane with ethanol, then you would drop the BTU content somewhat - proportional to the percentage of ethanol.
Otherwise, and I studied this quite a bit in engine design for high performance, there is no BTU or energy difference, no change in how fast or how hot it burns, it's all in the longer chains that resist self-ignition.
You get the same BTU content.
I suppose this is another case where I could post all of my research files and do some scanning......

The higher the octane the less pre-ignition, ....

No again - it's not pre-ignition, that is totally different.
It is SELF-IGNITION, this happens AFTER the spark, so it's post ignition.
Pre-ignition is a different animal with a different cause. Pre-ignition is when the charge is fired before the spark - by hot carbon, spark plugs of the wrong heat range (too hot), cooling system issues causing hot spots and so on.

Octane deals only with self-ignition. Higher octane is longer chains which resist SELF-ignition, AFTER the spark.
The ping and damage from SELF-IGNITION, detonation, is caused when the flame front from the normal burning charge forces the unburned charge into a corner and raises the pressure so very high that it gets hot enough to ignite itself (like a diesel) Now you have the normal flame front advancing against the unburned charge that has just self-ignited and created it's own flame fromt. The two collide causing a sonic wave - ping sound - and it blows the barrier layer away from the piston top causing it to melt or BREAK from the extreme pressure and sonic wave.

Pre-ignition happens before the spark and octane will not deal with that at all because PRE-ignition is lit by an outside source, not pressures and the resulting heat.

Racing fuel is very high octane - and isn't lower in BTU content. It's because many of those engines are running very high compression. But racing engines also resist detonation because of the SPEED or RPM the engines are running. Detonation takes time, at 6,000+ RPM there isn't much time for detonation. (you won't drive some of these on the street for sure but then some of the came have a lower static compression and a much higher dynamic compression at RPM, so depending on the cam.....)

 

[cecaa850]

Good logic.
I don't know how the dealership orders for "on the lot samples" goes - but if like computers in the old days, if you placed an order for 10, you got sequential serial numbers. Does that work with cars/trucks? I don't know - but it WOULD fit your logic.

It's not uncommon for dealerships to get sequential VIN's.

 

[ShadowsPapa]

It's not uncommon for dealerships to get sequential VIN's.

I assumed as much....... it used to be that way, anyway. So that also fits this scenario.

 

[RedTRex]

I would think that if it were a design issue we'd be seeing a bunch of these similar to the P0300 problem many are having. The fact that 2 were at the same store and no other reports makes me thing of assembly.

Concur. 2 is just a lazy guy

 

[RedTRex]

@RedTRex Looks like a cam plug, rear. Not sure on much more than that. Keep the mysteries coming, but maybe another thread for it.
Octane is a funny thing. Correct me if I am wrong but, the lower the number the higher the BTU's and therefore more energy. The higher numbers relate their resistance to pre-ignition so with higher numbers, you can run more timing and higher cylinder temps due to compression etc.. Ultimately, the lowest octane you can run without detonation should give you the most power.
If (old school non-computerized vehicle) you are experiencing a power increase with higher octane then you most likely have pre-detonation happening with the lower octane, but not audible, therefore robbing you of power. The higher the octane the less pre-ignition, so increase octane as long as power increases, get the octane too high and you will lose power due to loss of energy in the fuel ie. lower BTU's.
Think of alcohol vs. gasoline. Alcohol has much lower BTU's but you can subject it to crazy compression and timing and make tons of power while using about 80% more fuel to make up for the BTU loss.
Today's computerized systems get all confused with weird fuels and knock sensors etc. My wife's Subaru retards the timing so far with 87 octane that the car lags, we run 91 and it is great.
I bet, Hamburger's supercharger with bigger injectors and E-85 properly tuned would be fun and = broken drivetrain.
Oh, I miss 100 oct low-lead from the local airport.

Correct- Small Block Chevy bell housing end. That pic was only up for like a day, good memory Mike....

 

[ShadowsPapa]

Correct- Small Block Chevy bell housing end. That pic was only up for like a day, good memory Mike....

That was easy for everyone - try some other area of the block, heads or transmission.........

 

[HONCHO]

sequential vin s maybe , but sequential engine serial numbers , not so much .

 

[RedTRex]

That was easy for everyone - try some other area of the block, heads or transmission.........

me thinks It may be difficult to stump Mr Wizard

 

[DAVECS1]

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