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The oaf-ish-ul "why ecoboost goes boom" thread

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Robert Culbertson
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 24, 2016 02:57AM
Not another motor. 2 motors total, both with the exact same results... holes in pistons.
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Pete
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 24, 2016 04:54AM
Thermally isolate those air temp senders from the tubes.



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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 07:36AM
Quote
Robert Culbertson
Stay tuned for pictures of carnage and destruction!

Such a tease!!!!

What is the current theory? Did the other cylinders show signs of detonation? How do those spark plug ground straps look?
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Robert Culbertson
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 11:08AM
Quote
MarkHille
Quote
Robert Culbertson
Stay tuned for pictures of carnage and destruction!

Such a tease!!!!

What is the current theory? Did the other cylinders show signs of detonation? How do those spark plug ground straps look?

I know right?!?!

The other cylinders showed holes in all of the pistons on one motor, and holes in 2 pistons on another.
There are just a few signs of detonation...



Edited 1 time(s). Last edit at 11/30/2016 11:08AM by Robert Culbertson.
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 11:15AM
could it be that Ford just used shitty pistons?



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Robert Culbertson
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 12:08PM
Finally uploaded some pictures.
Here's the pistons from motor #1 (low miles, overheated a bunch of times, made it an entire season and then some).
They all basically look like this.



The head for engine #1 has ZERO signs of detonation.

Engine #2 (30k mile junkyard motor, made it through Idaho, DooWops, and recce of Rocky)




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Robert Culbertson
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 12:14PM
Quote
Gravity Fed
could it be that Ford just used shitty pistons?

Could be. They are apparently forged, but I haven't pulled them out of the block to check the undersides. The fact that the pistons "eroded" instead of shattered leads me to believe they are forged. Probably a higher silica content forging, making them less tough.

We know that the charge temps were high, and it was going into limp mode. Apparently resetting the ECU lets you drive through that.... and straight into destroyed pistons.

Ford also offers a calibration for the ECU that dumps a ton more fuel. We only found out about this after talking with a powertrain engineer at Ford Performance a few weeks ago. They use the tune for desert trucks/buggies that are using the engine. Glad it's a free re-flash, I just wish we would have known about it sooner.
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 01:30PM
Quote
Gravity Fed
could it be that Ford just used shitty pistons?

I don't think detonation is sustainable no matter how much money you spend on pistons. Better pistons will be more forgiving and give you a little more buffer but it doesn't sound like that is the solution to the problem.

Those marks on the piston/head.....there are some pistons with marks (dings not detonation) that look like they weren't self induced. Like there aren't any bits big enough broken off to cause the damage. Were piston bits from the one cylinder traveling to the other cylinders or was there foreign contamination? How is your turbo looking?

I would check to see what octane fuel the desert trucks/buggies are running. I would be very, very, very surprised if adding fuel and not taking some timing out (or lowering boost) was the end all be all solution to your problems. I don't think your current tune (or your current octane, whichever way you want to look at it) is close enough for just that. smileys with beer
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Robert Culbertson
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 01:53PM
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MarkHille


Those marks on the piston/head.....there are some pistons with marks (dings not detonation) that look like they weren't self induced. Like there aren't any bits big enough broken off to cause the damage. Were piston bits from the one cylinder traveling to the other cylinders or was there foreign contamination? How is your turbo looking?

The marks, we'll call them dents, definitely look like foreign matter. The heads and pistons with the dents came from the high mileage junkyard motor. So the dents are found on the quench pads of every combustion chamber, even the ones with pistons with just a little bit of detonation erosion. The turbo looks fine, and there was no foreign material in the intake manifold or any of the plumbing. Maybe they were already there when we picked up the motor...?!

Quote
MarkHille
I would check to see what octane fuel the desert trucks/buggies are running. I would be very, very, very surprised if adding fuel and not taking some timing out (or lowering boost) was the end all be all solution to your problems. I don't think your current tune (or your current octane, whichever way you want to look at it) is close enough for just that. smileys with beer

I need to talk with the guy at Ford about the differences in the tunes and what fuel the trucks are running. I fully agree that pulling timing is going to be much better at keeping the motors happy.
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 03:57PM
Looks like a LOT of heat got into those pistons...note the baked on carbon at the broken edges. Probably more a fuel shortage issue, though if the ECU pulls too much timing with plenty of fuel in the mix, it basically makes a blowtorch.

Chances are the dents in the chambers are from the melted piston bits. There's enough plenum sharing it's not uncommon for one cylinder to feed all the others with those little bits of metal.

I'd see what the reflash does for the engine, but I'd also seriously consider an air/fuel gauge and an EGT gauge to monitor what's going on there under rally conditions.



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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 04:39PM
I don't quite understand why the tune is "bad". From the factory, these motors make great, safe power. What so different here?
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
November 30, 2016 11:05PM
Quote
Ascona73
Looks like a LOT of heat got into those pistons...note the baked on carbon at the broken edges. Probably more a fuel shortage issue, though if the ECU pulls too much timing with plenty of fuel in the mix, it basically makes a blowtorch.

This is why I keep going on about the air temp sensors. The fact that they went out of bounds according to the PCM is a clue. If the sensors are getting artificially heated up by hot tubing instead of reading the true air temperature, the computer will be sending fuel for a much less dense charge, or in other words, insufficient fuel.

Or it could just be that the rings had not enough gap, and when they got hot under SUSTAINED loads much higher than the engines were built for, they butted and popped the OE style low-crevice-volume pistons' heads apart. The OE tune is conservative for Joe Average who will bolt the throttle to the floor climbing a mountain etc etc. The Motorsport tune gets all that fat midrange by taking away some of that idiot-proofing, with the side result that the nut holding the wheel is more responsible for engine health.

Since it is probably impossible to find pistons with the correct bowl/dish shapes and a lower ringpack, it may be wise to just open the ring gap a skosh on the next junkyard mill and try again. Winter's coming, lots of people are going to be totaling their Escapes...

Unbolt the rods and carefully pop the pistons out so you can spiral the rings out and take a real close look at the ends. That is where you'll see if the rings were butting or not, if the ends are shiny or peened-looking then there's one thing you can fix.



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Edited 2 time(s). Last edit at 11/30/2016 11:13PM by Pete.
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john vanlandingham
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
December 01, 2016 01:48AM
Quote
dreamsofjvl
I don't quite understand why the tune is "bad". From the factory, these motors make great, safe power. What so different here?

Greed?
Poor advice?
Inexperience?
American fixation with MOAR POWERZ...?
Because we can?



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Re: The oaf-ish-ul "why ecoboost goes boom" thread
December 01, 2016 08:11AM
I'm bored so here goes....

It is possible that the only reason engine damage occurred was because the intercooler setup was inadequate and this caused unsustainably high intake air temperatures. The ECU tried to prevent engine damage by going into limp mode (lower boost, pulled timing, and possibly more fuel, maybe even less spark events) but was then shut off causing it to reset in which case it returned to normal operation and continued to damage the engine by causing detonation. This is possible....but it seems a little unlikely. Why wouldn't it go into limp mode again immediately?

There are 2 types of air sensors for the lima. A metal one and a plastic one. I have used both and have used them in both aluminum pipe and silicone pipe both pre and post intercooler. There was no difference in performance that I could tell and I was logging the temps to see. The sensors only got heat soaked when the car was off. When the motor was started there was only a couple of seconds that it read hot and then everything went to normal.....unless the position is total crap or the sensor is not working I don't think this is the only cause of the problem.

It is only my personal opinion but I would be willing to bet that if you had been running 110 octane race fuel both motors would still be running. The tune isn't crap. The tune was developed by Ford who has a shit ton of resources. The Motorsports tune is probably partially based off of the production tune and both probably had hours and hours and $$$$$ and $$$$$ to develop them. But, like Pete said, you get more power by sacrificing the safety buffer inching closer and closer to detonation and engine failure. All of that testing is based specifically off fuel octane. If the tune is developed for a certain octane, and you run a lower octane, you are going to detonate the motor and it is going to blow up. PERIOD.

A safe AFR for a turbo car is around 11:1 to 12.5:1? It isn't so hard to get in that range. Yes you can make more power with a little more or a little less depending on your setup but if you lean it out and it starts to detonate you aren't making shit for power. I personally would never run a turbo car without a wide band. I like to know things are where they are supposed to be and if I have a problem I like to be able to look over and see that AFR isn't the cause. I'm sure there are others like me who are running the Ford motorsports ECU and if it was super lean they would know about it and be shouting it from the hills...maybe not. I would bet more on low fuel pressure from a mechanical problem than on ford being too lean. Easy and fairly cheap way to find out.

There is only so much power available in the AFR. Way more power exists in the boost and in the timing. I doubt Ford is trying to make it up in the AFR. The only real variables are the engine temp and the intake air temp. If they go too high the ECU would need to compensate by adding fuel and pulling timing. This is going off of memory but the rate timing gets pulled is only like 1 degree for every 50 degrees F above 200 or something like that. I don't think we are talking about pulling 10 degrees of timing when the intake air is too hot but maybe I'm wrong. The problem with a hot motor and hot intake air is PREIGNITION. The fuel starts to burn before the spark and basically leads to the same demise. Pre-ignition can be caused by a hot piston...a piston that has sharp edges on it that has formed a hot spot...a piston with dings in it like the ones pictured above. It is possible those sharp edges were causing pre-ignition but if they came after the piston broke and not before it broke it isn't the cause of the main problem, detonation is. What is the easiest way to prevent detonation (or pre-ignition) on an engine that is running proper timing? More octane. You might not make more power but your safety buffer just got a whole lot bigger. thumbs up smiley
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Pete
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Re: The oaf-ish-ul "why ecoboost goes boom" thread
December 01, 2016 07:41PM
Quote
john vanlandingham
Quote
dreamsofjvl
I don't quite understand why the tune is "bad". From the factory, these motors make great, safe power. What so different here?

Greed?
Poor advice?
Inexperience?
American fixation with MOAR POWERZ...?
Because we can?

The tunes in question come straight from Ford, I think.



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Silence is golden, but duct tape is silver.
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