The Autopsy Results.....OUCH!!

[Marauderjack]

As expected #7 piston lost part of the top ring land but from the looks in this photo a BIGGER piece than I thought!!:eek:

Steve said it beat the valves up pretty good and they will be replaced too!!:cool:

The motor actually looks pretty clean to me for the miles!!;)

Stay tuned!!

[screamn]

As expected #7 piston lost part of the top ring land but from the looks in this photo a BIGGER piece than I thought!!:eek:

Steve said it beat the valves up pretty good and they will be replaced too!!:cool:

The motor actually looks pretty clean to me for the miles!!;)

Stay tuned!!

Would the cooling mod have help prevent this or do you already have it installed?

I'm interested in doing this mod to my motor but still contemplating....

[Marauderjack]

I don't think so but it couldn't hurt to do it if you want to!!:shake:

This motor has stayed together waaaaay longer than I ever thought it would cooling mod or not!!:beer:

BTW, we are not doing it on the rebuild as far as I know but I'll ask the builder to see what he thinks!!;)

[burt ragio]

So do you have any plans for any special goodies ?

[8UWITH6]

I may not have read your reply correctly but does your car have the cooling mod Jack? If so how long has it been on the car. Thanks.

BTW, ouchie, glad you fixy!

[Jeffonebuck]

With that many miles it was probably most in part caused by fatigue.


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[Marauderjack]

I may not have read your reply correctly but does your car have the cooling mod Jack? If so how long has it been on the car. Thanks.

BTW, ouchie, glad you fixy!


No sir....no cooling mod!!:shake:

[Marauderjack]

With that many miles it was probably most in part caused by fatigue.


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I certainly agree with the age and grief the motor has endured!!:cool:

There is a true "FORD GUY" with an unbelievable wealth of experience and knowledge out in Washington state!! Below is his explanation of this event:

Bummer! But the pistons were not the problem. So, look at the up-side, that a standard replacement drop-in will be fine for another zillion miles. There are two indicators in your photo pointing to the cause of the failure. First is the obvious chunk of top land missing. There is one cause of this - ring butting - and has no bearing on the type of piston used. The next question is why the ring got so hot that it expanded to the point of butting ends, seizing in the bore, and ripping the chunk out on the down-stroke.

While ring gaps too small can do this with the higher heat of higher HP, it didn't do it until now, so there must be a second cause. Sure enough, it appears there is freckling on the piston top, indicating mild detonation. So, for those reading that are unfamiliar with failure diagnosis, let's follow the sequence that leads to missing a piece of piston, and the cause of the cause of the cause.

While not powerful enough to do damage itself, the effect of mild det is to blast the thin barrier layer of air that clings to and protects the piston from direct heat. Without this boundary layer, the piston rapidly heats, and where does piston heat go? The rings. The rings expand with the greater heat, and if they don't have enough ring gap to expand, the ends of the top ring butt against each other. With nowhere left to expand, they begin to push outwards with great force, seizing in the cylinder bore. With the ring stuck but the rod pulling the piston down, something has to give, and the top ring land shears off. Under these conditions, what the piston is made of makes no difference.

So, what we need to know now is why it had detonation to cause all this. The most common reasons are insufficient octane (old/bad batch or mis-labeled fuel), excessive timing advance, lean fuel/air mixture, engine over-temperature (overheat or accumulated heat from a long power pull), carbon buildup, or wrong spark plug heat range. Usually, it's a combination of two or more of these, and there are other possible causes. The primary job now is determining those causes and repairing the issue to avoid a repeat. Note that the fact this engine is supercharged is not a contributor, as a normally-aspirated engine would do the same thing, under the same load conditions.

Jack - are you going for a stock rebuild or building for more power/rpm this time?

David

At this point I suspect bad gas/low octane for a couple stooooopid reasons and the screw up will NOT have a chance to happen again!! NO Dom, it was not Kerosene!!:shake:

[Jeffonebuck]

"So", It was a combination of Bad Gas and Old Age, ,!! :burnout:


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[Marauderjack]

"So", It was a combination of Bad Gas and Old Age, ,!! :burnout:


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DAMN....that sounds like a description of ME!!:eek:

[Jeffonebuck]

DAMN....that sounds like a description of ME!!:eek:


Maybe I know a little about this myself. :alone: thanks for the laugh, Happy Thanksgiving


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[Marauderman]

As expected #7 piston lost part of the top ring land but from the looks in this photo a BIGGER piece than I thought!!:eek:

Steve said it beat the valves up pretty good and they will be replaced too!!:cool:

The motor actually looks pretty clean to me for the miles!!;)

Stay tuned!!

Exactly what happen to me---believed someone called it --"blowing the lancer ring/s" went out my pipes and the piston pushed up the #7 plug thru ---yep--still got the piston for a table weight in the garage work bench--- dang engine sounded like open headers till I got it home ---that's when I did my rebuild---

[Marauderjack]

Hey Tom......where did the piece of piston go.....on the catalyst and burn up??:eek:

Here are some more photos of the engine removal and tear down!!:help:

[sailsmen]

J. B. Weld!!!

[Marauderjack]

J. B. Weld!!!

Thought about that Billy but it's only good to about 600*F....plus we cannot find the piston piece to glue back in!!:confused:

[8UWITH6]

Sounds like your on the right track. Double and triple check your fuel system and ignition system. Put the new bullet in and let her rip again. :)

[PHHHHTT]

After reading the description that MarauderJack posted regarding detonation, I began to wonder if there is a gauge or indicator that will someone a visual sign when detonation is occurring. I googled "engine detonation gauge" just to see if this device exist.
Google returned responses that list Summit as to having a Casper Knock gauge and another listing regarding a "KnockBlock" that can be used to assist engine tuning and supplies a light that can viewed by the driver to alert that detonation is occurring.

Has anyone here had experience with items such as these? If they work, sounds like a good thing to have. I suppose most people would not know if their last fill up of fuel was a good batch or bad unless conditions indicated such. By the time a person realizes this, the engine could have suffered quite a while.

[Marauderjack]

After reading the description that MarauderJack posted regarding detonation, I began to wonder if there is a gauge or indicator that will someone a visual sign when detonation is occurring. I googled "engine detonation gauge" just to see if this device exist.
Google returned responses that list Summit as to having a Casper Knock gauge and another listing regarding a "KnockBlock" that can be used to assist engine tuning and supplies a light that can viewed by the driver to alert that detonation is occurring.

Has anyone here had experience with items such as these? If they work, sounds like a good thing to have. I suppose most people would not know if their last fill up of fuel was a good batch or bad unless conditions indicated such. By the time a person realizes this, the engine could have suffered quite a while.

The best defense it a good offense....I'm sure you have heard this!!;)

My tune was conservative but I think the timing was adjusted for 93 octane...perhaps dangerous since fuel looses octane fairly rapidly??:argue:

I am going with a 91 octane tune with the new motor guts and buy ONLY from a reliable source when I can (Shell)...no more discount gas unless absolutely necessary...then drive it easy (right??).....probably not!!:D

We are all vulnerable to fuel delivery mistakes and some station owners may even "mix" higher octane tanks on purpose.....I probably got some old gas or maybe a mixture of 89 and 94...I don't know but I'm asking our State Regulators to check this station......if the octane is low on the 94 I may pursue compensation...we'll see??:argue: 95% of the 94 octane buyers probably use it in cars setup to run 87 octane thinking they are doing better for their cars so a slug of lower octane would not hurt and would actually help them!!:confused:

Tuning for "max power" is very dangerous unless you are absolutely sure of the fuel you are using!!:cool:

[Marauderman]

Hey Tom......where did the piece of piston go.....on the catalyst and burn up??:eek:

Here are some more photos of the engine removal and tear down!!:help:

Never did find that piece--but it wasn't as big a piece as yours---mine was about quarter size of yours that is missing...will try a get a pic FWIW....

My rebuild re-coned my pistons tops to where they were curved and not squared that came OEM

[MERCULES]

Does anyone recommend an octane boost additive each time you fill up?

Can too much octane be a problem, I have a Lidio tune and drive it stiff but I don't trust the fuel when purchased as you never really no for sure.
:confused:

[whitey]

Does anyone recommend an octane boost additive each time you fill up?

Can too much octane be a problem, I have a Lidio tune and drive it stiff but I don't trust the fuel when purchased as you never really no for sure.
:confused:

Octane boosters in the store dont do anything but raise octane a few points(10 points per octane number) I would recommend mixing in a race gas with a higher octane. Too much octane can foul plugs, and leave lots of carbon deposits behind, also it will make your wallet lighter. Unless tuned for a higher octane than 93, running a 104 octane will do nothing.

[RF Overlord]

Does anyone recommend an octane boost additive each time you fill up?Absolutely not.

When the average OTC octane "booster" says it raises the octane by 4-7 "points", what they are really referring to is 4-7 TENTHS of an octane rating. IOW, it will raise 91 octane to 91.4 - 91.7. Not enough to be useful, plus the chemicals used create valve and spark plug deposits.


Can too much octane be a problem,Not a problem, per se, but using fuel with a higher octane rating than needed buys you nothing. If you have a tune or other modifications which make higher than 91 needed, then of course you should use it, but otherwise it's just money out the tailpipe.

*I see whitey beat me to it...*

[Jeronimojc]

Marauderjack, may I ask how much boost / timing this setup had ?


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[MERCULES]

Whitey and RF Overlord, thanks for the info, happy thanksgiving to you and your crew. :beer:

[sailsmen]

Does anyone recommend an octane boost additive each time you fill up?

Can too much octane be a problem, I have a Lidio tune and drive it stiff but I don't trust the fuel when purchased as you never really no for sure.
:confused:

The Volvo Club of NA ran a test on several octane boosters. Lucas was by far the best raising the octane significantly. I have used when I was at the track and could not easily get race fuel.

I would not use it on a regular basis for the reasons stated. If you need higher octane look into a 50/50 meth system.

[Marauderjack]

Marauderjack, may I ask how much boost / timing this setup had ?


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Not sure on timing but in cool weather it would make 11 PSI but normal was around 9 PSI!!:beer:

That fateful day it was VERY STRONG which leads me to believe lower octane could be the culprit!!:burnout:

[lifespeed]

Typically an engine build that will see supercharging will have the top ring gapped 0.002" larger than for a naturally aspirated engine. And there is always the gapless ring option, which is actually able to accommodate more expansion because of the overlapping ends. So this is another one of those areas where a purpose-built bottom end has an advantage over stock.

That said, paying close attention to tune, fuel and the possibility of detonation remains very important.

[Marauderjack]

I was cleaning up 2 of the piston/rod assemblies for gag gifts and LOOK WHAT I FOUND.....YIKES!!:eek: :confused:

Wonder how many more are damaged??:(

Stay Tuned!!:cool:

[8UWITH6]

If you want to splash the tank with a little race gas to suppress detonation there is nothing wrong with that. If you are running on the ragged edge on a pump gas tune I would suggest it. Otherwise just lower the timing down for 91 octane and motor on down the road.

[chief455]

While not powerful enough to do damage itself, the effect of mild det is to blast the thin barrier layer of air that clings to and protects the piston from direct heat. Without this boundary layer, the piston rapidly heats, and where does piston heat go? The rings. The rings expand with the greater heat, and if they don't have enough ring gap to expand, the ends of the top ring butt against each other. With nowhere left to expand, they begin to push outwards with great force, seizing in the cylinder bore. With the ring stuck but the rod pulling the piston down, something has to give, and the top ring land shears off. Under these conditions, what the piston is made of makes no difference.

So, what we need to know now is why it had detonation to cause all this. The most common reasons are insufficient octane (old/bad batch or mis-labeled fuel), excessive timing advance, lean fuel/air mixture, engine over-temperature (overheat or accumulated heat from a long power pull), carbon buildup, or wrong spark plug heat range. Usually, it's a combination of two or more of these, and there are other possible causes. The primary job now is determining those causes and repairing the issue to avoid a repeat. Note that the fact this engine is supercharged is not a contributor, as a normally-aspirated engine would do the same thing, under the same load conditions.


One of the best written explainations I've read.
It has happened to me, and how / why is in the words above.
You have a smart engine builder ;)

[Zack]

If you keep the max timing to 13 or under on a stock engine, it will live forever.
(Unless a pump or other extreme factor is to blame)

[Marauderjack]

If you want to splash the tank with a little race gas to suppress detonation there is nothing wrong with that. If you are running on the ragged edge on a pump gas tune I would suggest it. Otherwise just lower the timing down for 91 octane and motor on down the road.

It was setup for 91 Octane and lived 174K miles before this so I truly suspect a bad load of gas.......working on that with the seller!!:argue:

Shell 93 from now on.......never had a hint of trouble with Shell fuel!!:beer::bows:

[fastblackmerc]

I was cleaning up 2 of the piston/rod assemblies for gag gifts and LOOK WHAT I FOUND.....YIKES!!:eek: :confused:

Wonder how many more are damaged??:(

Stay Tuned!!:cool:

A little dab of JB Weld and they are good as new!

[Marauderjack]

Closer investigation revealed another BROKEN piston so my #7 & #8 theory is shot!!:shake:

Wonder which ones the other two are since they both have 2nd lands broken while #7 has the top land broken.....ideas??:confused:

BTW.....they all seem to be broken on the "thrust" side.....right??:confused:

[Marauderjack]

A little dab of JB Weld and they are good as new!

I'll send 'em to you to JB Weld.....if you will GUARANTEE they will last forever Jim!!;)

[lifespeed]

Note that the fact this engine is supercharged is not a contributor, as a normally-aspirated engine would do the same thing, under the same load conditions.


One of the best written explainations I've read.
It has happened to me, and how / why is in the words above.
You have a smart engine builder ;)

An excellent analysis, except for the comment on supercharging. It is widely recognized that supercharging increases cylinder pressures and temperatures. How else would you get more power?

An experienced engine builder will increase the ring gap to accommodate the added heat from a supercharged engine. An OEM concerned with naturally-aspirated power and efficiency will set the gap appropriately smaller. This appears to be at odds with the above statement.

I doubt that all those pistons broke during a single incident of low octane. The problem, whether it was too much timing for the fuel/boost combination, too much heat for the ring gap, or a combination of the above was, IMHO, present for some time.

[RF Overlord]

Holy Moley, 'jack...looks like you had a 5-cylinder car there for a while....

[chief455]

An excellent analysis, except for the comment on supercharging. It is widely recognized that supercharging increases cylinder pressures and temperatures. How else would you get more power?

An experienced engine builder will increase the ring gap to accommodate the added heat from a supercharged engine. An OEM concerned with naturally-aspirated power and efficiency will set the gap appropriately smaller. This appears to be at odds with the above statement.

I doubt that all those pistons broke during a single incident of low octane. The problem, whether it was too much timing for the fuel/boost combination, too much heat for the ring gap, or a combination of the above was, IMHO, present for some time.
I think his comment on supercharging was meant to keep focus on the root causes. Yes, forced induction adds heat / pressure, but the incorrect air / fuel, timing, etc root causes remain the same, n/a or forced induction.
I agree this much damage likely happened over a period, however short, of time. Maybe an entire tank run of total garbage fuel, detonating all the way:depress:
I lost 6 JE forged blower pistons, 8.5:1, conservative tune, due to fuel starvation when the in tank pump was falling off.:eek:

[justbob]

A detonation in one cylinder could easily carry into all others simply by harmonics. Besides, if it's detonating from fuel quality, it's detonating in all cylinders or at minimal the hottest ones.


Builder Of Badassery

[Zack]

All broken pistons pictured will (and would have) made close to 100% compeession

[chief455]

All broken pistons pictured will (and would have) made close to 100% compression
Thus the engine runs so strong when the damage is being done. I know mine was. It was tuned rich at WOT to keep the chamber cooler, so when the fuel starved, it went leaner, made more power and felt great! So I drove it hard :rolleyes:
Wish I knew than what that 7 grand rebuild cost and made me understand now. Have an air/fuel gauge and watch it. Have a fuel pressure gauge reading after the injectors on return, and watch it closely for sudden drops. Have your computer sense knock (or assume it) and pull timing if it does.

[Marauderjack]

Holy Moley, 'jack...looks like you had a 5-cylinder car there for a while....

Only #7 misfired Bob......the other 2 were not even visible until cleaning resulted in the 2nd land piece just falling out!!:confused:

BTW.....when I started it to back it off the trailer it ran PERFECTLY!!:eek:

[Marauderjack]

All broken pistons pictured will (and would have) made close to 100% compeession

It ran fine after the top land debris was ejected.......almost put it back on the trailer to take it home.......NAW!!:shake:

[Marauderjack]

Thus the engine runs so strong when the damage is being done. I know mine was. It was tuned rich at WOT to keep the chamber cooler, so when the fuel starved, it went leaner, made more power and felt great! So I drove it hard :rolleyes:
Wish I knew than what that 7 grand rebuild cost and made me understand now. Have an air/fuel gauge and watch it. Have a fuel pressure gauge reading after the injectors on return, and watch it closely for sudden drops. Have your computer sense knock (or assume it) and pull timing if it does.

During the last "hard launch" it was crazy strong.....I had to get off the throttle a little to guarantee control.....just a little but it was too late!!:argue:

I am in contact with the fuel supplier.......probably no help but we'll see??:confused:

I suspect someone dropped the wrong gas in the "93 Hole" and I was the only "lucky" one.......most people waste $$$'s running high octane thinking they get more power!!:shake:

[martyo]

The lawyer in me says that if the fuel supplier gives you anything, it will be a gift card worth $100 as a matter of good will and nothing more.

You had a stock car with 250,000+ miles on a motor admittedly exceeding rated hp levels which let go when you were romping on it.

In any event, I want you to let us know what happens here because pf my super human curiosity skills.

[Marauderjack]

The lawyer in me says that if the fuel supplier gives you anything, it will be a gift card worth $100 as a matter of good will and nothing more.

You had a stock car with 250,000+ miles on a motor admittedly exceeding rated hp levels which let go when you were romping on it.

In any event, I want you to let us know what happens here because pf my super human curiosity skills.

Hey Marty,

I don't expect them to do anything but since another guy buys ALL the gas for his "Track Car" from the same "off brand" seller had the same problem I decided to point it out to them and they have replied. No way to prove but the "off brand?" transporter could have gotten a mixed load at his terminal...ironic we both had problems with fuel bought at 2 different Parker's stations at around the first week of November?? Also, this was the first time in 9+ years I haven't bought Shell 93 Octane....never a problem that I know of with the Shell gas......was it stupid of me to save $0.35/gallon....probably in hind sight!!:mad2:

The fact that none of the "High Mileage" engine components show any significant wear and tunes don't just change on their own says it was probably a fuel problem (no I did not put Kerosene in it)!!:shake:

Quite possibly my 174K mile fuel pump gave up.......new one going in now just to be sure!!:beer:

Steve is gonna start it after rebuild with the current tune to see what's what and go from there!!:beer:

Whatcha think the jury will say??;)

[martyo]

Whatcha think the jury will say??;)

I think if the jury gives you a $100 gift card it is because they are feeling the holiday spirit.

[Marauderjack]

Better than nuttin, huh??;)

[J-MAN]

Sounds like you have no hard evidence, why would this even go to trial much less a jury?

[Marauderjack]

Sounds like you have no hard evidence, why would this even go to trial much less a jury?

Helloooooo.....Boing....Boing! !:eek::shake:

Marty and I are pullin' each other's leg......you certainly cannot be serious...I HOPE!!??:shake::rolleyes:

[J-MAN]

You kidders you. :D

[sailsmen]

The typical Street S/C engine sees peak cylinder pressure ~20% + of Non-S/C.

It is the increased duration of peak cylinder pressure that produces the majority of the power increase.

At 6,000RPM "bad gas" can very quickly result in damage to multiple engine parts.