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Author Topic: piston failure chart  (Read 10621 times)

Offline rsss396

piston failure chart
« on: July 09, 2013, 10:12:25 PM »
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Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

piston failure chart
« Reply #1 on: July 09, 2013, 10:56:58 PM »
well not really I can't get the picture large enough to read the small print :(

it is a PDF file that I converted but it killed the quality how do I attach PDF's
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

piston failure chart
« Reply #2 on: July 09, 2013, 11:18:55 PM »
yes Dan the large image is photobucket and the small is attached, I can go as high as 400% on IE and its readable but not as nice as the PDF
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline atvmxr

piston failure chart
« Reply #3 on: July 10, 2013, 12:34:30 PM »
awesome!  

that next to last one should read big end rod bearing let go (it does vaguely hint at a lower end problem) ....  I've had that bite me a couple times not realizing that was the issue only to destroy a new piston in a few minutes....
Bunch of race quads that run on premix

Offline trx250r88

piston failure chart
« Reply #4 on: July 10, 2013, 10:44:35 PM »
Quote from: atvmxr;2505
awesome!  

that next to last one should read big end rod bearing let go (it does vaguely hint at a lower end problem) ....  I've had that bite me a couple times not realizing that was the issue only to destroy a new piston in a few minutes....

i had that happen last year too.the piston looked just like pic.rod bearing went,piston detnating on the edge.the motor still ran with major knocking noice.

Offline rsss396

piston failure chart
« Reply #5 on: August 05, 2013, 09:37:41 PM »
Piston seizures - by the technicians of Group K
It's a common sight. You see a boat on the beach with the       hood upside down and the top end off. A group of technical "guess men"       are assembled in a circle passing around a seized piston as if touching       it can give them greater insight as to the reason for it's failure. Unfortunately,       when this whole mess of parts gets dragged down to the shop on Monday morning,       the local mechanic may not be able to provide much more insight unless he       is very familiar with that particular engine's "sources of seizure".       It's a lot to ask.
Even among mechanics, there's plenty of confusion about what       causes a particular piston to seize. This confusion is compounded when the       mechanic only gets to see the remnants of the meltdown instead of the entire       machine. The following information will help to dispel some myths, and shed       some light on the understanding of piston seizures. The objective of this       article is to make piston seizures a part of your past.

Some fundamentals - Many people believe that piston seizures       occur when engine heat causes the piston to expand larger than the size       of the cylinder bore...this is not true. If you could freeze your engine       "in motion" in the middle of a long full throttle pass, and disassemble       it for micrometer measurement, you would find the piston to measure at a       .0005" to .0015" press fit into the bore. That's right, a slight       press fit! The reason that it doesn't seize is because the premix oil has       such a terrific film strength that it acts as an irremovable buffer between       the piston and the cylinder. That is, the bare metal surface of the piston       never actually touches the bare metal surface of the cylinder because the       oil stays between them. Many mechanics have experienced this phenomenon       while cleaning a freshly bored cylinder. Completely dry without cleaning       solvent, the piston moves through the bore with difficulty. After rinsing       the piston glides all the way through with no resistance at all. This is       because the solvent acts as a film between the piston and cylinder.
A piston seizure can only occur when something burns or scrapes       away the oil film that exists between the piston and the cylinder wall.       Understanding this, it's not hard to see why oils with exceptionally high       film strengths are very desirable. Good quality oils can provide a film       that stands up to the most intense heat and the pressure loads of a modern       high output engine.
The difference between seizure and scoring Seizure and scoring       are two different stages of the same problem. When the oil film on a cylinder       is momentarily burned or brushed away, the metal surfaces of the piston       and the cylinder wall will actually touch. When this happens, there is a       sort of scraping that takes place between them. When the oil film is resumed,       the marks from this scraping will often remain on the piston and (or) the       cylinder wall. This momentary scraping or "scoring" seldom causes       any permanent or performance robbing damage. No significant damage takes       place because the oil film is resumed before the piston and cylinder have       a chance to start exchanging material onto one another.
Scoring is commonly seen on the piston face directly below       the piston ring end gaps. The blast of combustion can get between the large       end gap of a worn out ring and burn the oil off the piston and cylinder       in that area...Hence the surface scoring. In most cases, score marks can       simply be sanded off of the piston and cylinder. However when ever you see       scoring, it's a good idea to find the source so that it doesn't develop       into a full blown seizure.
Seizure is a case of scoring where the oil film does not immediately       return. After a few moments of constant scoring, the piston and cylinder       will scratch each other hard enough to remove material from each other.       This floating material grinds itself into the piston and the cylinder as       it continues to grow in size. As this snowballing material grows, it will       drive the opposite side of the piston against the cylinder wall with a pressure       so terrific that scoring begins to take place. While all this is going on,       your engine is still running wonderfully at full throttle.
The death blow comes when the mass of material between the       piston and the cylinder wall finds it's way to the piston ring. This nearly       molten mixture of aluminum and iron will instantly lock the ring in it's       groove. This ring locking, not the piston surface seizure, is what actually       causes your engine to quit. When the piston ring becomes locked back in       it's groove, it's incapable of providing compression sealing against the       cylinder wall. This instant loss of compression, while the engine is at       speed, causes a dramatic loss of power. That power loss, along with the       added drag of the badly seized piston, makes the engine quit or lock up       in a nanosecond. In fact this entire seizure process, from the first scoring       scratch to the piston locked solid, takes less than a second at full rpm.       That's not even enough time for you to utter the first syllable of your       favorite profanity.
There are many different causes or sources for piston seizure.       Each cause has it's own symptoms and it's own visual results. The following       is a description of several very common types of seizures, and the most       common problem source for each one. It should be understood that diagnosing       piston seizures is not done with any precision by even the best engine builders.       However this information may allow many of you to make a more educated and       accurate guess.
Four corner seizure - This is by far the most common type       of seizure found in personal watercraft engines. Both sides of the piston       will show heavy scoring and seizure marks on each side of the wrist pin       hole. The pattern of these four seizure points often appears to be a perfect       square, hence the slang term "four corner". The scoring takes       place in this pattern because those areas of the piston casting are the       thickest. When the piston is seriously overheated, the thick areas will       expand and distort the most. High output motorcycle engines usually experience       this type of seizure pattern when a piston has been fitted with too little       clearance. Most experienced , and well meaning, motorcycle mechanics would       take one look and immediately say that insufficient piston clearance is       the cause. However that diagnosis, on watercraft engines, would be wrong       about 99% of the time.
Four corner seizures in watercraft engines are almost always       a result of the engine creating more heat than the cooling system can exchange       away. That is not to say that most cooling systems are under built, but       rather that it's easy to make a modification that creates too much internal       heat for even the most beefed up cooling systems. Even though a constant       feed of cool water is being moved through the cooling system, the cooling       system must be capable of exchanging the engine heat away at a rate quicker       than the engine is creating it.
 
 
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

piston failure chart
« Reply #6 on: August 05, 2013, 09:44:39 PM »
The engine factors that have the greatest seizure related       effect on operating temperature or excessive compression ratio or ignition       advance, high rpm, insufficient fuel octane level, insufficient cooling,       or any combination of these. Properly adjusting these same factors will       have the greatest effect on total power output. The job of the professional       engine builder is to find the right combination, or "blend", of       these factors that will result in strong overall power output at a pace       that your cooling system can keep up with. There are many mechanics and       engine builders who have mastered their own combination "blend"       that can get you all the power your after without risking a seizure.
A group of mismatched modifications is a first class ticket       to "seizure-land". Any inexperienced individual who sets up your       engine with over 200 psi of compression and advanced timing, is also guaranteeing       your arrival. If your big mouthed motorcycle buddy down the street tells       you that he can make any engine "roost"...you should think twice.       You could be in for a very expensive lesson.
Lean seizures - Despite what most people think, lean fuel       mixture seizures on personal watercraft engines is actually a very rare       occurrence. The high speed circuit on almost all personal watercraft carbs       is responsible for delivering fuel in the 30%-100% throttle range. If the       high speed circuit is lean enough to cause piston seizure, it will also       cause an almost un-ridable hesitation or laziness in mid-range throttle       response. Dangerously lean high rpm racing motors can sometimes offer acceptable       mid-range, however they will accelerate to peak speed very slowly.
The classic lean seizure exhibits heavy scoring and seizure       along the entire width of the exhaust port with only light scoring on the       opposite piston faces. In lean mixture conditions, the exhaust gas temperatures       escalate quickly into the meltdown stage. Those high temperature gases can       compromise or completely burn off the oil film on the exhaust piston face       as the exhaust port is being covered up. With the oil film weakened or gone,       scoring quickly turns into seizure and ring locking.
Air leak seizures - These are very common seizures because       air leaks themselves are so common in watercraft motors. If you could pressure       check every engine that showed up at a local racing event, you would find       over 50% of them to have an air leak. Because of the varying degree of these       leaks, some will result in seizure, others will only cause poor carburetion       or slight overheating. The varying effects of these air leaks makes this       a difficult diagnosis.
In any situation where an engine has seized for no apparent       reason, the motor should be pressure tested before any other teardown work       is performed. If a mechanic does not have the equipment to pressure test       your seized engine, it's very unlikely that he will have the finesse to       accurately diagnose your problem either. In fact, pressure testing should       be a standard finishing procedure for any major engine reassembly work.       Race engines should be pressure tested no less than every 20 operating hours.    
The air leak piston seizure, depending on the severity of       the leak, can look like a four corner type or a lean mixture type of scoring       pattern. If an engine is operating on the ragged edge of overheating, a       small air leak can easily cause the extra overheating that will result in       a four corner seizure. On the other hand, a huge air leak will draw in so       much additional air that even an over rich engine can experience a lean       type seizure at full rpm's.
Detonation seizures - If a modified engine has been prepared       with too much compression or spark advance, or if it's run on unacceptably       low octane fuel, it will begin to "ping" or detonate. Detonation       is a big subject the merits another article of it's own. For now we only       need to understand that it causes a terrific amount of internal heat in       a very short time, as well as physical damage to the combustion chamber.       If you have ever seen the outer diameter of a cylinder head dome that looks       as if it's been eaten by termites, you have seen the results of detonation.       It packs a physical force that is roughly equivalent to hitting the edge       of the piston crown with a full arm swing of a ball peen hammer. In a short       amount of time, this detonation pounding will collapse the ring land and       lock the ring in place (usually on the hotter running exhaust side of the       piston). As soon as the ring is locked, the flames of combustion burn the       oil film off of the cylinder wall, and the scoring/ seizure process begins.       Because of the exhaust side scoring and the swift overheating caused by       detonation, you'll have a 50/50 chance of a four corner seizure or a "lean       mixture" appearing seizure. Only an experienced watercraft engine builder       will be able to accurately diagnose this seizure source.
Cooling system seizures - This cause cuts into the gray area       of piston seizure. A clogged cooling system on any machine can cause swift       and serious temperature problems. However, no engine will ever experience       a seizure purely as a result of inadequate cooling from the stock system.       I have seen several 50+ mph modified boats run an entire trouble free season       with a bone stock cooling system. These engines are not a statement of the       effectiveness of the stock cooling system, but rather a statement to the       benefits of having a professionally prepared high performance combination.       The larger line and dual line cooling kits certainly have their merits on       high output race engines that will be run at full throttle for extended       periods of time. Their ability to more rapidly exchange away engine heat       is a great asset on modified engines that are run at full throttle only.       However, none of them can exchange away the excess heat created by a poorly       prepared engine package. If you are experiencing chronic piston seizures       of any kind, increased cooling may temporarily stave off the problem, however       it will almost never cure it.
Piston clearances - As mentioned earlier, too little piston       clearance is one of the most common "wrong" diagnoses made on       seized watercraft engines. Most of today's watercrafts come brand new with       cylinder clearances that are .001"-.002" over the recommended       factory setup clearance. This extra clearance is an added protection against       riders who don't follow the proper break-in procedure. If the clearance       of a bored cylinder has been set at the factory recommended clearance, the       close piston clearance by itself will not cause seizure. There is usually       an added factor such as excessive compression or an air leak. If a piston       if fitted with too little clearance, it will usually experience a four corner       type seizure pattern. In most cases the ring will experience little or no       damage. If this is the case, it's entirely safe to sand the score marks       off the pistons and re-use them in the freshly honed cylinder.
Too much piston clearance can also result in piston scoring       and seizure. A piston ring, in an excessively large cylinder bore, will       have a very wide end gap not to mention very weak ring tension against the       cylinder wall. The flame of combustion can easily burn past this weak ring       seal as well as down the end gap opening itself. If this flame burns off       a significant amount of the oil film on the cylinder wall, the scoring seizure       process begins. Piston seizure caused by excessive clearance is much more       common than you might think, particularly on iron cylinder 550's.
Break in seizures - The most common break in related seizure       is usually caused by the ring not the piston. Most new piston rings come       with a gray or green Teflon coating on their outer sealing surfaces. This       coating seals to the cylinder wall in just a few operating minutes, which       provides better power during the break in period. As the engine is breaking       in, the Teflon eventually wears away and lets the hard surface of the ring       come in from behind to provide the long term seal. The down side of this       Teflon coating is that it makes for a dangerously small end gap during the       first hours of operation. If the engine is run too hard too soon, the heat       will cause the ring to expand in diameter which will drive the ring ends       together and drive the ring surface hard against the cylinder wall. A piston       ring that is being overheated in this fashion will easily have enough tension       against the cylinder wall to scratch off the oil film which will begin the       scoring/seizure process. A piston seized in this way will have heavy scoring       around the entire diameter of the piston, with the ring usually locked into       the groove all the way around as well.
 
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

piston failure chart
« Reply #7 on: August 05, 2013, 09:45:54 PM »
Lubrication related seizures - By now it's apparent how important       the oil film strength can be. Equally important is the amount of oil that       is present in the engine. Most watercraft engines carry factory recommendations       for oil premix ratios between 40:1 and 50:1. For the rpm's and operating       temperatures of a stock engine, these mix ratios work fine. However if your       rpm range is significantly raised by aftermarket modifications or bolt on's,       you may need to increase your mix ratio slightly. The total amount of time that it takes for a drop of oil to       get from the carburetor, to the lower end bearings, to the top end, and       out the exhaust port is called "oil migration time". As peak rpms       increase, the amount of time that a drop of oil remains inside the engine       is drastically shorter. In other words, a 9000 rpm race engine would need       a mix ratio of about 32:1 to maintain the same internal lubrication presence       that a stocker would have with a 50:1 mix. There are several oil brands       that claim that their oil can provide equal lubrication at a leaner mix       ratio (60:1 or 80:1) because of a claimed better lubrication quality. In       my 20 years of working on racing motors, I have never experienced this to       be true nor has any oil manufacturer, to my knowledge, proven it to be true.       It's like running your truck on two quarts of a special oil instead of four       quarts of a standard type oil. The quality cannot make up for the quantity...ever.    
Fables and untruths: Cold seizure - this is by far the most       over used "seizure scapegoat". It some how implies that the rider       ran his engine in a way that caused the failure. At least 95% if the "so       called" cold seized engines that I've seen have had a very apparent       problem elsewhere in the engine that the original technician failed to see.       Telling a customer that he cold seized the engine is an easy way for a mechanic       to immediately reverse the guilt and the responsibility. If a freshly bored engine or a high performance engine were       started from stone cold, and then run hard at high rpm within 30 seconds       of the start up, it could very likely experience a true cold seizure. This       happens because the aluminum piston would experience a radically faster       rate of expansion in that 30 seconds than the cylinder does. The reason       for this difference in expansion rate is two fold. First and foremost, the internal temperatures that the piston       crown is exposed to at full load are on the order of 800°F - 1100°F.       The gases passing through the exhaust manifold ports is also in this 800°       -1100°F temperature range. The expansion rate caused by these temperatures       is usually not a problem when the water entering the exhaust manifold is       being preheated by the very hot exhaust port passages. However in the first       30 - 50 seconds of operation, these internal exhaust ports have not yet       absorbed the heat that's needed to properly pre heat the cold incoming water.       During the first 30 operating seconds, this cold incoming water will briefly       maintain the water jacket around the cylinder at "stone cold diameter"       while the piston is becoming "full temperature diameter". On engines       with properly sized pistons, the difference in these diameters becomes much       more than even the best oils can withstand. Any engine that has been warmed       up for 60 seconds or longer, would be virtually incapable of a "cold       seizure"
Cold water seizure - Like many other people, I have operated       stock as well as heavily modified machines in water as cold as 51°F       with no seizure or scoring problems of any kind. These are all typical machines       that were all originally prepared to operate in 60° - 80° water.       It is my opinion that as long as proper warm up is performed, blaming water       temperatures down to 51°F for any piston seizure is just another case       of scapegoating. I can honestly say that I have absolutely no expectations       of ever testing any high output engines in water under 50°F. I would       be keenly interested to read an article from any thawed out individual who       has.
Hot water seizure - the hottest water I have ever operated       high output race machines in is 92°F. These particular machines were       equipped with the same single cooling line system that they had used in       the 62°F ocean only two days earlier. Both test sessions put these machines       (a 550 modified and a 650 modified) through numerous closed course and full       throttle radar tests. Subsequent internal engine inspections showed no signs       of any piston scoring or seizure what so ever. There was no doubt that the       warmer water caused both machines to lose peak speed ability after repeated       radar passes. However these losses leveled out after 4 or 5 passes. When       the machine was permitted to cool down briefly, the higher peak speeds would       return. While this one experience may not necessarily qualify as the gospel       for every machine in the nation...It qualifies for me.
Leaning out - this is a term for a phenomenon that doesn't       exist. It implies that a carburetor, whose needle/seat and high speed metering       screw is properly set, will suddenly begin to meter slightly less fuel to       the engine for no apparent reason. This does not happen...ever. In most       cases what a rider is actually referring to is the way his machine begins       to slow down noticeably during a long full throttle pass. In most cases       this slowing is the result of a serious overheating problem caused by excessive       compression, ignition advance or poor quality gasoline.
Seizure by running out of gas -
as many people already know,       a larger size needle and seat must often be installed into a carburetor       to contend with the increased fuel demands of a moderately modified engine.       If a modified engine is operated at full throttle with a stock size needle       and seat, it will usually carry full rpm for about 2 or 3 seconds and then       shut off as if someone hit the kill button. When the machine comes to a       stop, the rider touches the start button to see what the problem is. The       engine, no longer in fuel deficit caused by the undersized needle and seat,       unexpectedly starts right up. This instant high speed shut off is caused by the carburetor       literally running out of gas. It is sometimes implied that during this shut       down moment of fuel starvation, the engine is also starved of the oil that       is pre mixed in. This perceived oil starvation is then blamed for any subsequent       piston scoring or seizure. Watercraft pistons do not seize in this way...ever.     At the moment that the fuel starved engine shuts down, combustion       and all the heat associated with it "ceases". Unlike a motorcycle       whose rear wheel traction continues to move the pistons in the bores at       a very high "friction causing" speed, the propeller and pistons       in a fuel starved watercraft stop turning almost instantly. The heat and       movement friction that can cause seizure are virtually non existent in a       fuel starved watercraft shut down. This same concept applies to any machine       that simply runs it's main tank dry before having to switch to reserve.     It is possible for a rider, whose carb has an under sized       needle and seat, to induce a piston seizure. However this would require       a great deal of combined skill and stupidity. Once the rider has established       that extended full throttle operation causes his engine to quit, he might       make the very poor choice of only applying enough high speed throttle to       avoid starving the engine. When he does this, he will be capable of maintaining       about 90% throttle which will hold the engine endlessly on the lean thresh       hold of fuel starvation. As this rider eventually masters this throttle       position, he will be able to maintain a very high rpm with the carb feeding       a horrifically lean mixture. Ultimately his finesse will be rewarded by       one of the most abrupt and destructive lean mixture seizures that his mechanic       has ever seen
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

 

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