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Break-in is a very controversial subject for many. Especially for the uninformed or misinformed. Never take one perspective on this subject. Get as much information as possible and make your own choices. You only get one chance at this.
There are two camps regarding engine break-in.
One school of thought is that the manufacturer knows best, and their engineers’ recommended break-in procedures in the manual will result in the best results.
The other side basically says “ride it like you stole it”, or run the engine and drivetrain in aggressively.
Have you ever noticed that many magazine tests show bikes that make 2-3% more power than many consumers’ bikes or cars? Have you ever noticed that a dealer’s demo bikes run very well? Do you know why? Do you want to? It sure isn’t because these bikes are “ringers” that are built special – despite the old wives’ tales.
Personally, I am a big convert to the aggressive break-in using load and heat-cycles, and frequent oil changes camp. This is the result of break-in on many new engines – some of which I have built myself, and tested the methods.
Over the years, many things have changed. Clearances have decreased, machined tolerances have improved, operating temps have increased, materials have improved, fuels have more and more junk in them (and lubricate less), and oils have improved greatly. BUT the factories still recommend the same break in procedures. And oil change intervals. WHY?
If the engine is machined and assembled correctly, the only parts you need to wear-in or run-in are the rings and bores. Bearings (aluminum, Babbitt, roller, ball, etc.) do not wear in. If you have ever seen inside a freshly machined and assembled engine, you will see that the bores are purposely left rough. This is to help cut the face of the rings to match the bore wall shape, and make the ring seal best.
If the rings are not seated properly early in their life, they will not ever do so. Once the bore roughness is worn off (in the first couple of hundred miles), there is nothing left to cut the ring faces. The bores will actually glaze and prevent the rings from sealing. This is especially so on hard Nikasil bores using harder ring coatings than used on steel bores. Leak down % (blow by passed the rings) is the only way to measure the ring seal. This is why many engine builders also measure crankcase pressure closely during break in.
I have seen several engine builders tear down new engines that did not seal up correctly and then hone and replace rings in order to get their required leak down target percentage. As ring seal is improved, each 1/2 percent becomes a greater and greater issue.
The rough surfaces of the bores and rings break off and are either blown out with the exhaust (by coasting down), or collect in the oil. If the oil is not changed frequently during break-in, these metallic particles can collect and embed in the softer surfaces in the engine causing premature wear of these surfaces.
A cold engine and the same one when hot, will measure differently – especially the bores. As the engine heats up, the bores grow and distort. The pistons do the same. If you heat cycle the engine frequently during break-in, the pistons, rings, and bores will correctly wear to match each other.
There is no reason to rev the engine to the rev-limiter. The peak filling of the engine occurs at peak torque rpm. Turning the engine a bit over this rpm and letting it coast down will force the rings against the walls best, and suck much of the metallic particles from the bores and rings out of the engine.
Using mineral oil with frequent changes while loading the rings during break in produces a better seal than factory recommendations by NOT protecting the bores as well as synthetic oils will do. This improved ring seal makes more power and lives longer as well. This has been proven repeatedly by many engine builders of all types from F1 racing to Caterpillar diesels. Once the engine has sealed up, using good synthetic oil will protect from wear best.
Poor ring seal allows oil into the combustion chamber, carbon to form in the chamber, on the sides of the pistons, and in and around the ring grooves, unburned fuel and air will be blown passed the rings into the crankcase - diluting the oil and increasing crank case pressures. None of this is good for power or engine life.
The vast majority of wear in an engine is at the top of the cylinder bores. This is where the piston ring changes direction, and there is no oil to lubricate the bore walls, but the combustion heat is the most extreme. When the piston is at the top of the bore, the cylinder pressure during combustion is the highest. Any air and fuel leaking passed the rings here because of poor ring seal or ring flutter will burn oil under the rings and dilute the oil with fuel and carbon. This causes premature wear in all parts of the engine, and reduces power and efficiency in an ever increasing manner as oil is blown passed the rings more and more frequently and produces more and more carbon in the engine.
Most engines are at the end of their life when the ring seal is reduced to a given point. If you seat the rings better to begin with, and this seal prevents carbon from wearing the engine during its life, the engine lives considerably longer.
All of this can be seen and proven by testing compression, leak down, blow-by, and oil analysis.
The drivetrain responds the same way. Even ground gear faces need to see load to bed/wear in correctly. Frequent oil changes are even more important here. And a magnet on the oil filter helps tremendously.
If you cannot measure leak down, run the engine hard on mineral oil and change it frequently for the first 1000 miles (the first 200 miles are critical). Then add good synthetic oil and enjoy it for a long time.
I have seen engines that are broken in correctly make 2-3% more power compared to engines that are broken in lightly and never seal up – even more compared to engines that have glazed bores. These same engines also last longer, and use less fuel and oil.
Don't take my word for it; go ask any WINNING race team how they break in engines and drivetrain - in any motorsport. And ask them why they do it this way. Read the Mototuneusa web site. And listen to the “easy break-in” followers – but ask them to check their leak-down at various mileages. If none of this makes any sense to you, follow the manufacturer’s recommendations. Weeding out myth from fact is your responsibility - it is your bike.
If anyone that broke their bike in easy would like to visit me and have their leak-down checked, I am more than willing to do so.
Links:
www.mototuneusa.com
http://www.eng.wayne.edu/page.php?id=759
http://www.peterverdonedesigns.com/breakin.htm
http://www.peterverdonedesigns.com/600RRbreakin.htm
There are two camps regarding engine break-in.
One school of thought is that the manufacturer knows best, and their engineers’ recommended break-in procedures in the manual will result in the best results.
The other side basically says “ride it like you stole it”, or run the engine and drivetrain in aggressively.
Have you ever noticed that many magazine tests show bikes that make 2-3% more power than many consumers’ bikes or cars? Have you ever noticed that a dealer’s demo bikes run very well? Do you know why? Do you want to? It sure isn’t because these bikes are “ringers” that are built special – despite the old wives’ tales.
Personally, I am a big convert to the aggressive break-in using load and heat-cycles, and frequent oil changes camp. This is the result of break-in on many new engines – some of which I have built myself, and tested the methods.
Over the years, many things have changed. Clearances have decreased, machined tolerances have improved, operating temps have increased, materials have improved, fuels have more and more junk in them (and lubricate less), and oils have improved greatly. BUT the factories still recommend the same break in procedures. And oil change intervals. WHY?
If the engine is machined and assembled correctly, the only parts you need to wear-in or run-in are the rings and bores. Bearings (aluminum, Babbitt, roller, ball, etc.) do not wear in. If you have ever seen inside a freshly machined and assembled engine, you will see that the bores are purposely left rough. This is to help cut the face of the rings to match the bore wall shape, and make the ring seal best.
If the rings are not seated properly early in their life, they will not ever do so. Once the bore roughness is worn off (in the first couple of hundred miles), there is nothing left to cut the ring faces. The bores will actually glaze and prevent the rings from sealing. This is especially so on hard Nikasil bores using harder ring coatings than used on steel bores. Leak down % (blow by passed the rings) is the only way to measure the ring seal. This is why many engine builders also measure crankcase pressure closely during break in.
I have seen several engine builders tear down new engines that did not seal up correctly and then hone and replace rings in order to get their required leak down target percentage. As ring seal is improved, each 1/2 percent becomes a greater and greater issue.
The rough surfaces of the bores and rings break off and are either blown out with the exhaust (by coasting down), or collect in the oil. If the oil is not changed frequently during break-in, these metallic particles can collect and embed in the softer surfaces in the engine causing premature wear of these surfaces.
A cold engine and the same one when hot, will measure differently – especially the bores. As the engine heats up, the bores grow and distort. The pistons do the same. If you heat cycle the engine frequently during break-in, the pistons, rings, and bores will correctly wear to match each other.
There is no reason to rev the engine to the rev-limiter. The peak filling of the engine occurs at peak torque rpm. Turning the engine a bit over this rpm and letting it coast down will force the rings against the walls best, and suck much of the metallic particles from the bores and rings out of the engine.
Using mineral oil with frequent changes while loading the rings during break in produces a better seal than factory recommendations by NOT protecting the bores as well as synthetic oils will do. This improved ring seal makes more power and lives longer as well. This has been proven repeatedly by many engine builders of all types from F1 racing to Caterpillar diesels. Once the engine has sealed up, using good synthetic oil will protect from wear best.
Poor ring seal allows oil into the combustion chamber, carbon to form in the chamber, on the sides of the pistons, and in and around the ring grooves, unburned fuel and air will be blown passed the rings into the crankcase - diluting the oil and increasing crank case pressures. None of this is good for power or engine life.
The vast majority of wear in an engine is at the top of the cylinder bores. This is where the piston ring changes direction, and there is no oil to lubricate the bore walls, but the combustion heat is the most extreme. When the piston is at the top of the bore, the cylinder pressure during combustion is the highest. Any air and fuel leaking passed the rings here because of poor ring seal or ring flutter will burn oil under the rings and dilute the oil with fuel and carbon. This causes premature wear in all parts of the engine, and reduces power and efficiency in an ever increasing manner as oil is blown passed the rings more and more frequently and produces more and more carbon in the engine.
Most engines are at the end of their life when the ring seal is reduced to a given point. If you seat the rings better to begin with, and this seal prevents carbon from wearing the engine during its life, the engine lives considerably longer.
All of this can be seen and proven by testing compression, leak down, blow-by, and oil analysis.
The drivetrain responds the same way. Even ground gear faces need to see load to bed/wear in correctly. Frequent oil changes are even more important here. And a magnet on the oil filter helps tremendously.
If you cannot measure leak down, run the engine hard on mineral oil and change it frequently for the first 1000 miles (the first 200 miles are critical). Then add good synthetic oil and enjoy it for a long time.
I have seen engines that are broken in correctly make 2-3% more power compared to engines that are broken in lightly and never seal up – even more compared to engines that have glazed bores. These same engines also last longer, and use less fuel and oil.
Don't take my word for it; go ask any WINNING race team how they break in engines and drivetrain - in any motorsport. And ask them why they do it this way. Read the Mototuneusa web site. And listen to the “easy break-in” followers – but ask them to check their leak-down at various mileages. If none of this makes any sense to you, follow the manufacturer’s recommendations. Weeding out myth from fact is your responsibility - it is your bike.
If anyone that broke their bike in easy would like to visit me and have their leak-down checked, I am more than willing to do so.
Links:
www.mototuneusa.com
http://www.eng.wayne.edu/page.php?id=759
http://www.peterverdonedesigns.com/breakin.htm
http://www.peterverdonedesigns.com/600RRbreakin.htm
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