Comments by "g simpson" (@GSimpsonOAM) on "Repairman22" channel.

The only advantage listed is piston friction which is minimal. The last engine I reconditioned had 220,000 km on it. The bore & piston wear was minimal but the rings were worn to half their original thickness. A new set of rings was all that was required. It may have some benefits but I am skeptical of claims of any improvement in efficiency.
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@erroneousbosh Rings have long been designed to bed in to match the bore. To add to my original post the engine was a supercharged Lancia Beta engine and had 320,000 km on it 10 years after the new rings. Was still reliable and going strong.
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Wrong at 5:30. It still relies on a valve spring so just as prone to valve bounce. The FIAT 600 competitor shown can rev well past 5000 no problem. This system is poor at generating torque to turn the camshaft. The offset from the center of the rotation is small compared to a steam loco arrangement.
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@andrewpipitone1572 Finally. A sensible comment/question. The friction of the piston is small amount of energy loss. If it was significant then the piston the the wear in a conventional piston would be very high. This is not the case. For the claims of the efficiency to be so good then the thermodynamic efficiency would have to be much better. As it uses the same cycle as a conventional engine then the starting point for the efficiency is the same. Whether Otto or Diesel cycle. So yes it will work. Yes the piston design reduces piston friction but this won't improve efficiency as the promoter claims.
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@Steevo69 It is a variation on the Otto cycle burning fuel so not claiming to be perpetual motion machine. The piston weight was claimed to be lighter not zero
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@bb21again.67 Of course but it can physically touch the wall of the cylinder. The concept of this engine is that the piston cannot touch the cylinder walls.
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@s.lacasse8337 Have you seen the size of conrods on other engines. In this engine the conrod still takes the main load to crankshaft.
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@SimonJ57 Yes indeed. The only thing it addresses is piston friction which is small. It does not do anything different than a regular engine thermodynamically so claims of major improvements should be taken with a grain of salt.
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@bb21again.67 1/ I understand how lubrication in engines work 2/ I have repaired many high mileage engines and the wear on the pistons is usually the least ones problems
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@bb21again.67 It reduces friction by physically guiding and preventing the piston from touching the cylinder bore rather than a film of oil in a conventional engine.
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@DoyleHargraves Conventional engines use an oil spray to the bore combined with oil control rings to minimise friction. With some success given the lifespan of the average piston.
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@limesta I don't. The transfer Is from piston to gudgeon pin to conrod to crankshaft. Just like a conventional engine. 1:16 The rocker arm is just a guide and does not transfer power.
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@harrickvharrick3957 The gudeon pin, pivot bearing, big end bearing and main bearings are going to ensure there is still plenty of oil flying about so no change.
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@dougmiller7643 If there was significant friction in conventional pistons then they would not last 5 minutes. In reality they last 100s thousands of km/miles.
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@KidAgainHobbies Some engines will do that mileage. A large, lightly loaded engine will last longer. Bear in mind the engine I described was a high performance 4 cylinder supercharged engine. I had the engine out for a transmission issue and inspected the engine due to it's mileage. Waiting until rings break is unwise as it can damage piston and bore. As it was I had 10 years trouble free motoring after doing the job.
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@KidAgainHobbies It is not as simple as that. A car that only does short journeys where the engine is cycling temperature wise will not last as long as an engine doing highway cruising where it is up to temperature most of the time and under steady load. Maintenance and using the correct lubricants affects longevity but also the conditions under which it is operating. For example a small engine will do better for short running than a larger engined car as it heats up much quicker. This reduces wear and better gas mileage.
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@TheLUKONZEN No. One can calculate the theoretical thermodynamic efficiency of a combustion cycle. This is about 29% for petrol/gas and 39% for Diesel. (in an engine with no losses) Piston friction only represents a small amount of losses in engine. If it was significant the piston would not last long.
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@bb21again.67 Something for you to look up "Thin film lubrication mechanism"
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@bb21again.67 I have 40 years experience as an engineer. Have a couple of Diplomas in engineering. Balanced many items including crankshafts, helicopter gyros and many other things. I have worked on many types of motors and industrial equipment. Currently I am the Chief engineer of a large industrial engine room. The projects we do require a fundamental understanding of the mechanics and theoretical nature of the thermodynamics involved which are far too complex to elaborate on a forum such as this. So I can call BS on an idea that doesn't pass the sniff test
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@bb21again.67 I have done a few high mileage engines. When the pistons are replaced is is because the engine is rebored to a larger size due to the rings wearing the bore rather than the pistons being worn. Going back to my original post. The piston friction and even ring friction is minor. The only way the efficiency of the engine significantly is to increase its thermodynamic efficiency. This can be done just as easily with a conventional engine. The basic parameters to consider are the bore, stroke (and their ratio) and the compression ratio which is limited by the octane rating of the fuel. I have balanced crankshafts but most of my balancing experience has been with helicopter gyros.
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@TheLUKONZEN The heat generated from piston friction is a tiny fraction of the heat generated from thermodynamic losses. For example a 100kW motor generates 300kW of losses at 25% efficiency. Apply 300kW of energy to a piston and it won't just cause it wear you will have a molten pool.
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@dancetweety10 As already discussed the friction losses from piston to bore contact is trivial
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@dancetweety10 If you are going to reply yo a thread with over 130 replies and not bother reading them don't waste my time. I am not going to repeat myself.
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@dancetweety10 you saw it on YouTube so it must be true
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@dancetweety10 I find it amusing that you trust a glossy animation over dry mathematics and thermodynamic theory. I suggest some study for you. The Otto cycle https://en.wikipedia.org/wiki/Otto_cycle Thermodynamics https://en.wikipedia.org/wiki/Thermodynamics If you get your head around that then you may get an understanding how you were hoodwinked by a flashy presentation.
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