The "famous hudson hornet" has a bit of a story about this... as Smokey Yunick was the mechanic on it.. he wanted to offset the bores like this but they wrote in the rule book "you can not offset bore the cylinders in the block from factory position" so Smokey Yunick offset the crank in the block...😂 and moved the gearbox across aswell... always thinking 1 step ahead of the officials
This "désaxé" principle was followed by top-class designers such as Henri Toutée. Hard to say who originated the idea, but it certainly dates back to the early 1900s. My 1934 Chenard et Walcker has slots cut into the lower cylinder areas to accomodate the bias of the connecting rods! The balance problem is probably why the forward face of the flywheel casting includes a hefty annular integral "balance" (?) ring. I was thinking about machining it off, but your timely explanation is making me re-think!
This "Offset Cylinder Design" was First used by the Rambler Car Company in 1908. Other Designs are an, Offset Connecting Rod, shaped as 'b' or 'd' - where the "circle part" connects to crankshaft-conrod journal - the "Top of vertical line" to piston. The connecting rods (con-rod) used in this Video are standard "I-rods" - centered equally to the con-rod journal and are almost exclusively used in engines. Experiments with "b & d" conrods go back some 50yrs and both were found to create "Piston-dwell" at TDC & BDC, depending on - degrees of offset. Patents for Offset Cylinder and b & d Con-rods have Expired, are now Public Domain.
The very first polytechnic course I did when I became a motorcycle mechanic ( about 40 years ago ) , involved stripping and measuring an old ( already old at that time ) Briggs and Stratton lawn mower engine . Those engines today would be perhaps 60 years old , and they had cylinder offset . I recall that because I had never considered the possibility and was questioning my measurements . I don’t recall the amount , it wasn’t enough to see with the eye , but it was there . I think 1 or 2 mm . Honestly , I’ve always thought it was a normal part of engine design since ( maybe they are pushing that offset further now ) .
It is indeed a normal part of engine design. A small connecting rod angle on TDC keeps the piston held towards one side of the cylinder, which prevents it from rattling in the bore as it changes direction. But that is, as you found out, only a couple of millimeters or so.
This is known as the desaxe design. It has been used frequently over the decades. The true endorsement of it's advantages would be it's use in racing engine design and offhand I don't know of one, although there must be, given the constant quest for advantage in racing.
Cylinder offsets are as old as the 4 stroke engine. And depending on the engines use, can be great, or a huge liability. When off throttle, with high compression ratios, it's not uncommon to break the piston or the rod, or both, with the severe rod angles on the up stroke in off throttle scenarios.
pelo que se pode entender essa inovação pode ser aplicada em qualquer motor, e não ficaria nada surpreso se encontrasse um antigo motor diesel com essa configuração, pois é até meio óbvio que a força não deve ser aplicada linearmente sobre o eixo e sim no deslocamento, assim como fazemos ao pedalar bicicletas. Bem problemas com patentes a parte, se pegarmos um bloco de motor convencional cortarmos justamente no final da camisa do pistão e adicionarmos uma junta em ângulo, do mesmo material que o restante do bloco, tudo que temos que fazer é ajustar o comprimento das bielas para ter um motor que atenda essas novas especificações... se o corte for bem feito e a junta tiver as medidas muito bem calculadas, nem ajuste de bielas será necessário... O bom disso, é que esse novo motor além do benefício do novo ângulo ganha também sobrevida pois as retificas podem explorar esse novo ponto de corte para eventuais correções e ajustes. Uma pena eu não ter uma oficina ou dinheiro para fazer os testes... mas talvez alguém ai lendo isso sinta-se inspirado a fazer esse teste...
We have used longer rods and shorter strokes in the past Over-square allows higher RPM and less piston slap. This is due to the angle of rod and piston is less.
I suspect this came about from curiosity of hot rodders use of piston pin offset for power gains. In other words flipping the pistons opposite of oe installation. The offset cylinder would have been a logical progression of that idea.
Effects on a two cycle engine such as non symmetrical port timing , increased transfer velocity, effect of a longer stroke mechanical leverage, and a longer power cycle.
The only reason you would do it is to reduce engine height. And you could reduce engine length if you stagger every second piston. Volkswagen VR5 and VR6 engines used it.
@@B1g_Tarn I do a lot of translating work for Yamaha in Japan but I've only done a few outboard jobs for them. I'm headed over there next week and will ask my contacts there. If they're also using them in the OBs perhaps they're using them in most of their engines.
when this offset would gain enough,all the engines would have been build like this,long ago. but buildingcost,to overcome the specific needs for this style engine are probably higher then the gains.
Toyota in the ‘90’s claimed to have cylinder offset in a concept car, it also had soft valve springs as the engine was designed to not rev past 4000rpm. I remember all this but not the concept car.
I have wondered about cylender cant and offset combined. Small amounts. Some of my questions are in the offset what happens with cam timing and duration ramp rates. Then, flame time and piston speed down the cylender. Fuel flame speed. It seems in an offset torque would increase. Cylender cant may also improve Torque. It may also improve piston side load. Just thoughts.
So thinking about this, If you had a 90* V12 or 190*boxer engine, with offset cyls, its possible to counterbalance it completely with almost no weights.
It confused me. I thought the counter weights on the crankshaft were primary (countering the weight of the piston and wrist pin going up and down or side to side in a boxer) and secondary forces were generated by the weight of the big end (essentially being thrown from side to side).
Interestingly enough I thought about it as well once in 1976 then again briefly in the summer of 1981. I had intended to build a totally custom one off V12 engine to test things out but I forgot about it until this very moment thanks to this video. Time to get to work.
Good point @Einimas I do remember hearing it had issues with vibrations even though they call it the "compact inline 6"which is very ironic Maybe they can make one side normal instead?
Find a better description of an offset engine. This is clearly written by somebody who doesn’t have English as their first language and they’re using artificial voice.
It seems as if the friction is most important however it is mostly about newton times distance, make a sheet showing the total area (integral) of the newton meter curves for each engine resulting in a power advantage.
It would be very strange for a boxer. Because of the opposed cylinder layout, in order for both banks to have the correct offset one bank would be raised higher, and the other would be lowered. I feel like that would create problems with assembly and strength, and may make it harder to properly lubricate and cool the motor.
Connecting rod failure is almost always attributed to failure of the rod bolt & the rod bolt is under the most stress at TDC at the end of the exhaust stroke & at the beginning of the intake stroke… that’s when rod bolts break & an offset cylinder makes it even worse. Yeah, you might make more power with a severely offset cylinder, but it comes at a cost of reliability.
