Offset bores?
03-19-2008, 03:05 AM
#21
Those engines actually had multi piece crankshafts with splined pieces that would press together. If you notice the rods are single piece and have ball/needle bearings where they ride on the crank. I don't think cylinder phasing is right on that pic with all the valves and stuff, I can't imagine anyone ever getting to ballance correctly like that. Would have atleast thought the other side of the crank would be 180 degrees off.
I can't imagine ballancing that was any worse than Honda's V-5 (yes, a V-5) MotoGP bike that used varrying bores and to ballance the rotating assembly. Its funny how quickly this thread has turned into a "look at all this crazy **** Hondas doing
I can't imagine ballancing that was any worse than Honda's V-5 (yes, a V-5) MotoGP bike that used varrying bores and to ballance the rotating assembly. Its funny how quickly this thread has turned into a "look at all this crazy **** Hondas doing
press together bottom end!?!?! sounds cool. guess you could then use proper bearings on the big ends. wonder if it would be stronger than a conventional crankshaft??
do these bike engines run any type of balancer shafts or anything??
Chris,
03-19-2008, 11:04 AM
#22
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hmmmmm the Honda V5! what an amazing engine. think they should bring it out on a road bike! lol
press together bottom end!?!?! sounds cool. guess you could then use proper bearings on the big ends. wonder if it would be stronger than a conventional crankshaft??
do these bike engines run any type of balancer shafts or anything??
Chris,
press together bottom end!?!?! sounds cool. guess you could then use proper bearings on the big ends. wonder if it would be stronger than a conventional crankshaft??
do these bike engines run any type of balancer shafts or anything??
Chris,
Press together bottom end can be useful in the fact that you can use real "bearings" instead of the hydrodynamic 2 pieces ones in conventional motors. They fail though in the fact that each piece is splined where it meets the other pieces and that is your weak link. They're typically in 1-3 cylinder engines of older design, that Honda is the first 4/8? cylinder I've seen that is press together also. They do allow for really cool things to happen in the case of the Kawasaki H1/H2. They were 500/750cc 2 stroke 3 cylinders with cylinders and bottom end cases as one piece, but seperate from another cylinder. Crank was press together also, so you could put together as many cylinders as you wanted. 100% modular engines are neat, sucks you have to make them weak to do it.
04-21-2023, 02:24 PM
#23
no it’s better ,I know this is very old and I didn’t read every single entry,but the offset prevents everything you’ve mentioned that's the point.the offset keeps the rod and piston going up and down equally on all sides of the cylinder,producing more power due to less friction ..all none offset cylinders are loosing power due to increased friction it also weakens the rods under heavier loads as it is also always trying to spin the rod bearings and all the forces are directly aimed at the small end of the rod which also means the motor can handle less power than off set motors everything else being equal..plus a none offset engine wastes power through friction so the more power a engine makes the more friction and more power wasted as the piston is driven into the cylinder wall..
04-21-2023, 04:24 PM
#24
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I was reading some stuff the other day about the Honda Insight engine using offset bores to move the connecting rod inline with the piston during peak cylinder pressure. I know it would require a custom one off block and I'm not really interested in trying this out myself just curious to see if its ever been done on anything but this motor. Valvetrain would probably also be beyond wacky, when is GM supposed to come out with that OHC LS motor?
Stolen from InsightCentral.net
"The engine block has a unique, offset cylinder design in which the bore center is offset 14mm from the crank center. Maximum combustion pressure occurs at a point where the connecting rod is straight up and down in the cylinder. In this position there is zero lateral force so friction and piston slap are reduced.
As a result of the offset construction, the combustion pressure is used more efficiently since the rod is near it maximum leverage point with the crankshaft."
Stolen from InsightCentral.net
"The engine block has a unique, offset cylinder design in which the bore center is offset 14mm from the crank center. Maximum combustion pressure occurs at a point where the connecting rod is straight up and down in the cylinder. In this position there is zero lateral force so friction and piston slap are reduced.
As a result of the offset construction, the combustion pressure is used more efficiently since the rod is near it maximum leverage point with the crankshaft."
Every 4 cylinder Honda I've seen coming out now has an offset bore
Edit: if someone reminds me in a week I can dig through my laptop and find some stuff wrote up about cylinder offset
