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450robot
11-12-2005, 12:59 PM
i was bored today, and this idea popped into my head when me and my buds were talking about the future of motors and whatnot...

has anybody ever had an engine where instead of the cam chain, there was like a crank rod?

i dunno if it would be better, or more reliable, but there would be no more chain tensioner or worn out chains to worry about

just thinking

11-12-2005, 01:12 PM
i would think it wouldnt be applying the same amount of force on it at all times as the chain would, just my thought

ZeroLogic
11-12-2005, 01:44 PM
i think its already been done for like old engines not sure but i think i saw that somewere if not copyright it!:devil:

harescrambles
11-12-2005, 07:29 PM
What about just three gears?

450robot
11-12-2005, 08:06 PM
accually, ducati, or some motorcycle company has done the gear drive thing, they had a series of about 8 gears running from the crank to the cam, the bike is in production too, so it must work well

PunkA$$
11-12-2005, 08:14 PM
Also your diagram on the left has a 1:1 ratio. You would require a 2:1 ratio (two crank turns to one cam turn). :macho:

450robot
11-12-2005, 08:18 PM
Originally posted by Punk*****
Also your diagram on the left has a 1:1 ratio. You would require a 2:1 ratio (two crank turns to one cam turn). :macho:

i know, i really didnt focus on ratios, measurements or accuracy... i was just giving a quick paintshop example

PunkA$$
11-12-2005, 08:53 PM
Originally posted by 450robot
i know, i really didnt focus on ratios, measurements or accuracy... i was just giving a quick paintshop example

How would you achieve a different ratio with that setup though? Not trying to be a smart*****, but seriously it doesn't seem possible.

honda350r
11-12-2005, 09:04 PM
The picture does not work at all.. The rod would just pivot at the botom or top and never make a full revolution !!

A belt is actually the best for making power :devil:

450robot
11-12-2005, 09:06 PM
if you had the right size wheels (gears, whatever) it would be possible, it might only spin the wheels at a 1:1 ratio, but given that the cam is alot smaller than the cam wheels it would reduce the ratio at the cam, get the sizes right and you could have a 2:1 ratio

it would work just like the chain, because even with a cam chain, the piston might cycle twice, the cam will only spin once

honda350r
11-12-2005, 09:10 PM
Originally posted by 450robot


it would work just like the chain, because even with a cam chain, the piston might cycle twice, the cam will only spin once


NOT !!!

450robot
11-12-2005, 09:21 PM
yes! the piston will hit tdc twice, while the cam will spin one full cycle, opening the intake valves on the first tdc cycle, and exhuast valves on the other tdc cycle, therefor the cam cycles once!

450robot
11-12-2005, 09:24 PM
and the examples were not accurate! just depictions of what the setup might look like!

parkers30
11-14-2005, 08:09 AM
you can NOT accomplish a gear reduction through a crank mechanism, you would alo have issues of speed variance as the "rod" went across the top and bottom of the two cranks

426ex
11-14-2005, 08:22 AM
Gear drive timing has been around for quite a while in the automotive world.

parkers30
11-14-2005, 08:59 AM
you can buy aftermarket gear drive kits for quite a few different engines too

bwamos
11-14-2005, 09:04 AM
I'd rather see a tiny water cooled 2 rotor 350cc Rotary engine with a small supercharger for massive low end torque (like a mini RX-7 engine, but w/ super instead of turbo). It should put out 60-70hp with a very smooth power curve all the way up to about 18,000 rpm based on the velocity of the apex seals. Center of gravity would be very very low, and very light. All the benefits of both a 2-stroke & 4-stroke in one package.

redrider05
11-14-2005, 02:15 PM
Originally posted by 450robot
accually, ducati, or some motorcycle company has done the gear drive thing, they had a series of about 8 gears running from the crank to the cam, the bike is in production too, so it must work well

that is called the dezmo system by ducati....its mechanically closes the valves by gears instead of relying on valve springs to close the valves...thats y ducati rev's to 16000 rpm with absolutely no valvefloat