Gear Drive instead of timing chain

[89240sx]

Anybody know if they make a gear drive for our car instead of replacing the timing chain you can replace the chain with a gear drive setup?

I know it would be louder but probably more reliable... anybody have input?

EDIT: specifically on the SOHC ... also some info here --> http://www.sdpc2000.com/cart.a...=3088

[MrFox]

Gear drives are for pushrod engines - the cam is a lot furthur away in an OHC.

[89240sx]

ohh ok.. thanks

[corn322]

I've thought about this too, but yeah, the gears are pretty far apart. you'd have to have this big long crazy gear train to get the rotation up there.

[MrFox]

Gear drives are for pushrod engines

I'm retracting this statement.

Angular bevel gear drive for overhead cam. Sorry for the crappy quality.

[89240sx]

so is it possible? Sorry i'm not sure... and that pic is pretty bad

[chrissa]

so is it possible? Sorry i'm not sure... and that pic is pretty bad

Yeah it's possible. Honda for instance uses it in their V-Twin motorcycle engine they put in the RC51. Now, the cams are closer to the crank in the 1000cc twin than a KA24E, but not by much (comparing stroke and rod lengths in the two service manuals, Id say around two to three inches).

Honda did this with a cartridge of three gears stacked end to end that slides in between the gears on the crank and cams. There's two cartridges, one for each cylinder.

Normally Honda uses a timing chain in all their high performance motorcycle engines, but in this case a chain wouldn't work. They would either have to run two chains , one for each set of overhead cams (which now requires two drive gears on the crank), or use a big serpentine chain which I'm sure would put all sorts of extra parts and stresses in a deign like that. Neither solution is very compact.

So, out came the gear driven cam design. One crank gear can drive all four cams at once.

The only other consideration to this design is a way to keep tension on all the gears like the tensioners we have on our chains. Each cartridge looks like it has three gears in it, but actually it has six gears. Each gear is actually two gears sandwiched together with a spring between then trying to twist them in opposite directions. That keeps tension on them. Though there's a popular mod to remove the tensioner gears thinking that they rob power from the engine. Guys have been running 2000 models for a while with no ill effects. That mod would make me a little nervous, so I'm keeping mine. Here's a picture from an online microfiche:

[GroundZero]

hmm... wish i had one of those physically in my hands... i'd modify the design to fit on the ka and test it on my car.

[chrissa]

hmm... wish i had one of those physically in my hands... i'd modify the design to fit on the ka and test it on my car.

Wow. I hope I never have to replace one of those cartridges in my bike. They are listed at $381 US each. And there's two of them in there...