Gear drive for camshafts

[tkelly27]

http://www.maritime.org/fleetsub/diesel/img/fig3-30.jpg

Has anyone made a solid gear cam drive system for DSMs? Anyone even tried? I searched but all I found were transmission gear drive systems.

I started thinking about it when my cam belt skipped a few teeth the other day.

Pros: No belt to break, stretch, or wear out. No tensioner to replace. Easier removal of head without timing loss. Likely they would have built in adjustability.

Cons: Heavier. Might require that they are in constant contact with oil (bringing on a whole new set of problems). Gear whine (which could be a positive). The big bad one, high cost.

Here's a simple set for a SBC
http://www.rpmcat.com/images/DYNAGEAR-78410.jpg

The cost thing. I see high performance belts going for $100-150. You still need the tensioner, and you're still going to have to replace all of it in the future. It's not something I can't do, but if someone made a more permanent solution.

I haven't really seen anything about the reliability or life expectancy of gear drives, but the piece of mind that, when made properly, they physically can't jump teeth is enough to get me to do more research on the subject.

Thoughts?

 

[Quasimondo]

Gear drive setups can only work with OHV engines because the camshaft is very close to the crankshaft. With OHC engines, this is impossible to do, and if you've ever poked around old junkyard OHC engines, you'll see that every one of them drive the cams by either a belt or a chain. It would make more sense to try your hand at a chain driven setup, but with having to customize cam gears, oil and crank gears, tensioner arms, plus find a way to keep the chain lubricated, it doesn't make much sense to rework something that will last a long time when properly maintained.

 

[tkelly27]

You get the parting gift.

Actually a vast majority of the very first DOHC engines were gear driven.
http://www.milleroffy.com/junior_special_gear_drives_web.jpg

which were also actually the very first "tuner" cars (relatively (for that era) high power, relatively (again, for that era) low displacement, DOHC inline 4 cylinder engines), which later even became the very first turbo "tuner" car engines. They were American too, and all started back in the teens/twenties. As they evolved in the (1960's I wanna say...) they started going to belts, but eventually they were making in excess of 1000hp and could not find belts that would stay together for a race and actually went back to gear sets. I'm not planning on making 1000hp, and there are belts nowadays that can stand up to that, but it's kind of a "isn't that neat" factor to it, and straight cut gears sound sick!

Timing chain setups break and skip teeth as easily if not more so than belts. All the ones I've dealt with anyways, especially the '70s plastic toothed quiet drive pieces of trash. You still need to cut the gears for that as well.

Keeping it covered in oil is really the only thing that scares me. I've not done enough research to know if they really even need that, or if special metal or a treatment could be done to them to keep them happy without oil.

 

[knighteclipse1]

It would be interesting if someone ever came up with a chain driven 4G63. Although that is alot of wishful thinking, it still would be tight.

 

[Defiant]

We used to dream of putting a belt on the Datsun 2000s, to free ourselves of the 30,000-mile cam chain life.
It's always the other side of the fence.

No, no one will be putting gears nor chains on a DSM motor. Neither are as good as belts.

 

[lusk219]

Just wondering if this is possible, and if so, how hard it would be... Any thoughts?

 

[VelocitàPaola]

No, it's not possible. For one, you would need to make all the parts yourself. Secondly, timing chain systems are typically built inside the engine block for lubrication purposes. So unless you're willing to cast custom blocks, it's out of the question. Timing belts are reliable enough, as long as you change them at their recommended service intervals.

 

[Defiant]

Come on, grow a pair, man-up and stop being a psussy. What could be tough about it? Even better, steal NSU's Ultramax scheme and use eccentrics and rods.

 

[Jeff99GS]

It would be interesting if someone ever came up with a chain driven 4G63. Although that is alot of wishful thinking, it still would be tight.

Its Not a 4g63 but the new 4b11 Lancer/Evo/Hyundai engine uses a timing chain. It has an oil squirter to keep it lubed all the time.

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[RotaryAE86]

No, it's not possible. For one, you would need to make all the parts yourself. Secondly, timing chain systems are typically built inside the engine block for lubrication purposes. So unless you're willing to cast custom blocks, it's out of the question. Timing belts are reliable enough, as long as you change them at their recommended service intervals.

not impossible, almost anything is possible of you have the money/ingenuity to back it up