Thread: Pro and con of gear drive timing?

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Yep Thay can hear you coming a mile away with those gear drive.

Geez Pat Mc really no need to get all bent about this. You are an engine builder, you've seen the problems and results...fine...others have had no problems with the gear drive...also fine.

I asked for Pro and Con....and I'm getting it. As for your statement that other engine builders will not use gear drives, or some such, ????. I know several builders here in CO and in WA, that build hi-performance, ie. drag and roadrace, and street engines that use them and some are like you and say no way.

Sorry dude but I just felt I needed to respond...just 'cuz some disagree with you is no reason to pick up your marbles and leave.

I do appreciate your input...

no not mad just do what you want .some guys just do not get it i do guys will run out and buy a ati or rattler fluidampr and slap a gear drive in like a pet jackson in any one that builds stuff to last just do not use them

Pat,

I am not at all suggesting that a gear drive is superior or even on the same level as a good double roller or belt drive. If I were building (having an engine builder build) an engine as a maximum power all out race engine I would certainly not use a gear drive. If I understand correctly, this guy is interested in a bit of noise induced attitude with an engine probably not much over 1hp per cube. I have a hard time thinking that a properly installed quality gear drive would significantly reduce the service life of his "play car" that probably doesn't see more than 5000 miles a year. So what's the big deal?

Every since Jesel came out with the belt drives , I ran them on my pro stock engines, taking off Milodon 3 gear drives----

On my supercharged Chrysler engines for top fua and funny car I ran Donovan gear drives as I drove a Cirello magneto off the back and a Aviad drysump and fuel pump off the front of the cam---belts or chains aren't strong enough for that---however, the blower belt dampens crank harmonics and the oil/fuel pump dampened cam harmonics via hydraulics

However, I would never use a Pete Jackson type gear drive on anything as the are totally inadequate except as a noise maker---the whine tells you right away that the engine wants them outta there---listen to what your engine tells you, after all, don't you love it????

Hurry and vote on the NHRA.com -----

Jerry Clayton
Keeling & Clayton California Charger

Originally Posted by pat mccarthy

no not mad just do what you want .some guys just do not get it i do guys will run out and buy a ati or rattler fluidampr and slap a gear drive in like a pet jackson in any one that builds stuff to last just do not use them

Pat,

Whoa! Are you saying that ati superdamper, the tci rattler and the fluidamper are all bad? I have heard stories on the Fluidamper, but have also heard that the ati superdamper was good-what is your opinion?

Every time I hear one of those gear drive it makes me think the owner is a supercharger "wanna have". And those cars are usually those that have a permanently closed hood at a show.

As far as harmonics failing valve springs - not sure that I can agree to that theory, but I also don't build engines for a living. The gears are in constant mesh, not an interrupted operation nor do they oscillate under driving conditions. They are also partially oil dampened by a constant lubricant bath as well as by the harmonic damper. Valve springs are dampened as well by, again, the oil bath, the iron of the block, the iron or aluminum of the heads, the rockers and pushrods and are isolated mechanically about as far from the timing device as possible, i.e. gear - camshaft - lifter - pushrod - rocker arm - valve.

If there is a good write up with real testing that disproves my discussion - I do want to read it and will "fix" my message above . I also would like to see a good write up about timing belts vs. chains as I think a belt MAY be the best choice.

The best way to get that blower whine is to install a blower. Sounds very authentic.

Originally Posted by IC2

Every time I hear one of those gear drive it makes me think the owner is a supercharger "wanna have". And those cars are usually those that have a permanently closed hood at a show.

As far as harmonics failing valve springs - not sure that I can agree to that theory, but I also don't build engines for a living. The gears are in constant mesh, not an interrupted operation nor do they oscillate under driving conditions. They are also partially oil dampened by a constant lubricant bath as well as by the harmonic damper. Valve springs are dampened as well by, again, the oil bath, the iron of the block, the iron or aluminum of the heads, the rockers and pushrods and are isolated mechanically about as far from the timing device as possible, i.e. gear - camshaft - lifter - pushrod - rocker arm - valve.

If there is a good write up with real testing that disproves my discussion - I do want to read it and will "fix" my message above . I also would like to see a good write up about timing belts vs. chains as I think a belt MAY be the best choice.

Gear meshing is in fact not constant. Nor is it particularly smooth especially in staright cut gears. I agree there is some damping available in the valve train but this viscous lubrication is not effective at the higher frequency bands that the gear meshing will excite, including the audible ones. Here's some introductory reading.

http://www.mitsubishi-motors.com/cor...004/16E_05.pdf

Occasionally I look for more info but it is not easy to find. Regardless I am studied in both mechanical and magetic harmonics and I think Pat is right on this one.

Kitz

Originally Posted by kitz

Gear meshing is in fact not constant. Nor is it particularly smooth especially in staright cut gears. I agree there is some damping available in the valve train but this viscous lubrication is not effective at the higher frequency bands that the gear meshing will excite, including the audible ones. Here's some introductory reading.

http://www.mitsubishi-motors.com/cor...004/16E_05.pdf

Occasionally I look for more info but it is not easy to find. Regardless I am studied in both mechanical and magetic harmonics and I think Pat is right on this one.

Kitz

Thanks Kitz,
I'm printing it and will read later after I crash for the evening. If you have more, shoot a link out.

there used to be something around about Jenkins back about 1970---ran stock timing chains with plastic teeth to dampen vibrations and spark scatter
(pre crank trigger ) oil pumps were balanced to help on the spark scatter

Originally Posted by IC2

Every time I hear one of those gear drive it makes me think the owner is a supercharger "wanna have". And those cars are usually those that have a permanently closed hood at a show.

As far as harmonics failing valve springs - not sure that I can agree to that theory, but I also don't build engines for a living. The gears are in constant mesh, not an interrupted operation nor do they oscillate under driving conditions. They are also partially oil dampened by a constant lubricant bath as well as by the harmonic damper. Valve springs are dampened as well by, again, the oil bath, the iron of the block, the iron or aluminum of the heads, the rockers and pushrods and are isolated mechanically about as far from the timing device as possible, i.e. gear - camshaft - lifter - pushrod - rocker arm - valve.

If there is a good write up with real testing that disproves my discussion - I do want to read it and will "fix" my message above . I also would like to see a good write up about timing belts vs. chains as I think a belt MAY be the best choice.

well the teeth like kit said there is not a constant mesh there is a idlers on the cheap gear drives and the crank when it hit the power stroke is not as smooth as one would think .and NO you not not want any harmonic dampened buy any valve train parts less you want them to fail the springs have enough on there plate let a lone the harmonics from the bottom end the valve train is not made to take up the down fall of poor bottom end contoll of harmonic of a gear drive and belt drive are the best way to go NO harmonics pass thru the crank upper end

Originally Posted by jerry clayton

there used to be something around about Jenkins back about 1970---ran stock timing chains with plastic teeth to dampen vibrations and spark scatter
(pre crank trigger ) oil pumps were balanced to help on the spark scatter

yes the big plastic set are hard to fine and i did the oil pump deal to just was hard to say if it paned out

Originally Posted by 35WINDOW

Pat,

Whoa! Are you saying that ati superdamper, the tci rattler and the fluidamper are all bad? I have heard stories on the Fluidamper, but have also heard that the ati superdamper was good-what is your opinion?

NO not really i just think that it would be dumb worry about as the crank hitting a power stroke it is getting the ratchet job any control vibration or dissipation with a damper is for not if you put a gear drive in sad engine your just not helping it out in the control of harmonics by adding a gear drive .... i have use them all but i have seen the fluidamper hubs crank on blower engines

Originally Posted by pat mccarthy

NO not really i just think that it would be dumb worry about as the crank hitting a power stroke it is getting the ratchet job any control vibration or dissipation with a damper is for not if you put a gear drive in sad engine your just not helping it out in the control of harmonics by adding a gear drive .... i have use them all but i have seen the fluidamper hubs crank on blower engines

O.K., I had mis-read your Post-thanks for clearing it up-do you have a preference on premium Dampers?