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Discussion Starter · #1 ·
has anyone used a gear drive on their 289/302. i have installed one, yet to start the motor, but am having second thoughts. is the gear drive good up to 8000? or is 8000 just too much? i'm thinking maybe i should just install a chain, which i know will work.
 

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The only thing bad about a gear drive, it creates unwanted valvetrain harmonics that can cause bolts to back out, and valvetrain wear (worst case-scenario, though). Especially if it is a noisy one, the quiet ones don't cause as much, but still do. I thought about one for my 357C build, but I searched the internet for oninions and possible problems, and I finally decided to go with a double roller.
Hope this helps, Chris.
 

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Gear drives work fine at high rpm. they dont stretch and flex like a chain so your timing is more accurate. A gear drive will actually keep the "spring" actuation from causing hamonics in the crank. That means those forces are contained in the cam. Each time the cam starts to open a valve it wants to slow down and when it starts letting a valve close the spring forces want to speed up the cam. Those harmonics are partially absorbed by the gears and what doesn'y get absorbed get "bounced" back to the cam. Those are the harmonics that are usually transferred to the crank but with the gear drive they get sent back where they come from - the cam.
Paul
 

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Discussion Starter · #4 ·
thanks for the info chris and paul. ken
 

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ive been using one on a 351w for afew years with no problems
 

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I have personally torn down 2 sb with gear drives for the same reason..... CRACKED CAMS !!!!!!! Be warned that this happens with the noisy drives
 

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I`ve had a pete jackson gear drive in a 302 i ran for 12 years and alot of abuse. I turned it 7500 rpm,s with a 125 shot of spray. the only thing i heard bad is that gear drives rob the most power, a Danny bee or Jesel belt drive is stronger than a chain and absorbs more harmonics and robs the least power. HOPE IT ALL WORKS FOR U WHATEVER YOU DO.
 

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Actually, gear drives can send harmonics from the crankshaft to the camshaft, which is why they have fallen out of favor with most engine builders. Belt drives offer the best of both worlds.....accuracy of a gear drive....crank shaft harmonic isolation of a chain. Not to mention the ability to advance or retard the camshaft without engine disassembly. Oh, and belts are very quiet. Even so called "quiet" gear drives are pretty dang noisy. Of course I happen to like the noise

<font size=-1>[ This Message was edited by: carsnguitars on 3/1/07 4:42am ]</font>


<font size=-1>[ This Message was edited by: carsnguitars on 3/1/07 4:45am ]</font>
 

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Gear drives are just noisy things. Lots of people go plenty fast with a good chain. No real harm except having to deal with the disappointed faces that appear when you drive up, open the hood and people don't see a blower (because that's what it sounds like).
 
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