Interesting article

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Sounds like another $800.00 I gotta fork out now, lol
 
A video I came across a while back that may help simplify things for those fortunate enough to go with this setup.
 
I am far from sold on the gear drive. I ran a Milodon on my bb for 16 years. I suffered a lot of valvetrain issues. I can't say for certain that it was related to the gear drive, but the possibility that it was , added to a well known engine builder telling me he has seen power losses everytime one is used has me switching to a belt drive.
 
I am far from sold on the gear drive. I ran a Milodon on my bb for 16 years. I suffered a lot of valvetrain issues. I can't say for certain that it was related to the gear drive, but the possibility that it was , added to a well known engine builder telling me he has seen power losses everytime one is used has me switching to a belt drive.

WHAT I`VE READ , THE GEAR DRIVE TRANSFERS A LOT OF HARMONICS TO THE VALVE TRAIN , WHY DOESNT THE FACTORY USE THEM ??
 
I am far from sold on the gear drive. I ran a Milodon on my bb for 16 years. I suffered a lot of valvetrain issues. I can't say for certain that it was related to the gear drive, but the possibility that it was , added to a well known engine builder telling me he has seen power losses everytime one is used has me switching to a belt drive.
What harmonic balancer were you using?
 
A correctly installed quality gear drive makes zero noise. None. One part of the article I didn’t agree with. I don’t use paper to set the gear lash, I use a dial indicator and it set the lash at .002 and send it. I’ve used them for years on the street and not once has anyone asked if I have a gear drive. They don’t ask because they can’t hear it.

As for the harmonics, I can say I’ve never found an SAE paper or any other peer reviewed article on a fixed idler gear drive transferring harmonics. Not one. I asked a guy on SpeedTalk years ago to show me a detailed paper with an analysis of gear drive harmonics using a fixed idler gear drive and he posted a paper where they tested a chain, a floating idler gear drive and a belt, but nothing on a fixed idler.

I’m open to reading any decent paper(s) on gear train harmonics as it relates to fixed idler cam drives to change my mind. 30 plus years of running them says I’ll never find it.

As for the power loss...I can’t say. You’d need several days on the dyno to sort it out. I do know a friend was running a gear drive and he almost couldn’t sleep at night because he was worried about his valve train getting killed, even though we looked at both our stuff every winter and never saw a thing.

So he sprung for a belt, thinking he’d find some ET in it and nothing. At the end of the year, we took the engine apart and it looked the same. He was shifting at 8000 and it was a stick car.
 
Straight cut gears of good quality, properly setup will run pretty quiet. Not silent, but not screaming either and pretty close to a chain drive. You usually don't hear much from your A833, right? Helical cut gears will run even more quiet, but I have to look into what it would take to implement them. Definitely more expensive gears but I don't know how much.
 
As for the power loss...I can’t say. You’d need several days on the dyno to sort it out. I do know a friend was running a gear drive and he almost couldn’t sleep at night because he was worried about his valve train getting killed, even though we looked at both our stuff every winter and never saw a thing.
I am guessing the more agressive the overall engine build, the higher the POSSIBILITY of damage from harmonics. Like you say, it would take a lot of testing .
I have also changed cams, springs, pushrods in the combo. So there is no way for me to verify anything.
I due run a good damper. ATI Superdamper.
 
I am guessing the more agressive the overall engine build, the higher the POSSIBILITY of damage from harmonics. Like you say, it would take a lot of testing .
I have also changed cams, springs, pushrods in the combo. So there is no way for me to verify anything.
I due run a good damper. ATI Superdamper.


I forgot to mention that for your application the idler gear is in the cover, so that can make a bit more noise than what Milodon calls the “cheater” gear drives that go under the cover.
 
It's my understanding that with drag cars gear drives are not that beneficial when the load is pretty much directly positive keeping the chain assembly tight under acceleration and a small amount of timing variation under low load is not really a concern of mine. Gear drives become more of a benefit when RPMs are sawed back and forth in applications such as circle track racing or similar types of use. Also gear drives can produce harmonics and are less forgiving in their setups. For those reasons I would never really consider one for my application.
 
I disagree with the effectiveness idea you brought forward. A chain, while under acceleration is tight, when it does become loose, the timing of the cam will change. The gear drive stops this. Technically, a gear drive is a win win period. A chain is always a loser, no way around that unless someone invents a completely unstretchable never wearing gear set. It is just a matter of time of when and how much the chain will stretch. Not IF.
 
I have no concerns about what I feel are insignificant timing events changes in the low load. if your road racing or circle track racing it may be an option but for a street /strip nope .if you have nothing more to spend money on than buy a gear drive. But a belt drive would be the direction I would move if I really felt the need to. To each their own!
 
It's my understanding that with drag cars gear drives are not that beneficial when the load is pretty much directly positive keeping the chain assembly tight under acceleration and a small amount of timing variation under low load is not really a concern of mine. Gear drives become more of a benefit when RPMs are sawed back and forth in applications such as circle track racing or similar types of use. Also gear drives can produce harmonics and are less forgiving in their setups. For those reasons I would never really consider one for my application.
So why did Chrysler develop a factory chain tensioner if the chain stays tight?
The harmonics is not proven. As it said in the article, it's an old wives tail.
 
I have no concerns about what I feel are insignificant timing events changes in the low load. if your road racing or circle track racing it may be an option but for a street /strip nope .if you have nothing more to spend money on than buy a gear drive. But a belt drive would be the direction I would move if I really felt the need to. To each their own!
What I don't have money to spend on is bent valves and a broken motor.
My very first car some 40 years ago(Honda civic) ruined the motor when the factory timing "belt" broke and the Pistons hit some of the valves in the process. I would say a chain is more reliable, for a street strip car, but with my high lift cam, I need to know that my piston to valve clearance stays where I set it at. A gear drive is best at that. IMHO
 
A correctly installed quality gear drive makes zero noise. None. One part of the article I didn’t agree with. I don’t use paper to set the gear lash, I use a dial indicator and it set the lash at .002 and send it. I’ve used them for years on the street and not once has anyone asked if I have a gear drive. They don’t ask because they can’t hear it.

As for the harmonics, I can say I’ve never found an SAE paper or any other peer reviewed article on a fixed idler gear drive transferring harmonics. Not one. I asked a guy on SpeedTalk years ago to show me a detailed paper with an analysis of gear drive harmonics using a fixed idler gear drive and he posted a paper where they tested a chain, a floating idler gear drive and a belt, but nothing on a fixed idler.

I’m open to reading any decent paper(s) on gear train harmonics as it relates to fixed idler cam drives to change my mind. 30 plus years of running them says I’ll never find it.

As for the power loss...I can’t say. You’d need several days on the dyno to sort it out. I do know a friend was running a gear drive and he almost couldn’t sleep at night because he was worried about his valve train getting killed, even though we looked at both our stuff every winter and never saw a thing.

So he sprung for a belt, thinking he’d find some ET in it and nothing. At the end of the year, we took the engine apart and it looked the same. He was shifting at 8000 and it was a stick car.
The key word is "fixed idler"
 
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