When I look at gear drives in my Summit catalog, It shows two different types of gear drives. Quiet and Noisy.
I know what a Noisy one sounds like, but does anyone know what they mean by "Quiet". Is it as quiet as a conventional timing chain? Or still noisy, just not as loud as the "Noisy" one.
They also say "Minor machining may be required". Does anyone know what they mean by that?
Thanks, Rich

rich i had a set in a 33 ford roadster i had and they were the NOISY ones ''pete jackson''.i really liked them in it,but as far as putting them in my 69 no,i like the original look and sound myself in something like that.ok as far as the machining you may or may not have to,on the back of the gears sometimes you have to hit them at the grinder just to give you alittle clearance from the block.quiet ones mean just that QUIET.

rich,
from what i've heard, you ought to stay away from gear drives. first off, if one of the gears break, it will jam up everything and could cause some serious engine damage, not like a chain that would just break. second, i've been told they steal away horsepower, because it takes a lot to turn them.
like i said, this is what i've been told by some engine builders and they say to go will a good named double roller or true roller timing set.
later,
bruce

I always go for the quietest Pete Jackson or Edelbrock dual idler gear set I can find, the one still in the box, owned by somebody else who will have the problems it will cause.

If I go gear drive, it is always a single idler, fixed to the block. Summers Bros, Milodon, etc.

Jackson, Edelbrock quiet is one with a small amount of backlash between the gearsets, noisy is one that is pre-worn out, loose and both are pure junk, plain and simple. I am sure the ones you are hearing are actually quiet ones, as they make lots of noise.

For street/mild strip use, do yourself a giant favor and use a good double row roller timing set, and stop believing all the racer and high-zoot ad hype.

I'm going to go with IgnitionMan on this. I have had friends that used the quiet Pete Jackson drives and it was just still too much. After a month or so they would literally give them away. You gain nothing performance wise using a gear drive over a good double roller. My personal thought on this is if my car is going to sound like it has a blower under the hood then it should. I don't want my car to sound faster than it is. I rather have it sound slow. If I lose to a mustang or something I don't want them thinking they beat a old Camaro with a blower. To each his own but just make sure you can really live with it before you go through the trouble. One more thing, don't install a gear drive on a computer controlled car.

hi
my views on gear drives....waste of money. i bought a camaro with a noisy one and it drove me crazy...tossed it quick. go with a nice quiet double roller chain and you won't be disappointed.

I think they were cool about 10+ years ago, now there just a little bit "old school". Go with the timing chain.

Well,

I've used a Pete Jackson gear drive (quiet one) for years now, and I've had really good luck with it. In fact, I'm putting one in my new race motor, which should run low 10's to high 9's. Say what you want, everyone's entitled to their own opinion, but I think some of you guys are bagging on it pretty hard when it's a pretty good product. Just my 2 cents. Take care.

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69 SSRS Frame-off Resto
81 Z-28 377ci Drag Car

See, now, there's words that go together, GEAR DRIVE & RACE ENGINE.

Words that don't are GEAR DRIVE & STREET ENGINE.

Words that don't work, dual-idler-gear-drive, words that do work, single-idler-gear-drive.

Thanks, my opinion and experience.

What concerns me about gear drive is that it provides a solid mechanical coupling of the crankshaft to the camshaft. This does a much better job of transmitting mechanical resonances to/from the crankshaft and the cam than a chain will. Yes, the end result of this may be difficult to measure, however I guess it makes sense to me to spend less money on a quality chain drive and not worry about adding or amplifying resonances in the engine, especially those marketed as "extra noisy"... I don't think you'll find very many high dollar race engines with that feature.

Just my opinion.

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http://www.geocities.com/dmdirks/Automotive.html

harmonics is a very large and valid concern with the dual-idler sets, but even more dangerous is the nooisy ones are set with a pair of idler plates that place the gears farther apart. In essence, noisy drive comes pre-worn out, and things just get worse from there as the plates auger the idler gear pin holes farther apart, giving more and more backlash. Over stresses the valve train and doesn't help damping of the cam to crank interface.

Single idler has idler gear pin affixed to the block or an aluminum timing cover, so the backlash doesn't grow with useage.

Double row timing chain doesn't have any of those problems.

i have a pete jackson quiet geardrive in my camaro. i love it! and it really perked my camaro up. dont know why they get a bad rap.

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BLack 69 coupe 350/TH400 factory A/C

so a street engine cant be raced now? its got to be a race engine to race.

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BLack 69 coupe 350/TH400 factory A/C

You guys that are running gear drives, let me ask you. Why did you decide to go with one? Was it for the sound, more performance? I'm not being a jerk, to each his own, I'm just curious as to why you paid all the extra money for one compared to a roller. The people I know that had them pretty much only bought them for the sound or the hype. Both of which wore out quickly with them. If you run them and like them then great, but why? Teach me something good about them

i like the sound, i had a 2xroller and i junked it for my geardrive, to me the car acts better, its just neat to hear a car with one, because not to many people use them. i was a cruse and a big block mopar came around the corner with one and i fell in love. just another thing to list on my car, bought one becaue i could. i just like them.

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BLack 69 coupe 350/TH400 factory A/C

I'm running one because I'll have about 300 lbs spring pressure on the seat and about 750 lbs open. I like the fact of having a link between the crank and gear that won't distort or give. Maybe I'm stupid, but like I said, I've had really good luck out of mine. People can say what they want, and I'm not telling ANYONE to buy one, I'm just saying they work for me. The backlash that I-man is reffering to is of no consequence, because when the engine is running, the large idler gear is pulled into the mesh. The small gear is under no load when the engine is running. When you turn the engine over on the stand, the large gear is tightened into the mesh. Now, I'm not saying this is better that a single, fixed idler gear, but it is a lot cheaper, and the key for me is that it fits very easily under the stock timing cover. My race engine is reverse-cooled, so I have enough water lines and vacuum pump lines on the front of my motor, without trying to work around the timing gears. I've rebuilt enough SBC with decent spring pressures to know that the chains (even the GOOD ones), get pretty sloppy after a good season at the strip. This slack retards the cam, and I know the gear will never do this. Just my 2 cents. I'm not trying to convince anyone here, just telling you my experience. Take care.

P.S. If some of you have the book "Power Secrets" by Smokey Yunich, read what he says about timing chains. He put a clear timing cover on with a light mounted behind it, then he ran the motor on a dyno. He said something about it looking like a snake above 7000 rpm. He also states that he has used a DIRECT gear link between the crank and cam (turning the cam backwards), and in fact recommends this method. He does state, as I did, that the singled, fixed idler is better than the dual idler set-up. Very interesting reading. Take care.

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69 SSRS Frame-off Resto
81 Z-28 377ci Drag Car

[This message has been edited by 69SSRS (edited 08-03-2000).]

Of no consequence...Oh, really?? Well, thinik about this, EVERY Pro-Stock engine used today is running either a Jesel belt drive or a common duoble row timing chain set, every one. What the actual real racers found is that the gear drives actually had too much harmonic distortion transfer from the crank to cam and valve train.

Now, Pro-Stockers run cams with between .900 and 1.100 valve lifts through the rocker arm ratio, and $1,700.00 a set titanium valve springs they change in 15 runs. When these same valve trains were run with a non-daqmping timing system, the valve springs lived 7 tp 8 runs. Since a Pro-Stocker is normally aspirated (PULLS mixture into the cylinders), harmonics is a very important issue, as it disturbs the intake flow and carburetion/jetting.

Dual idler gear backlash is seen as the engine is on steady rpm output, and at deceleration, and allows the cam and valve train to chatter and have erratic operation, even in acceleration mode. This ain't good for notin' in the valve train, and is vitally consequential.

As the dual idler jobs get loser, the amount of harmonics and vibration gets more intense, with growing adverse effect. Eventually, the idler gears get so loose the contact of the teeth get twords the limit of strength, and the teeth begin to chip and will fail shortly after this.

There were lots of roundy-round racers in Merced, where I had a speed shop, and they drive of choice was the Junkson dual idler nightmare. The cars that consistantly won came from my oir another shop, and always had chains on them, the ones that always had cam, rocker, spring, valve train problems used the dual idler junk. Once the racer saw the light and went chain, he began to get a season on a chain and sprocket set and began to not have the valvetrain problems and could actually tune the engine, something that wasn't possible with the gear drives.

Blower alchohol and nitro engines run gear drives, but they only use cams with lifts through the rockers at or very near the .700 levels, and, since they vibrate the daylights out of themselves, not much damage is done from them as far as harmonics. Since the mixture is pressurized into the cylinders, the harmonics become moot in those supercharged powerplants.

Of no consequence-for a normally aspirated engine?? Makes every consequence, bet your life it does. Ask any real and knowledgeable cam or carb person about distortion and the prblems it causes in the valve train and/or intake tract, you'll hear the same thing, vitally important not to have any. You won't hear any of the real truth in the big-time hype ads for this junk dual idler garbage.

Quote from before: "People can say what they want, and I'm not telling ANYONE to buy one, I'm just saying they work for me."

I was asked why I ran one, and as a courtesy, thought I would answer, but should have known I would get bashed for my opinions.

I don't like nitrous, but you don't see me bashing every guy that likes to run the stuff, do you? To each his own. You run what you like, and I'll do the same. Until someone donates over $500 to my racing fund, a belt drive is not #1 priority. Sorry if that bothers you, but I'm not Warren Johnson, and never will be. I'm trying to build a $20,000 engine on my own income, without any sponsorship or donations, so I do what I can. Take care.

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69 SSRS Frame-off Resto
81 Z-28 377ci Drag Car

69SSRS, nobody, including me, is "bashing" you. Just relating FACTS about the dual-idler gear drives and their problems/drawbacks from over 30 years of fighting with Pete Jackson and pleading with him to make them better, without any positive results.

Now, it seems to me that if you have to defend the drive simply because you bought one or haven't used it hard enough to make the problems many, many others have had, then that is your problem, not anybody else's.

I posted proven facts, you countered by saying my findings were inconsequential, I responded with more PROVEN FACTS, and you couldn't handle it, so you say I'm bashing you, not even close.

The facts I posted weren't all just moine, but well over 500 of other people's Pete Jackson/Edelbrock dual-idler drive experiences, and mine.

Sorry you felt bashed, you weren't, FACT.

I was just curious as to why people used them as most I have known didn't like them. I appreciate the responses from 69SSRS and IgnitionMan and didn't want nor expect it to go this route. I am sure each has its own advantages and disadvantages in different situations so I wouldn't think either is wrong. Is a three inch dual exhaust on a straight six Camaro a good choice? No of course not. But great on a 502 blower motor in the same car. I put down the gear drive because I don't see a need for it on a street driven commuter car. Maybe up to some level the gear drive is good and past that level to a all out racer the belt drive is the way to go. I really don't know. Price and usage have to be two big factors. If belt drive is so good then why doesn't the manufacturers put them in from the factory. Its probably because its not cost effective or overkill. Not because its inferior to a chain. I have to believe your both right to some extent and not that you have to go with one or the other or your making a big mistake.

Belt drives are used on plenty of engines produced today, overhead cam engines, foreign and domestic. Great way to do a cam drive, but none are produced in mass quantities for earlier pushrod american engines, and yes, the Jesel drive is really expensive, but well worth it in a racing situation.

A single idler gear drive is much more accurate, will live lots longer and perform much better than a dual idler setup, that's why the fuel and alchohol people use a single idler plate mounted gear drives only, and they buy and use what works. They don't use dual idler stuff.

If a roller chain or a direct drive breaks there can be alot of damage, like valves smacking pistons. Bob

And, when a Junkson dual idler drive breaks, the same valve damage happens, and you get the luck of breaking the front of the cam off as well, and all that gear scrapnel in the bottom end past the front main cap. MMMMM, let me run right out and get one, they're soooooooooo good-NOT.