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CLICK ON MY AVATAR
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Anyone run a Pete jackson noisy gear drive in a sbc?I'm thinking about getting one for my nova.I love the sound of gear drives!Can You tell me your of the pete jackson gear drive?Another question...There are two drives a noisy and a quiet.Can you still hear the quiet one?THANKS BM
 

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gear drives

Pete Jackson is as good as any of the others. I question your reason for putting one in though. Gear drives do keep your cam timing very accurate, but they are a little on the pricey side, and the noise can get tiresome after a very short time of driving with it. If you are going to go with a gear drive, go with the silent. Even most of the silents still make enough noise you can tell its got gear drive, yet the noise doesnt get so overbearing.

If this is a daily driver car and you make long trips with it, you will find that the "noisy" ones can cause you to wind up with headaches from the high frequency.
 

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My Milodon Gear drive in my BB mopar is pretty damn loud- I can hear it over the open exhaust- but it is cool, it almost drowns out the noisy fuel pump LOL
 

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I dont care for any of the dual idler drives as they have a tendency to not be very accurate as far as cam timing. The last one i checked had 7 degrees of movement in the gear lash. If u get one get a fixed idler one. The only thing Pete Jackson i like is their barrel valves and of course Pete himself!
 

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I have the noisy one in my nova....it is quite loud....I liked they way they sounded to...but I had never road in a car with one....do that first if you can....they sound better going down the road, than they do setting in the car going down the road....

If i had it all to do again I'd go with the quite version.....or a good chain...

nasty
 

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I'm using an Edlebrock gear drive in my blown sbc and it is supposed to be a little louder than a quiet Pete Jackson but not as loud as their noisy one. I like it
 

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I'm running a set of "noisy's" on my supercharged sbc too. They are loud, but heck, I wouldn't have a roots blower if I was worried about the wine. A lot of guys will warn you about damage from the harmonics of the gears over a good chain. I'm sure there's truth to this, but I'd already purchased the gears at by the time I started asking questions. If your going for longevity, I'd definitely ask a few more questions from those "in the know"about harmonic destruction before making your choice. Outside the preference for the sound alone, there probably isn't much benefit to running a double idler type gear over a quality double roller chain.
 

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A friend runs a quiet Pete Jackson gear drive on a 350 in his '66 Malibu. It is definitely noticeable, even over the Flowmaster exhaust. If I were to run a gear drive I would definitely opt for the quiet model.
 

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I have run both the quiet and the loud. The queit is very noticable and more than enough noise. The loud is pretty obnoxious after a while (driving). In either case there are some mis-conceptions about them, one was mentioned earlier about harmonics. They do not "create" harmonics and all engines have harmonics. What they "might" do is tranfer the harmonics from the crankshaft to the valve train. This is really only an issue if you are turning 7000 or higher RPM. At lower RPM's it won't have any noticable effect. I have an engine that has had a PJ quiet in it for over 7 years and is still just fine.

I chose to go with a billet timing set in my blown engine because the blower makes enough noise.

Royce
 

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So the quiet sets make enough noise to notice over the engine? I am looking at some as well. I dont want annoying levels of sound from them but I'd like something definitely noticeable.
 

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i posted my addvice about this in the past. there is something nobody is talking about. there is a power loss everywhere in the band with a gear drive system. you are increasing your frictional losses. i m not gonna even start about spur cut gears compared to a roller chain. the skinny

timming gears = power loss. i was able to see the results of a dyno experiment 1st hand. they dynoed the combos with a chain and then gears. this was on 5 or 6 different performance engines.
 

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I recommend the Edelbrock noisy set too. We installed one on the SBC in my friend's '42 Willys pickup and it has been going strong for over 10 years. It sounds great on the outside and with a little care in well insulating the cab, it isn't noticeable inside. They (he and his wife) drive that little truck on really long trips (i.e. 500 miles) very comfortably.
 

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I've had one in my show car for 14 years and I like it. Of course it's not a daily driver, if it was, I would have a belt drive instead.

Troy
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spinn,
Where in the RPM band was the loss? How much of a loss was there? Were these back to back tests with the exact same engine on the same dyno on the same day? I am not doubting you I just want the facts.

I have run gears drives in several engines and never had a problem (for years on end). The only time I even thought the gear drive was a problem was in a high RPM solid roller engine I had. I thought (and still think) that it was limiting my RPMs due to transfering harmonics to the valve train. The "problem" would only happen near 6800-7000 RPM (SBC). After the fact I am not so sure that was even the problem. In either case in a high RPM application (7000RPM) a gear drive would not be my choice. Otherwise on a street car I don't see a problem running them. This is one of those topics that people will never agree on. You either like them or you don't.

Royce
 

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Though I dont have any information to back it up, I've always heard the opposite of what Spinn has said about power loss. Well, not quite the opposite but simply that there isn't really any power gained, but on the flip side no power lost either.
 

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I have no reason to doubt spinn's power loss contention but I do disagree that it is the result of friction in the gears. Friction loss-wise, gears will beat chains every time and twice on Sundays.
Buckingham (Spur Gears, McGraw-Hill, 1928) is pretty much the industry standard on spur gear efficiency. Their estimate is that a typical spur gear pair will suffer ~1 % power loss. Various studies put the range from less than 1/2% to as much as 2%, All depending on tooth pitch, gear ratio, lubrication effectiveness, etc. However, a study done in the 30s @ the National Physical Laboratory, UK puts roller chain maximum efficiency @ 98.6% and that in a very controlled laboratory environment. In comparable drives, a spur gear will always be slightly more efficient than a roller chain. Just fewer things rubbing together!!

Also remember, those efficiencies are of only the power being transmitted through the coupling, gear train power, which is a small fraction of the total engine output. You need to add two gear meshes and a ball bearing for the idler gear which will degrade the gear drive somewhat but at worst chain and gear drives are probably so close to equal that the difference isn't remotely measurable at the dyno brake.

Has to be some other dynamic causing the loss.
 

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[email protected], I agree, well said.

There are a lot of misconceptions about gear drives, I don't know why.

Royce
 

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Reher-Morrison's lower engine assembly manual states a gear drive costs about 15 HP in a Pro Stock motor and should be used only when strength is a priority over power, ie a Top Fuel motor.
 

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Fastnuf,
How much HP does a "Pro Stock" car/engine make? I bet if you compare the percentage it is VERY small. The statement you wrote says it cost them "about" 15HP, my question is compared to what other option? (belt, chain). Do they mention how much HP a chains cots compared to a belt?

Royce
 
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