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Anyone run a Pete jackson noisy gear drive in a sbc?

66K views 60 replies 32 participants last post by  predator carb guru 
#1 ·
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
 
#2 ·
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.
 
#4 ·
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!
 
#5 ·
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
 
#7 ·
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.
 
#10 ·
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
 
#12 ·
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.
 
#13 ·
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.
 
#14 ·
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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#15 ·
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
 
#16 ·
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.
 
#17 ·
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.
 
#20 ·
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
 
#21 ·
the dyno experiment was done 10 years ago. i didnt save any copies of the groups' runs. there was a significant difference on engines chassis dynoing at 206-280 hp. the groups expireneced as much as a 7% loss in power with the geardrive. they were based on averages of 3 runs. the instructor said that this power loss was due to the gears being spur cut.

the control was a $14.95 cloyes chain. there were 6 groups of 4 students. they didnt have belt drives to try.

willys your information is incorrect. not to be rude. there is more than a 2% loss. spur cut gears act as friction break.
 
#22 ·
gear drive

Not to hi-jack the thread but,,,, Royce i would like to know more about the gear drive in the 6800+rpm engine, I find this interesting.... Did you ever try swapping out the gear drive for a chain or belt???? Let use know some more of the details..... Please.......I have some theory's about this my self so i am curious.

My opinion on any dual idler gear drive is that they are not to be used with a street driven engine that gets alot of miles on them. I have seen the connecting links ( dog bones) stretch in some of them and make problems in the timing department. Some are ok some not, and it does not seam to be one manufacturer.......

I prefer the single idler systems. They are a bit of a pain to get set up but i feel they keep a closer time......

Keith
 
#23 ·
Keith,
I was chasing a problem to where my solid roller SBC (street engine) did not want to rev to where it should. It was not valve float and it didn't miss or anything. Just did not want to rev much above 6500 RPM (was set up to rev 7200+). I finally after research and trying a few things figured the problem was the gear drive. I did switch to a roller timing chain but, ended up breaking a few roller lifter before I got back to the track. I can't prove or dis-prove the gear drive was the problem. From my research they "can" create the type of problem I was having. Harmonics which play havoc with your valve train.

I have run them many times in milder cars/engines and never had a problem (strictly used Pete Jacksons). Currently I don't have an engine with a gear drive in it. The blower makes enough noise. I used to really love the sound of the quiet gear drives and the fact you know they are not going to break, stretch or slip. They are pretty much worry free. The point you made about the cross bar (dog bone) I have never heard of that, I can see where that would cause a problem. One thing about them, they have to be set up correctly. There is some grinding and clearancing that need to be done. Maybe this is why I have never had a bad experience with them. I guess as with everything there are pros and cons: Belts break, chains stretch, etc...
 
#24 ·
spinn said:
the dyno experiment was done 10 years ago. i didnt save any copies of the groups' runs. there was a significant difference on engines chassis dynoing at 206-280 hp. the groups expireneced as much as a 7% loss in power with the geardrive. they were based on averages of 3 runs. the instructor said that this power loss was due to the gears being spur cut.

the control was a $14.95 cloyes chain. there were 6 groups of 4 students. they didnt have belt drives to try.

willys your information is incorrect. not to be rude. there is more than a 2% loss. spur cut gears act as friction break.
Hmmm . . . you should tell this info to all of the the gear mfgrs & ME professors @ all the colleges out there. They will be glad to know this! I don't understand the concept of "spur cut" ( I assume you mean "straight cut" - never heard of spur cut) gears being a brake?? There is no sliding contact, just rolling contact so what is the braking mechanism? 7% power loss in a 400hp engine would be 28hp. This is equivalent to 21,000watt-hours or over 70,000btu/hr that must be rejected by the engine. That's a lot of heat and a lot of waste fuel!! In all of my career I have never heard this concept and I have designed and used many gear drives. Good example is the gear box used in oil well pumping units. Those suckers last 50-100 years with minimal maintenance, under max power running 24/7. Do you have a tech reference I can review?
 
#25 · (Edited)
i dont know what to say.

friction affects hp
2% is wrong, its more, like a 10-15hp loss
your contact theory is missing something


you know friction acts as a break!



so going to a larger surface area brake pad(increases parasitic drag,decraeses rwhp(you can get a 10-15hp loss there too)), how does that affect btu production. i thought that frictions would be filed under pumping losses, and not thermal losses.
 
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