#### BINGO we have a winner !!! Refer to post #7 on harmonics !!! This would be the exact gear they used as I have a few left in my stash !! Cushions the valve train harmonics and it did one other thing to the cam timing that some guys figured out a few years later on the dyno !!! Funny thing was Grump never admited to the dyno thing or the nylon gear !!! >>>>.
yea not going for the blower sound(been saving for that "sound" for along time) to me they sound nothing the same, that would be like saying an m22 is the same sound as a GD or a blower to NOT POSSIBLE.So is the drop in horsepower a thing thats really noticable or is it overstated as im starting to understand the "suicidal gear teeth" myth was hahaha i was just wondering because you got to always go through the process of any part that can go in you got to know whats what about it(And i respect the crap out of most of you really giving Props to DirtyThirty An Homespun91 as they have helped me alot since i came here)
also i heard the more accurate stability.....of course the Pete Jackson is the only one i have considered(heard the procomp ones arre Complete Crap)
Brad, Some neat trivia from Lamar. Actually, the Morse-type chain is metal...the cam gear is nylon-coated aluminum. You are correct...back in the very early days of P/S a lot of guys did run them, and for that reason. It was fairly common practice in NASCAR as well. Though they have an evil reputation for shedding the nylon, it being collected in the oil pump pickup screen as a rule, that wasn't an issue for racers. At the time I believe the sets were around $12.00. They were just basic GM SBC timing sets for a pre-'68 application. I used to see them almost daily, but it's been quite a while now. I have a picture of a Booth/Arons Pro Stock BBC with modified stock pan/pickup, a stock GM timing set, and so forth...really nothing exotic at all. The Australian Rollmaster sets (made by Romac) are good pieces; I'm guessing that's the brand to which he was referring.
I've used them both. As previously stated - Quality of the product and correct installation are the real factors.
I worked on an acquaintance's engine a while back...he wanted a gear drive & bought one of the cheap ones, against my protests. After sending three units back because they were too inaccurate to run, he finally switched to something better. So far as helping ya lots...you DO realize that I'm quite insane... Must have been all the, er, "chemicals" I ingested in high school...hops...barley...
Yeah, that's the one--I was close! I do remember Lamar saying they were like $12 or $16 or something stupid. I don't remember the name of the Aussie chain set he's recommending, but I'll find out tomorrow when I head down there to work on my engine. -Brad
Smokey Yunick talks about making a see-through timing cover to observe a timing chain in action. He couldn't believe how much it moved around at speed. He said it wiggled around like a wild snake trying to get out of a hot oven. He said he could see no reason whatsoever to use a timing chain in a racing engine. They used a two gear set-up, but had to use a reverse rotation camshaft. (try finding one of those) I'm sure NASCAR banned that since smokey used it.
So what exactly are we talking sound wise between the Loud an Quiet? i am not really going for that sound to be noticed but i know its pretty impossible to hide it so should i go all out if i do or?......still thinking about a double roller though, just heard a gear driven big block the other day and it was one of those "mine could sound like that ahhhhhhhhh sweet" kinda things just go to think it through
BIGCHUCK, you can still have one of those f-uped cams ground$$$$. They are called half speed cams or some BS. Good for nostalgia talk.If you find one you will have to change a suprising amount of things to work. Everything has its place. In this case a double would do you fine or if you like the noise, gear it.
the loud dual idler gear drives have the tie bar (the piece that holds the two idler gears) machined really sloppy. this lets the idler gears rock around and try to "steer" as they roll. this makes alot of noise. the gear drives actually introduce alot of noise and harmonics and bs into the system that will completely screw with the knock sensors of newer cars. the rubber belt drives use the least amount of HP and absorb harmonics but are too much price too much racepart for a daily driver. link belts are quiet and rugged, double rollers louder but really rugged (just make sure to soak your chains before installation. (i like the grooved front bearing trick- small block mopars have a drilled bolt that oils the chain) ALSO remember your front tin will let it be noisy (stamped steel) or quiet (cast aluminum timing cover).
I put a pete jackson loud drive on my mill bout 15 years ago...just did a rebuild on the engine when it was ot and no metal shavings....it was in perfect health.... HOWEVER....the noise got old and has been old to me for the last 10 years....yeah it was cool at first...but as others said....it''s the wanna be way out if you want to sound like your trying to have a blower.... I pulled it out and slapped on a cloyes double....I have a feeling I'm gonna like that a whole lot more.
Squig I use a cloyes gear drive and I am very happy with it. But let me warn you about cheaper units. Only Cloyes and Pete Jackson are heat treated !!!! I started out using a Edelbrock in my roadster, 306 SBF - Edelbrock Heads and cam - Early Ford factory 2x4 set up. The first gear drive form edelbrock broke the crank gear in 3 pieces at 75 mph. That only cost me 8 valves and 4 pushrods as well as a gasket kit. The second Edelbrock unit cracked one of the idlers. Talked to my machinest and he said the reason was they are not heat treated!!! This may be the reason other folks have had small pieces show up in the pan. So far after 8000 miles I do not have pieces or any wear on my gears. My buddy has a Pete Jackson in his coupe and it has around 40 k miles on it with no problems. Also I think Ford flat heads used a gear drive 44 t cam gear and 22 t crank gear but they were not straight cut gears. PS I like the noise !!
This is a good thread. I've always wanted a gear drive setup, yes for the noise, no they don't sound like a blower. But a nasty cam, fenderwell headers, and a whiny gear drive sounds like music to my ears. But if they rob that much power, then that's something to consider. I also never thought about the harmonics between the crank & cam, so now I'm thinking a gear drive is not worth the possible problems down the road. Ah, who knows, to each his own I guess.
If I wanted the sound of a gear drive I'd just run the power steering dry, same sound. My vote is for double roller, live long time, no annoying whine, no haromonic issues.
Double rollers and metal gears have been around a long time. I don't think it's aproblem. Been using belt drives for a while. Don't know what the life expectancy would be on the street though.
Have had a Gear Drive in my 350 SBC for 5 years and I love it !!! But I'm just a Poser !!! LOL. Tom (Tired old man)
Ya...I know...just funnin'... Maybe someone out there knows, now that you, and I, mention it, exactly what one might get mileage-wise out of one of the belt drives in a street/daily app.? I'm curious... I remember when they came out it was DEF. some of that "race-only/not for highway purposes" shit. And, just for the record, if it helps ya' Squig: The drag truck has the gear drive, but...my Ranchero, on the street, shall retain a chain... The truck motor has had one for years, way before it was even in the truck I have it in now, and has not failed, however, honestly, if I was building anew for the street, I'd use a chain, too...In the case of the truck, if it was not there now and I had to choose???? I guess I'd do a cost/benefit analysis on the three.... But, either way, a GOOD gear drive unit is not going to let you down...except maybe financially... Don't buy PRO-COMP ANYTHING!!!
I really like the adjustability of the belt drives. I really wish I could get one for a Nailhead. It's be nice to be able to play with cam timing that finely.
gear drives ..I've run them for 25 years .. if I was getting metal shaving in my oil I never saw them ....
I have a gear drive in the wifes hot rod truck, sbc, going on 11 years and about 56,000 miles and no problems as of today, she drives it about two times a week to work, I have not seen any metal shaving in oil at change.
Funny, I was just discussing this with Spartan last night regarding the Desoto Hemi we're putting together. Upon exposing the timing setup the other day I could not BELIEVE how much slop was in the chain, a motor with just under 70,000 miles upon self-destruction. I could pinch both sides in with my pinkies about a half inch or more at the same time! A little research has shown that this was a common problem with the Desoto Hemis because of the longer cam gear off the end, too much stress. Now, granted, a brand spanking new double roller from a reputable company has got to hold up better than the stock chain did, but would it be safer to run the gear drive? Or is that adding even MORE stress and harmonic problems to an already overstressed cam setup?
Nothing wrong with a good gear drive, just dont get the cheap ones, because they dont improve timing, you have to go with an expencive one to get any benifits
20 minutes on the street with a noisy geardrive is like slowly turning a corkscrew into your brain. It sure seemed hardcore when you stared at it on the stand..........but living with it is a whole nother thing.
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