|03-05-2013 01:39 PM|
|lg1969||Many years ago I had double roller chain in my 350 and after one year of driving it, the chain was loose. That was only a year of use. That's one reason why I switch to gear drive. I never had any problem ever since. And that same gear drive is in my 406.|
|03-05-2013 12:25 PM|
"Noisy" gear drives are for the "Hey! Look at me!" crowd, they are not for performance. The Milodon is a REAL "race" piece. The Pete Jackson (dual idler) is pretty tough. We had 300-plus seat pressure in Dirty Bird and used the Pete Jackson (the Milodon for the Pontiac would take 6 mos. to get). We had exactly zero issues. 9,200 RPM each pass. It wasn't the "added noise" unit, of course. That engine uses "roller" cam bearings as well.
Gear drive has its "place". High-end racers with serious spring loads can benefit. One piece of advice given me a long time ago, NEVER use a gear drive if you have a two-step or "stutter box" for bracket racing. it can break the gears. A belt-drive is the "way to go" there.
|03-05-2013 10:14 AM|
The floating idler gear drives may not be a good choice if you have a lot of valvespring pressure, as the bigger idler gear is trying to wedge itself between the crank and cam gears. The harder it is to spin your cam, the worse the wedging force will be. The front cam bearing will show a lot of wear up top, in severe cases the cam can actually bend. A bigger idler gear would help, but these things are usually limited by the designer's need to use a stock timing cover.
In my experience with an sbc/solid roller (200 lbs on the seat), the cam didn't bend but severe front cam bearing wear allowed the cam timing to retard quite a bit. Luckily i had plenty of piston to valve clearance. A simple change to a timing chain and the car picked up the several tenths that it had lost. When the geardrive was removed, the idler gear axles/bushings were quite sloppy, had about .100" of clearance.
|03-05-2013 08:59 AM|
I have my gear drive for over 20 years and never had any valve train failure at all. Have travel from Long Island to Maple Grove Penn. and far north to Mass.
The noise level I hardly hear it while driving once the motor is warmed up. I Love the sound of it.
|03-04-2013 10:56 PM|
|KyleG||I looooooooooove mine. It's noisy. Family says they can hear it coming before anything else. When driving though, even after a few hours, it doesn't bother me.. At all.. Dont really notice it unless pointed out. Although, driving something without one, I just feel, empty lol Just a natural sound to me now I suppose.. Very snappy throttle response.|
|03-04-2013 07:57 AM|
|03-04-2013 07:36 AM|
|33Willys77||I have a Milodon in my Hemi - has a fixed idler gear. My timing stays put throughout the RPM range. If I run the engine without the blower belt, I cannot hear any noise (from the gear drive). The noise comes from the design of the teeth, just like a blower belt. The air is getting pushed out between the teeth creating a noise. It all depends on how the teeth are cut and how the gear drive is designed and installed. I would not run a dual idler gear drive, but with a fixed idler, I see less slack than I do with a chain.|
|03-03-2013 08:58 PM|
|Actionjk||Iv'e had a couple of them in my cars,can really only hear them at idle and up through the gears,once in high gear you really don't even know it's there.|
|03-03-2013 08:39 PM|
|KA67_72||I have one in my 59 Chevy PU. It sounds good but it's too much. If you're under the hood listening for rattles you can't hear anything over it. David Vizard says they are power robbers. If you like the noise put one on. I can't tell you how many times I've had someone ask if it was a gear drive or a blower and I had to say gear drive. If I ever swap the cam out of the motor, I'll be installing a chain.|
|03-03-2013 07:26 PM|
|03-03-2013 05:23 PM|
|BOBCRMAN@aol.com||About the worst thing you can put in a small block|
|03-03-2013 05:20 PM|
I have a gear drive as well as a blower. No problems after 20k miles. The gear drive really doesn't make a lot of noise. Kinda rattly if anything. The blower whines when you step on it.
I've checked the timing dozens of times and it stays rock solid.
I haven't adjusted the valves in a couple of years.
|03-03-2013 03:49 PM|
|LATECH||I would rather hear dem pipes.... but thats just me.|
|03-03-2013 03:42 PM|
|ap72||Don't forget your distributor is driven off your cam...|
|03-03-2013 02:39 PM|
|68NovaSS||I don't believe valve train failure or noise to extremes is the issue with gear drives so much as harmonic effects I've heard complaints of.|
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