Friday, August 29, 2008

Bling - Gear Drive



I have to admit that every time I thumb through the latest edition of the Summit catalog I usually flip right past the page that has timing chain sets, gear drives and belt drives. I think that most people are like me in that regard too. Slap a timing chain set on the thing and be done with it.

Well at a swap meet a few years back I found a brand new Pete Jackson “noisy” gear drive for $90. Now I knew that a good billet timing chain set cost about that much so I decided to pick it up.

I first learned about timing gears when a buddy of mine who used to run one on the street referred to is as the “Poor mans supercharger.” The “noisy” gear drives make a distinctive whine that you either love or hate.

Personally I love the sound of whining gears. My 1997 Honda VFR750 had a V4 engine in it that had 2 gear driven camshafts. Man, I loved the sound of that thing running! It was very distinctive, but not in an annoying way.

People will debate all day long which is better, the gear drive, belt drive or timing chain.

Those against the gear drive claim that a gear drive transfers harmonics to the crankshaft which can lead to problems. Pete Jackson told me that if those harmonics can damage the crankshaft, then he doesn’t want to run that crankshaft in his engine anyway. He was basically saying it’s really a non-issue. Some also say that the floating dog-bone style gear drive idler gears can “load” up the system under acceleration causing the idler setup to be forced in one direction while the other gear is forced tighter between the crankshaft and camshaft. The resultant of these forces is that it eats up a few extra HP. I actually believe this theory now, but I didn’t when I first heard it.

Others just say they are annoying.

Those for gear drives talk about the accuracy that gear drives offer. Those people usually love the sound of them. (Me).

That leads me bring up the Milodon Fixed Idler setup. This setup has a fixed idler which does not move so therefore does not have to deal with the same forces that the floated idler design has to. Problem is that it costs almost $400 and when faced with other needed items in the trusty Summit catalog most people skip right on past that page.

Belt drives are the cats meow in terms timing accuracy, and the ability to do quick cam swaps or adjustments. Problem is a good belt drive setup will set you back upwards of $900. Not to mention that they not the most streetable things out there. The idea of an exposed spinning timing belt at the front on engine right where all the pebbles and rocks are flying up gives me shivers thinking about. One racer referred to his belt drive as a vacuum cleaner on the front of his engine! HAHA.

I’d like point out that I think that a timing chain is perfectably acceptable for 99% of all performance applications. The only time a gear drive is really needed is when a fuel, oil, or water pump is being driven off the camshaft and there is a lot of force being transmitted.

So when I ran across a used Milidon fixed idler setup a year ago for $200 I couldn’t pass it up.

Here is a video that I found on Youtube of a Charger with the same type setup I’m going to run.



Just imagine what the sound of that gear drive PLUS the blower whine is going to sound like!! It will be sweet music to my ears. I did tell y’all I’m going radio delete right???

Peace.
WesleyJ
1 John 4:10

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