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View Full Version : Double Roller vs Gear drive



protour_chevelle
12-12-2004, 10:13 AM
Simple question. Which is more accurate as far as timing goes? Its going into a high end Pro-Street (street legal too) straight line car.

Thanks,

-Matt

Matt@RFR
12-12-2004, 11:06 AM
If you want accuracy in a "high end" motor, use a belt drive! Gear drives are ok, but transfer harmonics like a champ, and can beat up bearings and the like. I wouldn't even consider a gear drive in anything but a sprint car (no balancer, either) or anything else that you're ok with freshening up every 3000 miles.

protour_chevelle
12-12-2004, 11:58 AM
Thanks Matt

-Matt

Zefhix
12-12-2004, 12:23 PM
That's too bad because I really like the sound of the "quiet" pete jackson gear drive in a BB....

ProdigyCustoms
12-13-2004, 02:53 AM
Gear drives suck. Only hurt a motor. Belt drive s are great, but a good tru roller is fine for mear mortals, get a hex adjust if you are degreeing you cam, makes life simple.

Lowend
12-13-2004, 07:05 AM
I have never found any benefit to a Gear Drive... you will notice that you never seen them on pro-racer cars.
Personally I don't think a belt drive is really needed either in most situations. The minor variances in valve timing that can come from a timing chain are not signifigant enough to make a difference. If you are worried about those variences than you need to worry about flex in the rocker studs, variations in the castings of rotors, twisting of the camshaft underload.... you get my drift.

A good old Double Roller Timing chain with a Torrington bearing is pretty hard to beat

AQK1
12-13-2004, 07:51 AM
We just finished a engine build - install in a 67 elcamino. It was a 468ci full roller valvetrain, aluminum heads. dominator carb, etc. The guy just had to reuse his geardrive from his old engine. I would never put one on any of my cars the geardrive was VERY loud and would interfer with any engine diagnosis as far as noise was concerned.

I did not like it at all. In my opinion it detracted from the cars appeal, you could barely hear the cam lope - exhaust rap, etc. A plain ol double roller would have been a better choice. There is no reason for all that noise. I have heard quieter superchargers... :dunno:

AQK1
12-13-2004, 08:01 AM
I would install a crank trigger if your worried about more accurate ignition timing...

SDMAN
12-13-2004, 09:03 AM
Been running a Milodon gear drive in my Pontiac forever. No bearing issues, no valvetrain harmonics (dump the cheap factory balancer and get a good one) and dead quiet. You get what you pay for. The el cheapo dual idler gear drives are junk.

BADVELLE
12-13-2004, 10:19 AM
Been running a Milodon gear drive in my Pontiac forever. No bearing issues, no valvetrain harmonics (dump the cheap factory balancer and get a good one) and dead quiet. You get what you pay for. The el cheapo dual idler gear drives are junk.


I am the same, been running a Pete Jackson unit forever and a day, street/strip, daily driving, no issue to this point. I run a solid lift Crane unit, Harland Sharp rollers, etc., all looks as clean as the day I put them in. The engine is now out of the car, putting in a big-block, so I have had the chance to look at it. The fact with the noise, I don't even notice it anymore, the exhaust notes are much more prevelant. As for the Pontiac, if the gear drive is so loud (bloweresque) that you can't hear the cam coming through the exhaust, well I would say put in a bigger cam if that is the guys thing!

To each their own I guess, what ever floats your boat!