nocigarette

should i be putting a milodon gear drive in my gen 6 572, that is what the engine builder is telling me he wants the timing to be precise.............or is he looking in the wrong direction

Panther

I hear the harmonics on a gear drive aren't too good....

If you want something good, get a Jesel belt drive.

Crazyhorse

Tell your engine builder "Jessel belt drive" if he wants precision.
If you want to stay with a chain you will want the Cloyes Tru-roller. Go to the website and check them out. Great product, great warranty

GPM

What is the lifespan of that belt, what do the valves and pistons look like when it breaks ?

BillK

nosig,

Personally, I have used a few gear drives at customers request, several Jesel belt drives on drag race engines, and a LOT of good old reliable Cloyes True Roller chain sets. I have never had any of them fail. I cannot speak to the "harmonic" issues with gear drives either.

That being said ... you have to be able to trust your engine builder. If he is going to stand behind his product, you really need to do what he wants to do. If he prefers gear drives, and has had good success with them, then let him do his part of the job the way he wants to do it. If you cannot trust his decisions, you probably should be using another builder, or doing it your self. I know this sounds harsh, but it is a fact of life.

Just my opinion,

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Reed Jensen

The problem with gear drives is they impart an opposing load on the cam and crank... Simple terms.... the crank and cam are pushed away from each other... A chain pulls the two together. The oil port on the camshaft is on the "bottom" where the load is for a chain. I've only heard anecdotal theories about "harmonics" being transmitted through the gears. I think Jesel belt drives are cool... They allow you to change timing without having to remove the damper and cover, but I wouldn't run one other than on a dyno for a short time to determine what cam timing works best for your application. Those belts are tiny compared to gilmer cogged drive belts on overhead cam engines. Even those belts have a short life and they're opening tiny valves by comparison. Go with a good roller chain. Early ford engines had gears... but only two... and one of them had a damper built into the gear to take out the harshness. The engines were designed to have the camshaft turn in the opposite direction of the crank and the gear faces were helical cut for less shock and noise.

nocigarette

Thanks guys, i trust the guy but i also like to due my own research.........The harmonic theroy i have heard before and undue stress on camshaft............I guess i will due what he says, he wont let me buy anything but the milidon gear drive and it is more exspensive than any chain and a little less than the jesel...............BACK UP AND PUNT I GUESS............

Panther

Not good when it breaks, I'll tell ya that first hand... My "old" builder insisted on putting in a certain manufacturers timing set and of course it didn't last. Half my valves were bent and the motor had to be completely rebuilt..

44MTI

I have run belt drives for the last couple of yrs with no problems.
I think some people are trying to over think the situation. There is reason merc swithed to the belt drive on their 900sc and continues to use them on the 1075.

bobkatz

Just my thought on the belt drive system, in a car or drag car, there is usually no oil, water or lack of air flow around the engine. On a boat there is little air flow around that area and usually water and oil floating around in there, plus the cost of replacement belts, around $90. The safe bet would be the well proven and reliable chain type. I also change from a jesel belt drive system to a chain type when i bought my boat.