gear drives
 

overkill for a 600hp 540? if so what timing chain does everyone use?

Cloyes double roller will do the job just fine

Yea, But gear drives sound so cool!!!! I have them in a stroked 388 in my Toyota and in my big block 69 Chevy truck. might just have to put one in the 557 in the boat!!! Cool, So very cool!!

They sound cool but they are hard on the valvetrain.

What he said and costs you about 30hp on a small block. I'd rather go fast than break parts and sound cool. Cloyes all the way.

Rollmaster makes a nice timing chain set.

robs H/P...worthless if you not driving a cam driven fuel pump....

I agree. No reason to run them in a boat. Personally, I run a Jesel Belt.

Cloyes,true roller billet timing set..

interesting, they show no hp loss with a gear drive. what does it do to hurt valvetrain life?

There seems to be a lot of opinions on the topic, don't know how many people have actual proof of what they are posting. Best answer I read was, it all depends on application. Cummins puts gear drives in all of their motors, for what that's worth.

Cloyes or Comp billet double roller will handle just about anything thrown at it. If you want the noise of a blower,put a blower on it.

And I guess if its in car craft it has to be true...

It has to do with harmonics being trasferred from the crank to the valvetrain. While I dont have any testing data, I was under the understanding that gear drives transfer the most harmonics, chains come in second, while belts absorb all and transfer none to the valvetrain.

All today's diesels are gear drives but its not apples for apples. Have you seen the timing set in a diesel even a 4cylinder Isuzu? Big difference than what people are putting on their gas motors.

And years ago I did see with my own eyes a back to back dyno pull on a sbc it was 30 hp on a dyno.

I think all newer diesels run the injector pump off the front of the engine, I know several guys a while back dynoed race engines and showed loss of H/P on all, like Vinny said, belt transfer the least amount of harmonics back thru the engine...now Bob M. can probably give you the best info here...

International / ford don't run injector pumps and timing set is in the back of the motor. But it's not an apples for apples the harmonics in the two are different and diesels don't spin any kind of rpm. The timing sets in a diesel are totally different the gears are massive and the teeth on them are totally different compared to what is being put on a gas motor. If a gear drive was the answer I think General Motors would have put them on there motors a long time ago. And I'm sure GM put alot more money into R&D than Pete Jackson put into his gear drive. For that matter sine we are talking about boat motors why doesn't Mercury put them on there high dollar stuff?

I'm sure it's not cost effective for GM to use a $500 Milodon gear drive when a cheap chain and gear will do the job.

I don't think it's cost effective for anyone to pay $500 for a gear drive when a cheap chain drive will do.

I agree, but some of us run a bit more spring pressure and need them.

If your worried about the affects of spring pressure u might want to step up to a bigger cam core. Do you have any idea how far off the lobes on #8 are compared to #1 when the valves are adjusted?

Do you have any idea how far off the lobes on #8 are compared to #1 when the valves are adjusted?
No I don't.
I do know as I moved up in spring pressure, installing a new Cloyes chain and gears it wouldn't be long and the timing would be dancing all over the place. The Milodon cured that issue, I ran them for years without any problems. I run a solid roller, at fairly high RPM.
As far as the guy who started this thread, I don't think he needs a gear drive.

Spring pressure has absolutely nothing to do with needing a gear drive. You would surprised how little HP is needed to turn the valve train over once the motor is fired.

Dont forget driving the oil pump. Thats one of the advantages of running an external crank driven oil pump.. That way, as much load as possible is eliminated from twisting the cam core and retarding valve timing on the rear cylinders. Some race engines even run a front mount distributor driven off the belt drive.

Yes I know. And have you ever seen the belt for a front mount distributor? It's like a rubber band. Not much needed to turn a little plastic rotor. It does take some effort to turn the oil pump. But nothing like the forces of the valve springs. I cam can twist as much as 3 degrees from front to back... When I install a cam and use a chain I retard the cam a couple of degrees to compensate for chain stretch. They will advance when they stretch and they will stretch...

I didnt mean to imply that the distributor takes effort to turn, unless you are running a magneto. The advantage of running a front drive distributor, primarily for high rpm engines. is that the ignition timing wont retard as the cam twists.

And what are those front mount distributors mounted to? A belt drive timing set, not a gear drive. Hmmmmm...... :0)

Let us know what things look like when that Belt drive breaks at a hundred MPH. Jesel told me to expect 30 to 40 hours run time per belt in my application.

I wrench on a 865 nitrous motor with a Jesel Belt one of the times when it twisted the drive shaft 3 times and pulled out of the transmission the motor reved past 11000 rpm guess what the jesel belt jumped.., the motor still ran being off a tooth believe it or not. Didn't run that bad either. If you reved it up when it would come back down to an idle it would back fire. We spent an hour at the track b4 we figured out the belt jumped a tooth. A never would have thought it but sure enough did. Thank God the piston is .200 in the hole and no valves were bent. That's my Jesel Belt story. But never had any trouble with the little rubber band running the distributor. The main reason moving the distributor to the front is it will not fit on a motor like that. I don't see a problem retarding the timing when the rpm climbs cause we do it anyhow. When the nitrous starts the timing is 0. That's the only way a motor like that will live.