quote:

Originally posted by Alaskaracer:

quote:

Originally posted by Triple Nickel:
RCD gear drive is cats meow. It gives you the ability to degree cam in 1 degree increments. The Milodon is similar quality but only gives 2 degree adjustments. I've run both, they are both awesome. I'll never run a belt or chain on any race motors again. Same goes of ATI dampers....won't ever see one on any of my stuff ever again either.....

This is one NICE combo pictured.

What heads?
What cubic inch?
What induction?
Gas/alchol?

Thanks. No more belts for me ever again either. Admittedly, a belt saved my block when I broke a rod, but still won't run one again. Or aluminum rods for that matter.

I am curious why you say you would never use a belt again. A belt does a few key things besides extremely easy cam timing adjustments. A belt eliminates a huge amount of harmonics running through the valvetrain and it takes a hi load/wear component out of the internals of the engine.

quote:

it takes a hi load/wear component out of the internals of the engine.

Actually, it makes a high load/wear component easily replaceable each season....

quote:

Originally posted by Wildman:
I am curious why you say you would never use a belt again. A belt does a few key things besides extremely easy cam timing adjustments. A belt eliminates a huge amount of harmonics running through the valvetrain and it takes a hi load/wear component out of the internals of the engine.

Number one, if you're having to make cam timing adjustments at the track, you have the wrong cam....or it wasn't installed properly. I see no benefit to being able to do that other than something else that can go wrong, as in nuts not being tight enough on the cam gear and it coming loose, etc... Number two, I have yet to see ANY data about the whole harmonics thing.....and a full cover, single idler design gear drive does not transmit harmonics to the cam either...or the engineers at RCD and Milodon lied to me....which I seriously doubt. Number three, a belt is an unpredictable maintenance item that doesn't need to be that way. They stretch, Jesel recommends advancing the cam 2*, Comp 4* to allow for belt stretch, which gets worse with time......and high load/wear item? One less thing to worry about with my stuff. I've ran gear drives on virtually every engine I've ever done, until this last one. I ran a belt because at the time I put it together, there wasn't a raised cam gear drive that fit my block that I was aware of. So belt it was....Had to machine part of the damper hub off to get it to fit fully on the crank due to the width of the crank hub. I ran a Comp Cams drive, not sure if that has to be done with a Jesel or not. But, all being said, I've never believed or been a fan of the belt drive. I don't believe they are the best way to drive a cam, and it appears that more and more racers are going back to gear drives, especially in really high hp builds where Jesel used to be the norm....Yeah, still tons out there, and still tons being installed, but I think people are starting to trade varying cam timing, $200 belt replacements, and other possible issues for dead on cam timing and rock solid reliability. My cam timing is easy to change as well, but as I stated, if it needs to be changed at the track, something isn't right to begin with, and there is no advantage to being able to do that....

interesting

In 2011 I purchased a car with a 434 SBC, had Callies Magnum crank, new ATI damper and motor had 75 passes on it. I made about 75 passes and the crank snout broke off right behind the timing gear. Now I think it broke because the timing gear was not that good. I later found out it had done the same thing before I bought it.

I believe ATI is good and I think the Callies Magnum crank was good but when I went back I pulled the brand new ATI damper off of it and bought a new Fluidamper. Also went with a different brand crankshaft and a Jesel belt drive. Not going to take a chance on it happening again. Most of my motors now have Jesel belt drive except my 454 SBC has the CV Products Exceldyne belt drive.

Next motor I build will have the RCD gear drive. I just do not think they will stretch or wear like a belt does. Plus it has a much better mounting system than anything else out there if you run fuel pump or anything off the cam.

I agree with Mark, I am not going to be changing cam timing so that is not an issue.

Mark covers it pretty well. Similar experiences for me with Jesel belt drives. When they came out with the WHITE "rino" belt sometime in the late 2000 it was supposed to be for longevity and reliability, and better than the original black belt. My first one broke at around 100 runs or so and crashed the cylinder resulting in multiple exhaust valve pedestals having to be welded back onto the cylinder head. I broke a second white belt a year or so later and trashed the cylinder heads again. By that time Jesel abandoned the white belt and went back to the black belt. Also had trouble with the bolts/studs that are pressed into the upper sprocket turning when you torque the nuts after degreeing the cam. Imposible to fix without replacing the top sprocket.

Gear drives have none of these problems. They are not a wear item and cam timing is exact, precise, and never changes. The whole problem about harmonics I believe was targeted at the old dual idler dog bone gear drives taht didn't have a fixed idler and would fit under a factory timing cover. The RCD and Milodon gear drives are fixed idlers and have never been an issue for me.

I'd run a high end timing chain before I ran a belt drive and i don't like chains so for me its gear drive only if its a race motor.

quote:

Originally posted by Triple Nickel:
Mark covers it pretty well. Similar experiences for me with Jesel belt drives. When they came out with the WHITE "rino" belt sometime in the late 2000 it was supposed to be for longevity and reliability, and better than the original black belt. My first one broke at around 100 runs or so and crashed the cylinder resulting in multiple exhaust valve pedestals having to be welded back onto the cylinder head. I broke a second white belt a year or so later and trashed the cylinder heads again. By that time Jesel abandoned the white belt and went back to the black belt. Also had trouble with the bolts/studs that are pressed into the upper sprocket turning when you torque the nuts after degreeing the cam. Imposible to fix without replacing the top sprocket.

Gear drives have none of these problems. They are not a wear item and cam timing is exact, precise, and never changes. The whole problem about harmonics I believe was targeted at the old dual idler dog bone gear drives taht didn't have a fixed idler and would fit under a factory timing cover. The RCD and Milodon gear drives are fixed idlers and have never been an issue for me.

I'd run a high end timing chain before I ran a belt drive and i don't like chains so for me its gear drive only if its a race motor.

Yup. And just like running methanol, lots of misinformation out there.. Couldn't believe how much bias I found looking into all of this. I talked to one guy that said never again with a fluidampr...he said his engine guy couldn't get the crank in balance with it. I told him it says right in the literature to remove it from the hub, and only if the hub is counterweighted. He said it was a neutral balance, it was removed from the hub, and as soon as he replaced it with an ati, it was perfect. I told him bs...but insisted...yet wouldn't show the balance sheet....I actually called RCD and Milodon and talked to them....Learned a lot....I talked to Ivan at Fluidampr and he also put in in touch with one of the engineers there....what a learning experience.... There is another myth that NASCAR won't allow fluidamprs because they were breaking cranks....Yet after reading the rule book, its not there anywhere, and no one could provide even one shred of proof about it. Also, if you look on ATI's website they have that old graph of vibration testing, slamming fluidampr....yet admit even the test was rigged as it wasn't the correct damper for the test from fluidampr.....k


So that's only a fraction of what I've found....I honestly think at this point builders run that stuff not because it's the best for the application, but more due to them being able to make more money off the parts sales....Which I'm all about them making money, they need to...But I'm not going to run certain things anymore because "they are the best"....I want hard documented proof first....

Alsmost forgot to mention. If belt drives are so good, why are most manufacturers going back to chains where they previously ran belts? I know why....