Keeping in mind I think Roush may have had or has interests in the Hy-Vo, think I found a link a year or so ago.
Don't know if you can identify the gear drive, they only tested one, don't believe the brand was mentioned.
1996
Moderator: Team
Keeping in mind I think Roush may have had or has interests in the Hy-Vo, think I found a link a year or so ago.
That is a Pete Jackson or Pete Jackson knock off gear drive. That is not better than a chain. The fixed idler gear drives are far better, but I’ve never seen any testing of one of those verses a timing chain or belt. I’m going to test a Milodon fixed idler gear drive verses a timing chain next year. I’ll post the results.Tom68 wrote: ↑Sat Oct 01, 2022 7:29 amKeeping in mind I think Roush may have had or has interests in the Hy-Vo, think I found a link a year or so ago.
Don't know if you can identify the gear drive, they only tested one, don't believe the brand was mentioned.
1996
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So Iron headed Side Valves were made to last then ?Little Mouse wrote: ↑Sun Oct 02, 2022 2:41 pm You won't see an aluminum head or block, a chain, a needle bearing or stud rocker system on anything made to last.
Several years ago Hot Rod or Car Craft magazine did a belt drive, timing chain, gear drive comparison. They used a Jesel belt, Cloyes chain, and a Milodon gear drive. The gear drive won hands down. One thing they did find was the belt would retard cam timing as rpm increased, facilitating a need to advance the cam 2-4* to account for this. Higher spring pressures make this worse. Belts stretch, period...and that costs power. More and more serious engine builders, especially supercharged stuff are going with gear drives....Belts are still very prevalent but aren't being used nearly as much as they used to be. Belts only real advantage is being able to easily change cam timing and swap cams if needed. But, if you're having to adjust cam timing at the track to get better performance, you either didn't tune it properly on the dyno, or it's the wrong cam....ClassAct wrote: ↑Sun Oct 02, 2022 10:58 am That is a Pete Jackson or Pete Jackson knock off gear drive. That is not better than a chain. The fixed idler gear drives are far better, but I’ve never seen any testing of one of those verses a timing chain or belt. I’m going to test a Milodon fixed idler gear drive verses a timing chain next year. I’ll post the results.
I’m going to test it and post my results just because. I won’t have a belt drive unless someone wants to donate one for a SBM, but I’ll do a Milodon fixed idler against a chain.Coloradoracer wrote: ↑Sun Oct 02, 2022 3:42 pm I run a belt on my current setup, going back to a gear drive. There is a lot of bs out there about them. First off, Pete Jackson or similar gear drives are junk...pure junk.....secondly, the whole "gear drives transmit damaging harmonics to the valve train" is a bunch of bs as well. I've had the opportunity to talk to the engineers at Milodon and recently RCD about this....MYTH! Fixed idler, full cover style gear drives don't transmit anything more to a cam than a chain or belt.....if they were such an issue, the high end exotic cars wouldn't run gear trains.
Have you put 1 million 500 thousand miles on an engine and the gear drive system still good as new, the solid roller cam and its lifters like new, same crankshaft never been out of the engine same original head same block, have you ran 23 pounds to as much as 35 lbs a boost on aluminum for 1 million 500 thousand miles. I owned 15 class 8 engine' you don't see any crap like aluminum used, chains or needle bearing junk. What a junk air cooled engine have to do with anything. You want an air cooled engine for your daily driver pickup. Chains, belts don't last have to be replaced. If we just have to talk motorcycle engine a sportster since 57 till now has had 4 individual cams all gear driven and they were that way before 1957 in the kh flat head. 400 lbs seat 1100 open will wear out any chain or belt in no time.Tom68 wrote: ↑Sun Oct 02, 2022 3:19 pmSo Iron headed Side Valves were made to last then ?Little Mouse wrote: ↑Sun Oct 02, 2022 2:41 pm You won't see an aluminum head or block, a chain, a needle bearing or stud rocker system on anything made to last.
I have no idea what you're talking about. Not in this post or the one before.Little Mouse wrote: ↑Sun Oct 02, 2022 9:22 pmHave you put 1 million 500 thousand miles on an engine and the gear drive system still good as new, the solid roller cam and its lifters like new, same crankshaft never been out of the engine same original head same block, have you ran 23 pounds to as much as 35 lbs a boost on aluminum for 1 million 500 thousand miles. I owned 15 class 8 engine' you don't see any crap like aluminum used, chains or needle bearing junk. What a junk air cooled engine have to do with anything. You want an air cooled engine for your daily driver pickup. Chains, belts don't last have to be replaced. If we just have to talk motorcycle engine a sportster since 57 till now has had 4 individual cams all gear driven and they were that way before 1957 in the kh flat head. 400 lbs seat 1100 open will wear out any chain or belt in no time.Tom68 wrote: ↑Sun Oct 02, 2022 3:19 pmSo Iron headed Side Valves were made to last then ?Little Mouse wrote: ↑Sun Oct 02, 2022 2:41 pm You won't see an aluminum head or block, a chain, a needle bearing or stud rocker system on anything made to last.
Did that test ever happen? See my recent post on ST regarding HP loss on Gear Drive. Thanks.ClassAct wrote: ↑Sun Oct 02, 2022 5:28 pmI’m going to test it and post my results just because. I won’t have a belt drive unless someone wants to donate one for a SBM, but I’ll do a Milodon fixed idler against a chain.Coloradoracer wrote: ↑Sun Oct 02, 2022 3:42 pm I run a belt on my current setup, going back to a gear drive. There is a lot of bs out there about them. First off, Pete Jackson or similar gear drives are junk...pure junk.....secondly, the whole "gear drives transmit damaging harmonics to the valve train" is a bunch of bs as well. I've had the opportunity to talk to the engineers at Milodon and recently RCD about this....MYTH! Fixed idler, full cover style gear drives don't transmit anything more to a cam than a chain or belt.....if they were such an issue, the high end exotic cars wouldn't run gear trains.
Blame HP Books, S.A Design etc that everybody grew up on.
Every F1 and Indy Car engine in the last 45+ years has had a gear drive.