Gear Drives
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 14 of 20

Thread:
Gear Drives

  1. #1
    Sit N' Spin Jetaholic's Avatar
    Join Date
    Dec 2007
    Location
    Droppin' the kids off at the pool
    Posts
    1,423

    Default Gear Drives

    Good? Bad? Pros? Cons?

    Which is the most durable for a jet boat engine, fixed or floating idler setup?

    Even better, how about ordering a reverse rotating cam and run the non-floating type setup (the kind where the cam and crank gears are direct coupled)?

    Are the "quiet" gear drive sets actually quiet?



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    steelcomp was here
    Join Date
    Dec 2007
    Location
    n/e TN
    Posts
    26,507

    Default

    Just run a good chain and you'll be fine.
    Last edited by scott foxwell; 12-27-2008 at 08:48 PM.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

  4. #3
    Senior Member Factory1's Avatar
    Join Date
    Oct 2008
    Posts
    1,134

    Default

    Gear drives are good at transmitting destructive harmonics from the bottom end to the valvetrain, and breaking things. I think there is more reasons not to use them than there are to use them. I'm sure there are some people that swear by them though. I ran a cheap dual idler setup on my last flat, and upon one teardown I found small broken pieces of the flat wound damper springs in the oil pan. I wouldn't use one again. I'm with Steel, chains are under estimated because they are so common, and non blingy, but they work, plain and simple. Rollmaster makes some pretty nice looking stuff. If you really want to get fancy, buy a belt drive. They don't transmit harmonics at all, and cam timing changes can be made in minutes.
    Last edited by Factory1; 12-28-2008 at 09:21 AM.

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Member imbill's Avatar
    Join Date
    Jan 2008
    Posts
    60

    Default

    a good ol double roller or a belt !!!!!!!!!!!!!

  7. #5
    Senior Member
    Join Date
    Dec 2008
    Location
    Sacramento area
    Posts
    1,136

    Default

    I saw an article in performance engines. They made dyno pull with the same engine just changed the timming drive system. They all made almost the same HP but the chain made the most. It was only by 1hp. The range between all of them was only 2 or 3 ponys. I was surprised. I thought the belt was supposed to be the moat productive.

  8. #6
    Cantard 71hallett's Avatar
    Join Date
    Mar 2008
    Location
    snow bank
    Posts
    5,017

    Default



    One of these?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	how not to build a bbc 012.jpg 
Views:	393 
Size:	89.2 KB 
ID:	28181  
    Quote Originally Posted by gn7 View Post
    It would be a balmy 85* in Steel's shop if he would move a little faster

  9. #7
    Senior Member ol guy's Avatar
    Join Date
    Mar 2008
    Location
    Lake Elsinore Ca
    Posts
    3,855

    Default

    Quote Originally Posted by Factory1 View Post
    Gear drives are good at transmitting destructive harmonics from the bottom end to the valvetrain, and breaking things. I think there is more reasons not to use them than there are to use them. I'm sure there are some people that swear by them though. I ran a cheap dual idler setup on my last flat, and upon one teardown I found small broken pieces of the flat wound damper springs in the oil pan. I wouldn't use one again. Those GOD chains Steel talked about sound pretty heavenly, wouldn't mind getting my hands on one of those! Just kidding Steel, I just couldn't resist with our past and all! I'm with Steel, chains are under estimated because they are so common, and non blingy, but they work, plain and simple. Rollmaster makes some pretty nice looking stuff. If you really want to get fancy, buy a belt drive. They don't transmit harmonics at all, and cam timing changes can be made in minutes.
    Ditto on that!!! And I will not go into the god chain thing, I'm a walking disaster when it comes to a key board so I leave that at that. I have ran gear drives and still to this day believe that a good double roller will do just fine in a jet-boat!!!! R.P.M. have alot to due with the reason to run a gear drive. I will add that they sound great but cost on the big end! If Chevrolet didn"t believe in them, the bolt holes in the cam gear riding area would not be there? Can Am back in the old days when the chevy guys were turning a 427 over 9k maybe?????M

  10. #8
    Cantard 71hallett's Avatar
    Join Date
    Mar 2008
    Location
    snow bank
    Posts
    5,017

    Default

    I know a couple guys backing away from the belts...."hey that looks cool...I want one" to "well it didnt nip parts before" A little in the chain can also be a good thing. But I guess the word chain just sounds old and boring.
    Quote Originally Posted by gn7 View Post
    It would be a balmy 85* in Steel's shop if he would move a little faster

  11. #9
    Senior Member ol guy's Avatar
    Join Date
    Mar 2008
    Location
    Lake Elsinore Ca
    Posts
    3,855

    Default

    Quote Originally Posted by 71hallett View Post
    I know a couple guys backing away from the belts...."hey that looks cool...I want one" to "well it didnt nip parts before" A little in the chain can also be a good thing. But I guess the word chain just sounds old and boring.
    So I will bight! what do you think the cause of that would be? I will toss my balls in the fire and say that extreme spring pressure along with the big cam theory of today will eat up a Jessel Belt Drive??? RSVP I would like your'e idea on thisMark

  12. #10
    Lurker
    Join Date
    Dec 2007
    Location
    NC
    Posts
    1,417

    Default

    If I had the money, a belt drive is all I would run.
    They are by far the best at reducing harmonics being transmitted from the crank into the valve train while still maintaining cam timing precision.
    The Nascar guys with their mandated flat tappet cams were the first to over power the old belt system.
    When we started having failures we realized that the industry standard 25mm belt as designed was only good for about 28hp of force. Along came the 30mm stuff we have today. The bigger belts, along with advances in belt material and construction have made this a non-issue again, and can more than handle the loads presented by today's flat tappet cam/flooded valve train, or the most aggressive roller cams and high spring pressures. As long as they don't get over heated, things are good again.
    This comes from Witnessing this failure/transition period first hand, and being part of the development of today's modern systems.
    Will this development/progression stop here? Of course not, but for now I believe things are under control again......for now anyway!

    As always, just MHO!

  13. #11
    steelcomp was here
    Join Date
    Dec 2007
    Location
    n/e TN
    Posts
    26,507

    Default

    Ditto what Warp says...the new belts have eliminated the problems the older belts were having. I'm going with a belt on my next engine, even if I have to wait to be able to afford it. Cam timing access is another plus on belt drives. Really helps cut down on time on the dyno.
    For a chain, the Rollmaster seems to be what everyone is using. I used them on the last two builds and found nothing I didn't like about them. The first was with the Rolon chain, which everyone said to be careful with, but it just finished it's third season, and this blower engine I just did has the Iwis chain. It's supposed to be the hot ticket. Frankly, the best double roller I ever bought was an el-cheapo from PAW (their "premium" roller) with a USA made chain (I'm guessing it's a DID, but all it says is made in USA) that lasted forever, and I still have it on the shelf. The chain out of the 900hp Duttweiler496 BB Ford that I took out of my boat has an English made Reynold chain and it was still plenty tight. There are some nice ones out there.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

  14. #12
    Senior Member VDRIVERACING's Avatar
    Join Date
    Jan 2008
    Location
    Atlantic Beach, FL
    Posts
    1,640

    Default

    Quote Originally Posted by Warp Speed View Post
    If I had the money, a belt drive is all I would run.
    They are by far the best at reducing harmonics being transmitted from the crank into the valve train while still maintaining cam timing precision.
    The Nascar guys with their mandated flat tappet cams were the first to over power the old belt system.
    When we started having failures we realized that the industry standard 25mm belt as designed was only good for about 28hp of force. Along came the 30mm stuff we have today. The bigger belts, along with advances in belt material and construction have made this a non-issue again, and can more than handle the loads presented by today's flat tappet cam/flooded valve train, or the most aggressive roller cams and high spring pressures. As long as they don't get over heated, things are good again.
    This comes from Witnessing this failure/transition period first hand, and being part of the development of today's modern systems.
    Will this development/progression stop here? Of course not, but for now I believe things are under control again......for now anyway!

    As always, just MHO!
    Warp - Do you know who makes the 30mm for BBC? Only one I found was Herbert...

  15. #13
    Lurker
    Join Date
    Dec 2007
    Location
    NC
    Posts
    1,417

    Default

    Quote Originally Posted by VDRIVERACING View Post
    Warp - Do you know who makes the 30mm for BBC? Only one I found was Herbert...
    Did you check CV products?

    They show one for a BBC with a std cam location, but don't give any other info.
    Their web-site has always sucked but it appears they are in the middle of fixing that, but don't have it finished.
    I would contact them. It is a nice piece!

  16. #14
    Senior Member
    Join Date
    Dec 2007
    Location
    Newbury Park, Ca/Mohave Valley, Az
    Posts
    8,169

    Default Huh? what you say, eh, speak up sonny.....

    Quote Originally Posted by Jetaholic View Post
    Good? Bad? Pros? Cons?

    Which is the most durable for a jet boat engine, fixed or floating idler setup?

    Even better, how about ordering a reverse rotating cam and run the non-floating type setup (the kind where the cam and crank gears are direct coupled)?

    Are the "quiet" gear drive sets actually quiet?
    Quieter than a cannon going off in your kitchen, but thats about it.

    My previous comment was directed at the Milodon type gear drive with the idler gear in the timing cover. I like these because you can adjust the timing in 2* increments by just rotating the upper gear on the cam hub. I say Milodon, but several others also make this style timing cover with the removable front plate. Also the front plate can be a fuel or water pump drive type....As Steel has said, "a decent chain and you'll be fine"..........
    LOUD BOATS SAVE LIVES

+ Reply to Thread
Page 1 of 2 1 2 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in

Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95