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roller cam bearings pros and cons

Discussion in 'The Hokey Ass Message Board' started by hemislave, Feb 9, 2011.

  1. hemislave
    Joined: Nov 14, 2010
    Posts: 23

    hemislave
    Member

    Hi all, Iknow this is probably not H.A.M.B. friendly so dont flog me to badly.:) I did do a search but didnt find any real information. The engine is a Chrysler 440 ,Indy heads ,roller cam, gear drive,roller rockers, 470 cu.in. cant go bigger on cu.in. pretty much at that combinations limit. We need more RPM, would roller cam bearings be worth the cost and hassel? I have been told it would probably pick up 3-400 rpm maybe? comments and opinions please Thanks.:D
     
  2. raengines
    Joined: Nov 6, 2010
    Posts: 227

    raengines
    Member
    from pa.

    info i have found claims the only benifit is from no oil falling on the crank from cam brg's. (the roller brg's get their oil from splash only) i have built several race engines with them with no problems and they are much easier to turn over by hand while setting valves , most use 50 mm size and need special ground cams. my race engines usually turn in the 8200/8400 area with normal brg's with anti friction coating.
     
  3. 73RR
    Joined: Jan 29, 2007
    Posts: 6,474

    73RR
    Member

  4. Hi!
    Joined: Oct 4, 2006
    Posts: 730

    Hi!
    Member
    from SoCal

    Your going to have to take the motor apart to do that and or change the cam. Expensive to do for what you get out of it and more for dry sumped engines anyways. Theirs more to it but not worth going into.
    Id say get a new custom cam ground.
    Your needs kinda dont make sence on somethings your saying. You can stroke the heck out of that motor.
     

  5. texoutsider
    Joined: Jul 6, 2005
    Posts: 826

    texoutsider
    Member
    from Frisco, Tx

    In our 427 FE Ford we have used the 460 bearings...just hog out the block and the cam od is the same. Works great. We do not oil up the heads, but do it like a Chebby, thru the pushrods..........

    M.
     
  6. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    CutawayAl
    Member
    from MI

    Roller cam bearings are a way of saving an expensive block that has spun a cam bearing, and people do run them on the street. But like most things automotive, there are pluses and minuses.

    To a point, plain bearings are more durable than roller bearings. The scales tip when valve spring pressures are so high that the plain bearings are failing. Under those conditions roller bearings will last longer than plain bearings. Or in other words, roller bearings tolerate overloading somewhat better than plain bearings, at least for a little while.

    Although some have EDMed a tiny oil hole in the outer race of roller cam bearings, they normally rely on splash for lubrication. Street engines spend part of their time at low RPMs and idling. Under those conditions oiling of the cam bearings is not adequate.

    I would start by quizing experts on your engine about how much spring pressure a 440 can tolerate without having bearing problems. If you need roller cam bearings then that is the end of the discussion. But all things considered, if you don't need roller cam bearings you are better off without them.

    As to gaining 300 to 400 RPMs, I don't know who told you that, but trust me, it's not going to happen. Most don't realize how low the frictional losses in a engine are. The pistons/cylinders account for most of that, followed by the cam/lifter. The drag created by the plain main, rod, and cam bearings is surprisingly low. If it wasn't the bearings would quickly melt. Think about this: Some motorcycles have plain bearings, others have roller bearings. The engines with roller bearings have no inherent power or RPM advantage over ones with plain bearings.

    One other thing, if you do end up using roller cam bearings, the cam's bearing journals need to be compatible with the bearings.
     
  7. hemislave
    Joined: Nov 14, 2010
    Posts: 23

    hemislave
    Member

    Thanks for the responses gentelmen, looks like we better look other places for more power.
     
  8. raengines
    Joined: Nov 6, 2010
    Posts: 227

    raengines
    Member
    from pa.

  9. greg32
    Joined: Jun 21, 2007
    Posts: 2,066

    greg32
    Member
    from Indiana

    Well said, we run 50mm and 55mm rollers in donovans. Spin them to 9200 regularly. They take the load of huge spring pressure better and have less friction. We run seat pressure of 400-450. Open pressure at lifts in the 1.1 inch range of 1000 lbs to 1200 lbs. Dont need them for the street, thats for sure. When assembling one of these and putting the rockers and push rods in, you cannot believe how difficult it is to turn the motor over by hand as the valve train gets loaded from the spring pressure.
     
  10. Lucky3
    Joined: Dec 9, 2009
    Posts: 652

    Lucky3
    Member

    X2...I also have hi rev race engines and only use roller cam brgs. These are primarily for improvement in parasite friction loss and the oil is not consumed on the cam brgs which helps valvetrain as well as crankshaft oiling quality. Pure race stuff and not sure how this would work on the street....
     
  11. hemislave
    Joined: Nov 14, 2010
    Posts: 23

    hemislave
    Member

    Thanks Greg32-lucky3 this is not a street engine it is a race only engine... similar to a drag engine runs 60-90 seconds at a time. and we have a cu. in., carb size limit, like I stated in my first post ,pretty much at the combanations limits. Trying to get more RPM out of it cause in our class wheel speed is important. (cant run higer final drive, dont have the power to turn it.:(
     
  12. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    CutawayAl
    Member
    from MI

    Because you posted on this forum I assumed we were talking about a hot rod street engine.
     
  13. Abomb
    Joined: Oct 14, 2006
    Posts: 1,659

    Abomb
    Member


    Truck / tractor pulling ?
     
  14. Hi!
    Joined: Oct 4, 2006
    Posts: 730

    Hi!
    Member
    from SoCal

    Are your heads and cam maxed out??
     
  15. Hi!
    Joined: Oct 4, 2006
    Posts: 730

    Hi!
    Member
    from SoCal

    Just to add. If this is a pulling vehicle. Wouldnt 400 RPM loaded equate to 100HP more needed or am I off here. I know on boats it can take that loaded.
     
  16. hemislave
    Joined: Nov 14, 2010
    Posts: 23

    hemislave
    Member

     
  17. Abomb
    Joined: Oct 14, 2006
    Posts: 1,659

    Abomb
    Member

     
  18. greg32
    Joined: Jun 21, 2007
    Posts: 2,066

    greg32
    Member
    from Indiana

     
  19. oj
    Joined: Jul 27, 2008
    Posts: 6,247

    oj
    Member

    Just to drive a nail in the roller bearing coffin, the O.D. of the bearings are a bit larger than stock cam bearings so you have to bore out a much larger hole in the block. Regular blocks are not designed for those bigger holes and weaken. The guys that do use roller cam bearings have blocks that are designed for them.
    Greg32, 1052hp with 528" is ferocious, somebody did you a good job!
     
  20. hemislave
    Joined: Nov 14, 2010
    Posts: 23

    hemislave
    Member

    Your uncles got a good looking ride Abomb. Greg32, cant spray it not allowed. we are thinking for next year building a new engine, Big bore shorter stroke. So lightning the rotating assy. is somthing to think about. getting things moving as quick as you can and keep the tires hooked is the name of the game. OJ its an Indy block I think there is enough there for bigger cam bearings.
     
  21. greg32
    Joined: Jun 21, 2007
    Posts: 2,066

    greg32
    Member
    from Indiana

    Thanks,we do our own motors, donovan bbc, winberg crank,aluminum rods, profiler 12 degree heads massaged heavily, single dominator on a cast intake, 15 to 1 static. We run a single stage fogger usually with a 44 or 46 pill. Thats about a 500hp shot. Having said that, I run a simple small block in my 32.
     

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