first decision...how the engine turns....

Discussion in 'Inboards' started by chriscraftbob, Nov 10, 2016.

  1. chriscraftbob
    Joined: Nov 2016
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    Location: Whiting, NJ

    chriscraftbob New Member

    First, I'm a newbie to the site, and wish to thank any who share their knowledge, insight, and advice. I'm on a mission, bought a great old project boat, 1978 Chris Craft Cutlass 22 Cuddy. She needs everything!!!! Engine is only useful as an anchor, so here is where I start: Right hand rotation small block Chevy. Two right hand rotation Paragon transmissions, one installed, one spare. My first decision, with lots of standard rotation engines available on the cheap, should I trade out the right hand transmissions for a standard left hand, and convert? Besides the trans, I'll need a starter (either way, really) and a prop, and what else to spin to the left? Next question: Is it possible to change the rotation (to the right) of a new long block, or are internal parts different? Thanks
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Why are you focused on the rotation direction ?
     
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    A typical SB Chevy is clockwise rotation (right) when viewed from the front. This is the standard and counter clockwise is used with the opposite side on dual engine installations and with other incidences. From a technical standpoint, all automotive/marine engines are viewed as if you're sitting at in the driver's seat, so the engine seems to be a counter clockwise thing, while looking at the flywheel. I mention this as Chris Craft did some weird stuff with their engines, including rotation, that aren't industry standard. The short of it is you have a standard rotation engine (CCR) while a right hand engine (reverse rotation) is the odd man out.

    To directly answer your questions, yes you can change out some parts for a clockwise engine You have a CCR engine), but why when you have the parts, for a standard rotation on hand? Yes, some internals will need to be changed, which are engine and boat manufacture (like Chris Craft) specific.
     
  4. Barry
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    Barry Senior Member

    Camshaft, alternator, distributor, probably oil pump, recirc pump on the engine
    Probably better to install a standard rotation engine and change out the trannys
     
  5. PAR
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    PAR Yacht Designer/Builder

    I'm assuming he has a standard rotation engine, just viewing it from the wrong end. Check the flywheel teeth. The side that's shinny, will be the contact side and a good indication of which way it turns (viewed from the flywheel end).

    As I mentioned, Chris Craft did some weird stuff with their reverse rotation engines, such as replacing the timing chain with gears, etc. It's probable the things he needs for a reverse rotation engine, he already has on the current engine. I don't see the need to do a full out drive swap, when all he needs is a long block and swapping out the reverse rotation stuff.
     
  6. Barry
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    Barry Senior Member

    I was under the impression, as well as you, that the standard rotation is left hand when viewed from the back. So he could very well have the standard rotation engine.

    If Chris craft replaced the chain drive with two gears then the cam shaft would turn in the opposite direction. If they replaced it with three gears then the cam would turn in the same direction as the crank and all parts should be a left hand standard rotation engine as viewed from the rear.

    The OP should look at the firing order which is usually cast into the intake manifold if it is 18436572, then the rotation is the standard rotation. Then a quick check under the timing cover, if there is a chain drive, everything is the same, if there are two gears the cam, distributor are turning in opposite directions, if three gears, the cam and crank are turning the same way

    Par do you know why Chriscraft swam against the stream with a different rotation

    I am not familiar with Paragon transmissions, I wonder which way they call their rotation, right hand from the input ie front which would then be left hand out of the engine mating to it
     
  7. Barry
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    Barry Senior Member

    """The Paragon trans can be set up for either rotation If its a hydraulic trans, the pump has to be changed to the correct position for the rotation. The pump is the same for both rotations but it has two possible locations that essentially flip the inlet and outlet ports to accomadate the rotation change.

    The reverse band also has to changed to its alternate position. That involves removing the gear set from the case.

    In forward, the Paragon uses a clutch in the gear set pack to lock the gear set up to give a direct drive 1:1 ratio. For reverse, the Paragon releases the clutch and applies a band around the gear set drum and the planetary gears in the set reverse the output shaft rotation and gives a 1.3:1 or so ratio change.""""

    the above from the chriscraft forum site, If you find that you have to change the direction of the tranny, this might be a fix, if it is true

    http://www.chris-craft.org/discussion/viewtopic.php?t=4423


    I think a very important point when discussing right and left hand rotation, the supplier should include the term "when viewed from the front or when viewed from the back of the engine
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The industry standard (marine/automotive) is the engine is viewed from the flywheel side.

    I too am a bit confused as to what he might have, though did make some assumptions. I think Chris Craft did the things they did to keep things proprietary and control part sales.

    Checking rotation is very easy and this is the first thing to look into.
     
  9. chriscraftbob
    Joined: Nov 2016
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    chriscraftbob New Member

    Thanks all, first would like to clarify "rotation". As I understand it, marine engine rotation is determined from behind the flywheel, looking forward(?). A standard rotating 350 would then be a left hand engine(?). My gearbox is a Paragon P21R, I believe R is for right hand rotation, so therefore have a counter rotation small block(?). I can buy a new 4bolt 350 long block (standard left hand) for under $1500, the best Reman deal I can find on a right hand engine is more than twice that. I will be paying for a gearbox rebuild either way, and was told the Paragon gearbox rotation can't be changed like a Velvet Drive(?). Figured I could swap out the two P21R's for a rebuildable left hand box, besides prop and starter(either way) what else would I need to run a standard rotation engine? Not sure what raw water pump I have. Trying to figure what makes best economic sense.
     
  10. mreoe4sure
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    mreoe4sure who me

    There is not a lot of differences between rt hand and left hand .GM motors as opposed to Fords. GM does not have an offset to their pistons for thrust like Ford, So the pistons do not care which direction the crank turns. The Crank is not different, but the rear main seal is ( Gray vs Black) on a two piece. The oil groves on the seal go opposite directions to guide the oil back to the pan. Ford on the old Commander 351 had the the grooves on the crank and a rope seals , so they use different Cranks depending in rotation . GM used a Gear to gear on Rt hand rotation motors so the cam turns the opposite direction as the Crank. So the distributor, oil pump are the same on Rt hand and left hand because the cams rotate the same direction and they are driven off the cam. I just converted a right hand to left hand for my own boat. So a 350 has different rear main seal, cam, cam drive, water pump, starter, alternator, and firing order that are rotation specific. So now you need to weigh the costs, is the cam in your junk motor good? Right hand rotation cams are expensive with the gear to gear setups. If your old is good you just need to swap the cam and gears and rear main seal and all your accessories .
     
  11. Barry
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    Barry Senior Member

    Not all right hand gm engines used a gear to turn the cam in the opposite rotation. If it did the left hand distributor would be fine
    Crusader right hand required a different distributor, as the rotation is different with the chain drive, the cam/dist gears put a thrust on the bottom of the distributor upper housing. So there is a thrust bearing installed to take care of this.
     

  12. Ike
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    Ike Senior Member

    Frankly, if you upgrade to a new fuel injected marine engine they are all standard rotation.
     
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