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Thread: Padding a 44 cube merc-

  1. #1
    Rumrunner
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    Default Padding a 44 cube merc-

    O gurus of phantom black?

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    Sam Cullis Mark75H's Avatar
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    You can do the porting yourself. Raise both sides .060" and square the tops of the ports. Make a scribe line with a piston ring as reference and stay on it.

    Boring and using oversize pistons will make no noticeable difference other than in your bank account.

    You can do the welding yourself ... it is done from the outside.

    One problem I see is that no one pads a 44 for 93 octane ... you are in experimental territory. I think the block you are starting with has a little pad in it that would have to be taken out to weld in something new, that will be exotic work.

    Since you have a lot of blocks to work with, you might consider mashing the heads instead.
    Since 1925, about 150 different racing outboards have been made.


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    - Skoontz's Avatar
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    Ok, got a question here....Since I know very little about Mercs except they have got dead end holes ( non removable cylinder heads ) have there have been higher tops made into the pistons in place of padding a cylinder? I know adding just a top will only raise the compression so much, where padding removes space from all the chamber.

    It seems like that would be the way to go rather than all the welding and such with padding.....
    Bill Schwab
    Dirty Deck Brewing
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    Team Member A/B Speedliner's Avatar
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    Default Cylinders

    Doug Kay has been sucessfull in maching off the low compression cylinder tops and welding on padded heads.
    David
    Old Race Boats Still Flip You Out

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    squishing the heads uggggg havent seen that for years since it seemed they all blew up when done ,,, at least around this neck of woods..

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    Default 4 Mercs

    1. You'd be FAR better off to find yourself a later, off-set plugs block and start from there. You can find blocks that used the same distributor, which makes your job easier. They have massive padding and more comp ratio to begin with, so you start with something easily as good as a padded, center plug 44. (Agreed, Sam?) My 67 vintage 44 is a great runner.

    2. PTs in America were NOT powered my "Merlins"--only a few British MGBs and MTBs got to use marinized Merlins. American PTs used Packard V-12s based on a water cooled version of the WW I Liberty V-12 (designed in a motel room by a few engineers in 4 days!)

    Jeff

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    Sam Cullis Mark75H's Avatar
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    Quote Originally Posted by Fastjeff57 View Post
    1. You'd be FAR better off to find yourself a later, off-set plugs block and start from there. You can find blocks that used the same distributor, which makes your job easier. They have massive padding and more comp ratio to begin with, so you start with something easily as good as a padded, center plug 44. (Agreed, Sam?) My 67 vintage 44 is a great runner.

    2. PTs in America were NOT powered my "Merlins"--only a few British MGBs and MTBs got to use marinized Merlins. American PTs used Packard V-12s based on a water cooled version of the WW I Liberty V-12 (designed in a motel room by a few engineers in 4 days!)

    Jeff
    Yes there is confusion about Packard building Merlin engines ... because they did build Merlins for other applications, most notably the P-51B and later variations of the Mustang. Packard was the only manufacturer ready to build more V-12's - Allison was already making as many as they could.

    http://www.ptboats.org/20-01-05-ptboat-008.html
    http://www.mustangsmustangs.com/p-51/p51specs.shtml

    The offset plug motors do have a different combustion chamber and pads ... BUT ... the compression is exactly the same ... 22 cc's

    I am sure Mr Kay's work is great, but I'm also sure its not in the price range that rumrunner is considering for a play motor.

    High compression pistons would work, but you have to order hundreds at once and you have to have a work ready die that can double the cost of production if you don't .... $2,500 or more ... for a few modified motors, its easier, faster and cheaper to modify the motor and run stock pistons.
    Since 1925, about 150 different racing outboards have been made.


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    That Tohatsu guy. jeff55vDSH's Avatar
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    How much H.P. do you hope to get from these mods? Without a set of open megaphones, I would guess maybe 5hp. And you'll lose a lot of bottom end power.
    If it were me, I'd try slipping a 65hp Merc under a 50hp cover or decals.
    But that's just me.
    Jeff Yungen

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    Sam Cullis Mark75H's Avatar
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    I agree the hp increase may only be 5 or 6 ... but I disagree that there will be any noticeable loss of bottom end at all ... unless you are trying to pull skiers or run a 2,000 pound boat
    Since 1925, about 150 different racing outboards have been made.


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    Default 44 Merc

    Just happen to have a 44 block that has has been padded and ported,along with the pistons for it. If you are interested let me know. Maybe we could work out a deal.
    Art Kampen

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