2 standard rotation engines?

Engines, Shafts, Steering, Struts, Rudders, etc.
Leviathon
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2 standard rotation engines?

Postby Leviathon » Mon Nov 07, 2016 8:43 am

Can you use 2 standard rotation engines, and just change the rotation on one of the Velvet drives?? :?:
Steve and Mary Levi
1973 32' Marinette Fisherman
Twin Chrysler 360's
El Ohssa
St. Joseph, Michigan

EWRice
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Re: 2 standard rotation engines?

Postby EWRice » Mon Nov 07, 2016 11:21 am

No, and yes. When we talk about changing the direction of a velvet drive, it means matching it to the engine rotation. With one exception, the output of the transmission matches the input direction. Since you want your props to spin opposite directions (to counteract the rotational force of each other) you would have to have one trans that has an output that spins opposite of input in fwd. There is a reduction version that does this, but there is not a transmission with the same ratio that has input/output directions the same. You could find one with a close ratio and adjust your props, but that is alot of screwing around.

Plus, having two flywheels and rotating assemblies spinning the same direction, in an inboard boat, can have some strange gyroscope type effects. You don't get this in boats with I/O.
Muskegon Lake
1972 32' Express flybridge
Twin 318s
On board air & prime 920
1963 Thompson Super Sea Lancer
Graymarine 327
1961 Alumacraft 12'
'55 10hp Johnson

Leviathon
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Re: 2 standard rotation engines?

Postby Leviathon » Mon Nov 07, 2016 2:18 pm

Thanks - that is what I thought. Appreciate it!
Steve and Mary Levi
1973 32' Marinette Fisherman
Twin Chrysler 360's
El Ohssa
St. Joseph, Michigan

spdracer
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Re: 2 standard rotation engines?

Postby spdracer » Mon Nov 07, 2016 6:40 pm

You could if you switch to a ZF or Velvet Drive 5000 or Liberty series. Those transmissions use LH rotation inputs and can output LH or RH without an issue.
Chris Hamann
Lakeland Auto & Marine
Port Clinton, Ohio

EWRice
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Re: 2 standard rotation engines?

Postby EWRice » Mon Nov 07, 2016 8:19 pm

Does the ZF 1:1 have this ability? Or can you only do this with a reduction? I have never delt with either transmission (other than routine service). They must be good units.
Muskegon Lake
1972 32' Express flybridge
Twin 318s
On board air & prime 920
1963 Thompson Super Sea Lancer
Graymarine 327
1961 Alumacraft 12'
'55 10hp Johnson

spdracer
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Posts: 21
Joined: Fri Aug 05, 2016 6:59 pm
Location: Port Clinton, Ohio
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Re: 2 standard rotation engines?

Postby spdracer » Sun Nov 13, 2016 5:42 pm

The down angle transmissions are all reductions. ZF does make a copy for a velvet driver cast iron 1:1 in aluminum, but the same principles still apply.
Chris Hamann
Lakeland Auto & Marine
Port Clinton, Ohio