Propeller Rotation

[JohnDoe]

I've not witnessed a wake surf competition, but I would imagine that regaular surfers have the boat turn left in a circle. Couldn't "reverse" rotation mean that, goofy's go counterclockwise?

I suppose that might depend on your definition of 'left' and 'counterclockwise.' As opposed to my definition of this which is 'right' and 'clockwise.'

DOOOOHHHH!!! You're right Vin!...regular--driver turning left goofy--driver turning right

I'm glad you caught that before someone else did!

[Sixball]

CC has R H rotation to offset the drivers weight. I think it works. Bu is a littel weight sencitive and I don't see it in CC. Still love my Bu.

[SmoothWaterMan]

Lol....

Lots of good info here, and lots of speculation too.

Why CC started using reverse rotation engines I don't know, but as mentioned the common speculation was to counteract driver's weight. Personally that sounds to me like a marketing spin on buying Ford engines that were reverse rotation. If I was the PR guy I'd sure use it.

None-the-less, years later when production of these reverse rotation engines came to a stop, I'm sure CC didn't want to force their customers to learn to drive "the other way", so they simply swapped the gears in the tranny to use a standard rotation engine and still a RH prop.

And like the reverse rotation engines before them, when Ford stopped building 351's CC/PCM paid them to stockpile a warehouse or two for them to use, and then reluctantly switched over to GM blocks. Ford 351 production was actually done a year or two before PCM was providing only GM blocks to CC.

While Malibu's/MC/Skiers Choice/etc/etc/etc all use LH props, an easy way to tell is this. Put a prop in the open palm of your hand. In one hand your hand will naturally fit the hub and your thumb will lay nicely up a blade. The same prop in the other hand your thumb can not - it will run into the blade, and is hard to hold in the same manner. The hand the prop fits is the rotation. (provided you know your left and right hands)

Peter

[vette-ski]

Put a prop in the open palm of your hand. In one hand your hand will naturally fit the hub and your thumb will lay nicely up a blade. The same prop in the other hand your thumb can not - it will run into the blade, and is hard to hold in the same manner. The hand the prop fits is the rotation. (provided you know your left and right hands)

Or just look for the "L" or "R" stamped on the hub.

OK, I don't have experience with other prop brands like some of you do so maybe they all don't, but the acme props are marked.

[Sixball]

Lol....

Lots of good info here, and lots of speculation too.

Why CC started using reverse rotation engines I don't know, but as mentioned the common speculation was to counteract driver's weight. Personally that sounds to me like a marketing spin on buying Ford engines that were reverse rotation. If I was the PR guy I'd sure use it.

None-the-less, years later when production of these reverse rotation engines came to a stop, I'm sure CC didn't want to force their customers to learn to drive "the other way", so they simply swapped the gears in the tranny to use a standard rotation engine and still a RH prop.

And like the reverse rotation engines before them, when Ford stopped building 351's CC/PCM paid them to stockpile a warehouse or two for them to use, and then reluctantly switched over to GM blocks. Ford 351 production was actually done a year or two before PCM was providing only GM blocks to CC.

While Malibu's/MC/Skiers Choice/etc/etc/etc all use LH props, an easy way to tell is this. Put a prop in the open palm of your hand. In one hand your hand will naturally fit the hub and your thumb will lay nicely up a blade. The same prop in the other hand your thumb can not - it will run into the blade, and is hard to hold in the same manner. The hand the prop fits is the rotation. (provided you know your left and right hands)

Peter

Ford built reverse rotation for the marine industry. the autos weren't and I thought the 351 CC used was the windsor not the cleveland.

[Green_Giant]

Lol....

Lots of good info here, and lots of speculation too.

Why CC started using reverse rotation engines I don't know, but as mentioned the common speculation was to counteract driver's weight. Personally that sounds to me like a marketing spin on buying Ford engines that were reverse rotation. If I was the PR guy I'd sure use it.

None-the-less, years later when production of these reverse rotation engines came to a stop, I'm sure CC didn't want to force their customers to learn to drive "the other way", so they simply swapped the gears in the tranny to use a standard rotation engine and still a RH prop.

And like the reverse rotation engines before them, when Ford stopped building 351's CC/PCM paid them to stockpile a warehouse or two for them to use, and then reluctantly switched over to GM blocks. Ford 351 production was actually done a year or two before PCM was providing only GM blocks to CC.

While Malibu's/MC/Skiers Choice/etc/etc/etc all use LH props, an easy way to tell is this. Put a prop in the open palm of your hand. In one hand your hand will naturally fit the hub and your thumb will lay nicely up a blade. The same prop in the other hand your thumb can not - it will run into the blade, and is hard to hold in the same manner. The hand the prop fits is the rotation. (provided you know your left and right hands)

Peter

Ford built reverse rotation for the marine industry. the autos weren't and I thought the 351 CC used was the windsor not the cleveland.

mine was for sure a windsor

[TRBenj]

That make sense. So was the 1.23 tranny invented to save money on engines and still be able to use RH props, or is the reduction tranny spinning a bigger prop at a slower speed a good idea. I've never driven one.

From what I can tell, the PCM 1.23 was designed with 3 nice features in mind:

1) Reduction drive. By turning a bigger prop at a slower speed, holeshot is improved. Top end is nearly identical when comparing boats with the same hull and motor, 1.23 vs. 1:1 trannies. My '90 with 240 hp got an instant 3,000 RPM out of the hole, which is a few hundred more RPM than the 1:1 boats Ive been in- so youre further into the powerband right off the bat.

2) Reversion of the drive direction. This allowed CC to make the switch to standard rotation motors while still turning their signature RH prop. The driving factor might have been cost, but it sure makes it easier to find parts (cams, rear main seals, distributor gears, etc) now when rebuilding or doing motor work.

3) Incorporation of down angle. I believe the tranny redirects the drivetrain somewhere around 7-10 degrees. This allows the motor to sit much more level in the boat, which allows the use of a shorter motorbox and improves the circulation of fluids in the motor.

I know some guys have actually switched their CC single exhaust back to duals with Malibu tips and all.

I actually only know of one person who has done this... me The tips are similar in style, but are not Malibu units. Theyre actually 4" in diameter with internal flappers. You can see them for yourself in ME next month.

Im not sure when CC started using reverse rotation motors, but it was a long time ago (early 60's or earlier). I believe Chris Craft, Century and many other manufacturers used them back then as well. On bigger inboards with dual motors, I think it was common to have the 2 props turning in opposite directions- so reverse rotation motors werent just CC oddballs.

As far as I know, CC never installed any Cleveland motors- though Ive heard there were some Donzi's had them. All the small block Fords that went into CC's were Windsors.

[vette-ski]

Pretty sure the Cleveland is a big block.

[88Skier]

That make sense. So was the 1.23 tranny invented to save money on engines and still be able to use RH props, or is the reduction tranny spinning a bigger prop at a slower speed a good idea. I've never driven one.

From what I can tell, the PCM 1.23 was designed with 3 nice features in mind:

1) Reduction drive. By turning a bigger prop at a slower speed, holeshot is improved. Top end is nearly identical when comparing boats with the same hull and motor, 1.23 vs. 1:1 trannies. My '90 with 240 hp got an instant 3,000 RPM out of the hole, which is a few hundred more RPM than the 1:1 boats Ive been in- so youre further into the powerband right off the bat.

2) Reversion of the drive direction. This allowed CC to make the switch to standard rotation motors while still turning their signature RH prop. The driving factor might have been cost, but it sure makes it easier to find parts (cams, rear main seals, distributor gears, etc) now when rebuilding or doing motor work.

3) Incorporation of down angle. I believe the tranny redirects the drivetrain somewhere around 7-10 degrees. This allows the motor to sit much more level in the boat, which allows the use of a shorter motorbox and improves the circulation of fluids in the motor.

I know some guys have actually switched their CC single exhaust back to duals with Malibu tips and all.

I actually only know of one person who has done this... me The tips are similar in style, but are not Malibu units. Theyre actually 4" in diameter with internal flappers. You can see them for yourself in ME next month.Im not sure when CC started using reverse rotation motors, but it was a long time ago (early 60's or earlier). I believe Chris Craft, Century and many other manufacturers used them back then as well. On bigger inboards with dual motors, I think it was common to have the 2 props turning in opposite directions- so reverse rotation motors werent just CC oddballs.

As far as I know, CC never installed any Cleveland motors- though Ive heard there were some Donzi's had them. All the small block Fords that went into CC's were Windsors.

I plan to, High Techs and all.

I haven't heard a theory about reverse rotation that I've totally bought, yet. All I know is until 1992, when we got our 88 Skier, which has a LH PCM 240 Ford, I had only seen RH inboards. I wonder if the old I/Os are reverse rotation?

[TRBenj]

Pretty sure the Cleveland is a big block.

You could be right. Im not very familiar with the Cleveland, but I do know some parts interchange with the 460 BB.

Bruce, I couldnt tell you about the I/O's... my knowledge is limited to inboard ski boats (CC's in particular). See you in a few weeks!

[88Skier]

Pretty sure the Cleveland is a big block.

The Cleveland was a 351, they could have been big blocks also, but they were definately a 351, too. They were supposed to be a faster motor than the Windsor. I always heard one way to tell the difference is the angle the spark plugs installed. IIRC they stopped making them around 1970.

[Sixball]

Clevland is not considered a big block It has Canted valves and also larger valves. I don't think all but the good ones had four bolt mains. We used them in our drag car. Carburated on gas in mid 70's we could get 850 to 900 H.P. That was in a de-stroked 351 down to 334. Nothing stock but thay were good motors. Still have one.

[JasonK]

Doesn't the motor, not the trans, dictate the rotation?

I think my 1990 has RH rotation, not sure though.

[SunriseH2OSkier]

Put a prop in the open palm of your hand. In one hand your hand will naturally fit the hub and your thumb will lay nicely up a blade. The same prop in the other hand your thumb can not - it will run into the blade, and is hard to hold in the same manner. The hand the prop fits is the rotation. (provided you know your left and right hands)

Or just look for the "L" or "R" stamped on the hub.

OK, I don't have experience with other prop brands like some of you do so maybe they all don't, but the acme props are marked.

[uk_exile]

CC has R H rotation to offset the drivers weight. I think it works. Bu is a littel weight sencitive and I don't see it in CC. Still love my Bu.

I think the CC's less weight sensitivity is more from their soapdish fatboy hull shape than the different prop rotation

[TRBenj]

CC has R H rotation to offset the drivers weight. I think it works. Bu is a littel weight sencitive and I don't see it in CC. Still love my Bu.

I think the CC's less weight sensitivity is more from their soapdish fatboy hull shape than the different prop rotation

The current 196 is actually fairly sensitive to weight- more so than my '90. Im sure the RH prop helps some- you can feel the boat level out if you nail the throttle at speed.

Doesn't the motor, not the trans, dictate the rotation?

I think my 1990 has RH rotation, not sure though.

Not necessarily. Like I mentioned above, CC has used both LH and RH motors to turn their signature RH prop. The current 1.23 tranny reverses the engine rotation, so they currently use all standard rotation motors. Admittedly, Im not that familiar with Malibus- but I think theyve always used LH (standard rotation) motors and LH props with 1:1 tranny's.

[88Skier]

All of the Malibus that I have seen are left handed. In the 1980's there was great growth of ski boat manufacturers. Prior to that, there had only been Correct Craft and Master Craft, and they were right handed, as had all the old inboards that had gone out of business, Chris Crafts, Owens, Dunphy, etc. All of this new competition was good for the industry and boats, like cars, improved greatly from the stuff that was turned out in the 1970's. They progressed from RH props to LH props. For some reason, CC has stayed with their RH props, (not that there's anything wrong with that).