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Reverse rotation engine question ...

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Old 08-16-2004, 01:11 PM
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Default Re: Reverse rotation engine question ...

Bigyellow, just wondering, what size motors are they ?
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Old 08-16-2004, 01:19 PM
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Default Re: Reverse rotation engine question ...

boot bring that boat to me,i'll get it going for you!!!!!!!!!!
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Old 08-16-2004, 01:32 PM
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Default Re: Reverse rotation engine question ...

Quote:
Originally Posted by boot
Hey Bigyellowcat, You didn't change anything in the bottom end ? What about the seals ?
How much time do you have on them now ? Thanks for your reply !
Ive got an open, reverse, short block in my shed. Ill look at the pistons and crank tonight to see if the pistons are reversed or if the crank oil holes are different.
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Old 08-17-2004, 10:53 PM
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Default Re: Reverse rotation engine question ...

NICE !! Thanks for the info !
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Old 08-18-2004, 10:18 AM
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Default Re: Reverse rotation engine question ...

one thing you need to do is polish the crankshaft in the direction of rotation because when polishing the crank it raises the metal and you do not want your oil flow going against the raised metal. Tyler
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Old 08-18-2004, 10:42 AM
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Default Re: Reverse rotation engine question ...

Merc and most marine builders reverse their crankshaft rotation but maintain normal cam rotation by using a gear rather than chain drive. That way you can use a standard distributor/oil pump setup. Cam is a different grind. The crankshaft p/n for merc is the same on left vs right rotation, so that doesnt seem to be an issue. Pistons and rods are also the same p/n. I've heard about reversing the pistons on older engines, not sure about that though. Only the rear seal is different, yellow instead of blue. Although there are people on this board using the wrong seal without problems. Front seal is the same.
That being said, Bigyellowcat pointed out you can reverse the rotation of both the crank and cam with a few modifications.
I hope formula31 can shed some light on piston direction.
Gary
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Old 08-18-2004, 10:49 AM
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Default Re: Reverse rotation engine question ...

Quote:
Originally Posted by Gary Anderson
Merc and most marine builders reverse their crankshaft rotation but maintain normal cam rotation by using a gear rather than chain drive. That way you can use a standard distributor/oil pump setup. Cam is a different grind. The crankshaft p/n for merc is the same on left vs right rotation, so that doesnt seem to be an issue. Pistons and rods are also the same p/n. I've heard about reversing the pistons on older engines, not sure about that though. Only the rear seal is different, yellow instead of blue. Although there are people on this board using the wrong seal without problems. Front seal is the same.
That being said, Bigyellowcat pointed out you can reverse the rotation of both the crank and cam with a few modifications.
I hope formula31 can shed some light on piston direction.
Gary
You can use a non-directional seal on both.Some seals have groves(yellow/blue,rear main) to keep the oil in the pan .
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Old 08-18-2004, 10:58 AM
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Default Re: Reverse rotation engine question ...

If you reversed the oil pump, what would that do to it's flow?
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Old 08-18-2004, 11:05 AM
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Default Re: Reverse rotation engine question ...

you cannot reverse the oil pump it needs to still turn the same direction.
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Old 08-18-2004, 11:52 AM
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Default Re: Reverse rotation engine question ...

I was wondering if that was why his buddy took out his crank bearings...
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