boot

Bigyellow, just wondering, what size motors are they ?

outer42

boot bring that boat to me,i'll get it going for you!!!!!!!!!!

formula31

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.

boot

NICE !! Thanks for the info !

TylerCrockett

iTrader: (1)

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

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

Dixie Doug

You can use a non-directional seal on both.Some seals have groves(yellow/blue,rear main) to keep the oil in the pan .

Cord

iTrader: (2)

If you reversed the oil pump, what would that do to it's flow?

BigSilverCat

you cannot reverse the oil pump it needs to still turn the same direction.

Cord

iTrader: (2)

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