My boat project this winter has involved building a fresh engine for my Checkmate Convincor. I had a 454 Mag which I traded away and got a 502 EFI that needed some work. I have completely rebuilt it from the crank up including an upgraded cam recommended by Dean Nickerson. I am also adding a ProCharger with his consultation. I just discovered a potential hitch that I had not considered. My Bravo is a right hand rotation as indicated by a right hand prop turning clockwise when facing the front of the boat. My new engine is left hand rotation turning counterclockwise when facing forward. So, the questions are as follows:

1) Aren't cams ground opposite for left or right hand rotation? I didn't specify rotation when I bought this cam from Dean and now wonder if I have the wrong rotation cam.

2) What other items are different in the engine between left and right hand rotation?

3) Are blowers, specifically Pro Chargers, rotation dependant?

4) My Bravo would now rotate the opposite direction. This would require an opposite rotation prop, but I was going to change pitch anyway so no big deal. What other implication are there? Won't I now be using the upper gear for forward and is that arrangement inherently weaker?

This is a single installation so counterration is not a concern.

Any input would be greatly appreciated.

Thanx, Dave

The only Mercruiser engines that are
r/h rotation are some of the inboard/ v.drives.
All mercruiser stern drive engines are
l/h rotation.
Prop rotation in a bravo drive is
changed at the shifter mechanism
at the helm.
the bravo drive clutch mechanism
won't work on a r/h rotation engine,
due to the angle at which the clutch
shaft splines are cut.

An easy check would be to compare
firing orders between both engines,
if there both 1-8-4-3-6-5-7-2,
there both l/h rotation engines.
hope this helps.
jt

jt29olhp500s is correct. You probably have the wrong prop as dual engines usually have one drive rotate left, one right. You can run this prop by just changing the ratation at the helm. Just change the cable from one mount to the other.

Just for curiosity, what changes need to be make to make a rh rotation motor? I would assume cam grind and make some changes in the distributor......anything else??

Change engine to RH rotation:

Different cam.
Distributor gear (distributor still spins normal direction cause it drives the oil pump).
Water pump (reverse rotation pump).
Alternator fan blade.
(don't run a power steering pump on a RH motor).

In a performance application, the windage tray and crank scraper (if it has one) are different.

That's about it...

Mercruiser r/h rotation engines
run a timing gear setup, instead of
a chain, this lets the cam still
turn ccw, so oil pump still turns the
correct rotation.
Piston pin offset is reversed,
so notch faces rear of block,
instead of front.
The starter has to be set up
for r/h rotation.
jt.

I should probably clarify that
the gear drive set up is not the
set up you see with idler gears,
but crank gear directly drives the
cam gear.
jt.