Marine Hemi Rotation

Discussion of the Marine / Industrial Hemis.

Moderators: TrWaters, 392heminut, scottm

Post Reply
Posts: 10
Joined: Thu Nov 25, 2004 6:00 pm
Location: Honeoye Falls NY

Marine Hemi Rotation

Post by XXLCH » Fri Nov 26, 2004 6:51 am

Revised 12-2

The "right" engine, looking at distributor end, rotates CCW.
The Chrysler Maintenance Manual, page 157, for a M45 S Marine Engine shows Fig. 37--Firing Order (Right Hand Rotation) 1-5-6-3-4-2-7-8.

Left engine rotates CW looking at distributor end.

Checked engines pulled from a twin engine Hemi powered cruiser.
Marine Engine Model plates, located below distributor, at front of engine (non-transmission end), read:

M 45 S HR 3210 R
M 45 S HL 3209 R

The R in HR, and the L in HL designate these as right and left engines, according to a Marine Engine Model plate picture shown at

Mounted in the center of the flywheel/ring gear is a small tube with a slot to take a tool with a dog to hand-crank the engine. I made up a soft steel tool (large bolt with hole drilled to take a short rod) to engage the slot to turn the engines. The slot is designed so that if the engine starts, it throws out the tool used to crank it.

Sure enough, I had to crank the engines in different directions. My limited experience is that "Left" engines are considered "normal", and "right" engines, when so designated, are opposite rotation. The fact that right engines are typically more expensive than left engines of the same type also may indicate this is a legitimate claim (seen in adds in boating mags). Single engined boats typically get "left" engines.

However, according to Bailiesdad, the right engine is the normal engine. He's got a hemi powered boat so he'd know for sure.
Looking at what woud be the front of a car engine you'd see CW rotation of the marine engine (CCW at flywheel end).
Just read in a book on old hemi's that some boats hooked flywheel end to tranny as well.

The distributor end of the engine faces front in the marine application I looked at. The transmission is bolted to the non-distributor end of engine. The "right" engine, looking at distributor end, rotates CCW.
Last edited by XXLCH on Thu Dec 02, 2004 5:39 pm, edited 6 times in total.

Posts: 433
Joined: Sat Dec 01, 2001 6:00 pm
Location: Maryland

Post by Bailiesdad » Fri Nov 26, 2004 7:28 pm

In Chrysler Marine engines the RH engine is same as car, LH is reverse.

Post Reply