LM 318 Rebuild

Agitator · Post by **Agitator** » Thu Apr 17, 2008 3:41 pm

Guys, I'm rebuilding the 1971 LM318 in my Trojan F26. This is a reverse rotating engine. Are the standard rebuilding parts the same as an automotive engine ie: rings, rod and main bearings, oil pump, gaskets,etc?
Thanks

prowlersfish · Post by **prowlersfish** » Thu Apr 17, 2008 7:06 pm

Yes on most of the parts . But you do need to use marine head gaskits ( I would jut use a marine overhaul set )and becuse its is a revese rotaion you use a diffrent rear main seal and front seal.

Agitator · Post by **Agitator** » Fri Apr 18, 2008 7:43 am

Thanks Prowler,
I'm looking for a marine gasket set now.
Do you know what the difference is in a reverse engine? Is the cam different, firing order, distributor?
Thanks again

randyp · Post by **randyp** » Fri Apr 18, 2008 9:23 am

Are you talking about the rotation of the shaft?

Direct quote from my engine manual:

"Rotation: The rotation designation stamped on the engine serial number plate refers to the rotation of the propeller shaft when viewed from the stern looking towards the engine. The letter R indicates a right hand propeller shaft rotation; the letter L indicates a left hand propeller shaft rotation

Firing Order - Referring to the rotation and reduction designation on the engine Serial Number Plate:

For R10, R15, R20, R25, R30 and L19* Firing order 1-2-7-5-6-3-4-8
For L10, L15, L20, L25, L30 and R19* Firing order 1-8-4-3-6-5-7-2

(* The reasons for these exceptions L19 and R19 is that the design of the Warner 1,9:1 reductiong gear results in the propeller shaft turning in the opposite direction from the engine.)

For all V-8 engines the No. 1 cylinder is the front cylinder on the left side when viewed from the flywheel looking towards the water pump."

From the serial number reference - example LM318BWR10-678:

LM = model number
318 = cubic inch capacity
B = performance code
W = final drive
R = Propeller shaft rotation
10 = Final Drive Ratio (10 = 1.0:1, 15 = 1.5:1, etc.)
678 = Engine specification number

Hope some of this helps you out.

Agitator · Post by **Agitator** » Fri Apr 18, 2008 9:49 am

From what I understand, engine rotation is determined (CW or CCW) from looking at the fly wheel end of the engine. A reverse rotating engine turns CW while a standard/automotive engine turns CCW. I haven't torn mine apart yet nor have I done much research on the CW engine. I'll finish painting the hull this weekend and start the engine work next week. I'm curious to know what determines the rotation of the engine. How does the engine know which way to turn? What is the difference between a marine engine and an automotive engine? Just thinking out loud, I would assume the cam and distributor are different. Pistons? Do marine engines have a higher compression ratio?
Thanks...
The Agitator
A simple formula for avoiding confusion is to never let yourself get befuddled by an unclear understanding of what you're mixed up about.

randyp · Post by **randyp** » Fri Apr 18, 2008 12:02 pm

The Chryslers are automotive engine that have been "marinized" Same compression, etc as regular engines, but manifolds are designed to handle seawater and if yours is raw water cooled, like mine, there is no pressurized cooling system. The basics of the engine are the same - auto or marine. It's not the engine turning in reverse it's the crankshaft. Check out your engine tag and match it to the info I sent. You'll then know firing order, etc. There are good Chrysler shop manuals out there. I think Beacon may have them. If not. "GOOGLE" what you're looking for. Good luck!

prowlersfish · Post by **prowlersfish** » Fri Apr 18, 2008 5:34 pm

Randy if the crank is turning backwards the engine is runing backwards
( yes i know the cam and dist may turn normal due to a timing gears not a chain ( in some cases )

randyp · Post by **randyp** » Mon Apr 21, 2008 9:45 am

Oops! You're right. Just another one of my brain farts

Trojan Boat Forum

LM 318 Rebuild

LM 318 Rebuild

Thanks Prowler

Thanks Randy.