1968-75 Chrysler 318 boat engine

[Sled Puller]

Looking for a cheapy to get an old Penn Yann Tri- hull running.



Had a cracked block when we bought it. Boat isn't worth a brand new engine, just one that runs.



Anyone? Thanks,

Gene

 

[Joe G.]

Gene,



If the manifolds and heat exchanger (if it has one) are ok, then just get a 318 for a car and put the marine stuff on it.

 

[Sled Puller]

Manifolds are cracked also.

Thinking about taking the JB weld to it, got nothing to lose!

I would have to change the cam and heads on a car engine to get the same power. Then I would have to do the heads, etc, etc.

If I can get that runs without a complete teardown, I would be much happier!!



Gene

 

[Power Wagon]

Gene... What engine is this? Is it the "poly" engine, with the crossflow, nearly hemi heads, is this the industrial or marine version with the large thread injectors and odd looking intake, or is this the wedge engine?



Need to know those things, because your manifolds (water cooled, right?) and other accessories may not fit the wrong one.

 

[Sled Puller]

PW,

?



How am I supposed to know this stuff?? Its a boat engine!



From the boat people-" It is the same as the truck engines(68-75), 4bolt mains, better cam, big valves, etc.



The car engines of the time will bolt in, but run poorly, underpowered. . Newr stuff does not bolt in.



The intake looks basically stock, it is the exhaust that is goofy looking. 360's will work, but too much fuel burnage.





Gene

 

[Bad340fish]

The poly motors were dead in 66. Is it a reverse rotation motor? I know some marine motors turn the wrong way not sure which ones though. 318s are more then plentiful but I do not know about the marine ones. Also no SBM ever had 4-bolt mains.



I have never seen a Chrysler motor in a boat before. Seen some outboards but thats it. Sounds like you have a rare animal there.



JB weld MIGHT work on the manifolds since they run alot cooler than standard automotive manifolds.



A auto/truck 360 would work also(although the motor mount brackets are different) and maybe have the same fuel consumption of the "beefed" 318.



How bad is the crack and where is it at?? Maybe you could remove the engine and pin the crack?? Good luck!

Clark

 

[Sled Puller]

Now this is ironic.

A man who calls himself 340 FISH, does not know of Mopars in boats!!



Poly? Reverse rotation? This is getting to hard for me.





Reverse rotations are used in twin engine setups- yes you have to be careful when buying.



Lots of 360's and 440 Chrysler marine engines out there, but too much money, 2000 miles away, etc.



The entire water jacket on both sides of the block is rippled with cracks.



No 4 bolts? They seemed pretty sure it had 4 bolts. I'll check into that.

 

[Doc Tinker]

In the 70s and 80s the company I worked for bought a whole pile of marine 318s for me to use when I replaced engines in the Dodge vans that were used as airport limos. All the parts from the automotive engines fit the marine engines, so the marine stuff will work on the automotive engines. I'm not aware of a difference in power between the two engine versions.



I'd suggest that you start hunting for replacement manifolds, once you have them you should be able to find a junkyard 318 pretty cheap. I'll bet the manifolds will cost more than an engine.



Doc



EDIT: The limo company owned 50 vans in two different year models, 30 of one year and 20 of the other. It sure made life easy, once you got the hang of it, to whip engines and trannys out and throw in new ones. Me and a co-worker got to where we could syncronize our efforts and do jobs in a fraction of flat rate times. Sure was nice, when we could take extended lunch hours and feel justified in doing so.

 

[Power Wagon]

Originally posted by MGM

Now this is ironic.

A man who calls himself 340 FISH, does not know of Mopars in boats!!



Poly? Reverse rotation? This is getting to hard for me.





Reverse rotations are used in twin engine setups- yes you have to be careful when buying.



Lots of 360's and 440 Chrysler marine engines out there, but too much money, 2000 miles away, etc.



The entire water jacket on both sides of the block is rippled with cracks.



No 4 bolts? They seemed pretty sure it had 4 bolts. I'll check into that.

Gene... are the exhaust passages siamesed like late Mopars or are they evenly spaced? Are the plugs all at the same angle, or are they splayed between the cylinders?



Does it have short-reach plugs or long?



I have never seen or heard of a 4 bolt main 318. I can't imagine any need for it. It has a very beefy block, big bearings, and forged crank. And, marine or NOT, it's going to produce it's power at under 4000.



It's easy enough to ship a motor across country a ways. It doesn't cost that much.



But you telling me you have a marine motor doesn't mean much. It's much easier just to ask you to describe the parts so I can tell which engine it is. It's true the poly engines ended in passenger production in 1967, but that's not the only place they were used. Industrial engines were produced in poly form after that. And, what horsepower are you expecting? For most intents and purposes any 318 can easily make 200 HP with a cam change, 4 barrell, and open exhaust.



You don't want to swap in a 360, due to it being externally balanced. But for most intents and purposes, any 318 will work, and if you need more horsepower, just change cams and put in the right intake before you install it. The trick comes in getting one with the right style heads to fit your accessories.

 

[Bad340fish]

Hey MGM the fish in my name does not have anything to do with boats dude. Barracuda is more what it has to do with lol. For the Mopar Illiterate Barracuda is a car made by plymouth.



Poly is short for polyspherical(sp? wow) combustion chamber. Which is what all of the early(pre 67) 318s were. The poly motors are a little larger than the late 318 or LA motors. Any clue as to what that motor was rated at HP wise?? The automotive 318s were available with as much as 230 screaming ponys .



IMHO opinion if all it needs is a block i would find a 318 block with decent cylinders and have it honed out. Then toss all the stuff from the marine motor into that block. It would be easy and not cost you much at all. And you would know that it was fixed. Buying a used motor is kind of a shot in the dark. And I am sure its no picnic to R&R that motor.



The reason i mentioned the reverse rotation was a good one. A buddy of mine somehow ended up with a Marine 440 crank that was reverse rotation. Well no big deal except where the crank is grooved near the rear main seal to "pump" oil away from the seal was wrong. Resulting in a MAJOR oil leak as the marine crank pumped oil toward the seal when used in a standard rotation setup. Took many main seals and lots of hours to figure that one out.

DISCLAIMER I do not know jack about boats lol

Clark

 

[Sled Puller]

Yup, I knew it was for Barracuda, it was just funny in this situation!

The poly I knew nothing about.

Never know what you'll find out here,eh?



Gene

 

[Bad340fish]

lol Sorry MGM some people just do not get the whole fish and barracuda thing. My License Plate says FISHATK(Fish Attack) I have had people ask me questions ranging from "So you like to fish huh" and I explained it to a guy at a car show once and he still couldn't get it. I had to point to the little fish emblem on the back of the car lol.



Have fun with the boat, your right there is no telling what might be in there lol

Clark

 

[Doc Tinker]

BadFish said:

I had to point to the little fish emblem on the back of the car lol.

What's a Barracuda? I see those fish emblems on all kinds of cars. I never thought they meant there was a Barracuda in the tank



Doc