Marine 360

[TK]

So, I am looking, and probably buying a 70 Uniflite, with a 360 marine engine. It runs excellent. So, the first thing I noticed, is the little AFB sitting on top of a single plane manifold, looks exactly like the little single plane 2bbl manifold, with a 4bbl hole. Kinda neat, I thought, makes sense, a marine engine does not need hardly any low end torque.

Then, on further inspection, I popped the oil cap off, and inside, was iron adjustable rockers, not the roundish looking stock type 273 rockers, but an aftermarket looking set, and the springs looked huge, and the valves looked taller.

I am having a hard time finding specs on this engine, did they come built different? I was fully expecting a stamped style valvetrain......... It also sounds like the cam is gear driven.

Any idea's? You guys worked on these before? The block is a 73.

[Dick]

Marine engines are built with exclusive features like sealed distributors, starters, alternators/generators. There can be no open spark anywhere. The carburetors must be drip proof. and fitted with a BFA. The fuel pumps must have a closed circuit weep hole. Inboards are usually reverse rotation and cammed and cranked accordingly. The gaskets are of better quality to resist corrosion. Water pumps usually have stainless backplates.

As a result of these differences, repair parts are considerably higher in price, because marine spec is a license to steal.

[TK]

It is not counter rotating, I checked that. I was looking for the internal difference. Or, is this a custom built motor? In the auto world, a 360 never had adjustable valvetrain.

And man does it sound strong................. Sounds like a built auto motor.

[nhdriver]

Originally Posted by Dick

Marine engines are built with exclusive features like sealed distributors, starters, alternators/generators. There can be no open spark anywhere. The carburetors must be drip proof. and fitted with a BFA. The fuel pumps must have a closed circuit weep hole. Inboards are usually reverse rotation and cammed and cranked accordingly. The gaskets are of better quality to resist corrosion. Water pumps usually have stainless backplates.

As a result of these differences, repair parts are considerably higher in price, because marine spec is a license to steal.

You are right about the H.D. components, but reverse rotation is only used on one engine in a dual engine installation, so the props don't "steer" the boat on hard acceleration. Single engine installations usually have the standard rotation. Reverse rotation engines were much more expensive to produce.

[dodger1]

Single-plane low-rise 4-bbl sounds like a 273 piece, but the heads?? And what's wrong with the Bayliner/Volvo????? (Never mind, I already know the answer )

[Dick]

Originally Posted by nhdriver

You are right about the H.D. components, but reverse rotation is only used on one engine in a dual engine installation, so the props don't "steer" the boat on hard acceleration. Single engine installations usually have the standard rotation. Reverse rotation engines were much more expensive to produce.

Many straight inboard engines were reverse rotation until just a few years ago when the engine builders decided to eliminate them. Reverse rotation short blocks were going for a premium because they were getting scarce.

[TK]

Originally Posted by dodger1

Single-plane low-rise 4-bbl sounds like a 273 piece, but the heads?? And what's wrong with the Bayliner/Volvo????? (Never mind, I already know the answer )

It is too small, the hull don't take the bigger waves, it's too small, underpowerd, I hate outdrives already, too small, burns too much gas, too small, is a planing hull, too small, and not Mopar power.

[1973Swinger]

What dont you like about outdrives Bobby? Yours isnt a Mercruiser is it? If its an old OMC Cobra, I understand why you dont like it, they are junk. A Merc Bravo III or better would be a ton better, especially in big water.

[peg leg]

Is a killer good hull, as you know. The engine, by Chrysler standards, is probably a stock Mopar unit. They built really good, over-engineered boat power for many years. I disagree on boats not needing low rpm torque. That's how they get onto plane quickly.
Can you imagine the 5.7 in that hull? Zowie!

[TK]

What dont you like about outdrives Bobby? Yours isnt a Mercruiser is it? If its an old OMC Cobra, I understand why you dont like it, they are junk. A Merc Bravo III or better would be a ton better, especially in big water.

Too many things to go wrong, locks, u joints, just not as simple as a prop and rudder, and not as efficient. Mine is a Penta270. It works great.

I disagree on boats not needing low rpm torque. That's how they get onto plane quickly.
Can you imagine the 5.7 in that hull? Zowie!

Kinda, at an idle, there is, and never will be any load on the engine, the, as RPM's rise, so does the torque demand. For example, the AQ170 in my bayliner, will run 2000rpm barely off the idle screws, but by the time you get to 3000rpm, it is half throttle, and max rpm is 4000rpm. There is virtually no need for the engine to make any power before there is a load. The only way you would need the low end torque, is if the boat was being towed backwards.