What makes a marine engine?

[bones774]

I'm just getting involved in boating and know that the basic blocks are GM or others major auto manufacturers but what then makes it marine? I know auto engines spend most of their life at relatively low RPM and boats are just the opposite, so why should a GM block and pistons perfrom well under marine use?Whats old for a marine unit? how many hours?
any insight appreciated.
Thanks

 

[idrownworms]

Re: What makes a marine engine?

lets see, camshaft, manifolds, carbs. Depending on the motor it could also have different heads, pistons, connecting rods, crankshaft, heads
The RPM range has to be greater i.e. tons of torque in a boat than a car, try to take off in highway gear in your car.

 

[tashasdaddy]

Re: What makes a marine engine?

also all electronics, is shielded against spark for fire control. exhaust is water cooled.

 

[JB]

Re: What makes a marine engine?

This thread will probably do better if it is in the I/O forum instead of OUTBOARD.

 

[5150abf]

Re: What makes a marine engine?

They are also balanced more than a regular car engine, a block is a block but all the parts inside are turning at a much higher rpm and need to be more balanced than a normal car engine.

I am sure if you pulled the engine out of a Camaro and put it in a boat it would be short lived.

 

[proshadetree]

Re: What makes a marine engine?

Just got through putting a 96 truck 305 in a bayliner.Block same,crank same,rods same,pistons same,cam different,heads same,valves and springs same,Oil pan different,better baffels on marine and a wind age tray bolted to main studs.If you match part numbers and do a cross reference most swap out.Can you put a automotive cam in a boat yes but if you get to much overlap with a water manifold you can get it in cylinders.Not a problem if your running headers that stick way out of the water,illegal around here but you might get by with it.On the outside of engine dont use car parts they will work but are not safe in a closed compartment.Stay with marine dist,starter and alt.Now if you have a open engine boat.You can get away with a lot more.Check state laws first.In tennessee it said you must have a engine cover,Like I said you might get away with it but what if you dont.