Engine differences between normal car engines and i/o boat engine?

Question

Do inboard/outboard boat engines use the same engines as normal carbuerated cars do? Could I build a boat engine the same way?

Answer 1

Marine engines use the same block as car engines, they are "marinized" with water cooled manifolds, spark proof ignition systems etc. Some of them do have a different crankshaft rotation but that is really the older engines. Now counter rotation is handled in the marine gear (transmission).

Answer 2

The difference in auto and marine engines. They use brass freeze plugs on block. The camshaft and valve springs are different for the rpm range a boat runs in. Which also calls for proper jetting of carbuerator.. Water cooled manifolds and risers .The alternator and starter is marinized with a spark shield to prevent and spark from igniting gasoline vapor. the carbeurator has a return line that runs from fuel pump to carb airhorn so when the diaphragm in pump should break gas is recovered into carb by a piece of tygon tubing instead of dripping into bilge.
If some thing goes goes wrong and their is a coast gaurd or insurance investigation and an item is not found to be approved you could have troubles

Answer 3

The I force GMC engine is different in enough ways that the I tech 2.5 liter parts might not fit. Being almost metric threads and the inboard is almost always standard threads. I also have found the 1969 Chris Craft GM 327 cubic inch engines are just different enough to be frustrating. $100 carb kits instead 25 dollar kits and engine internals are just slightly different. If you plan to use a automotive gas engine build it up like a truck motor the trick is low end torque not high revs.

Answer 4

No, the marine engine has much larger water jackets to cool it. The marine engine will also dump the heated water into the exhaust instead of recirculating it through a radiator like a car engine. A car engine will over heat if you try to put one in a boat.

Answer 5

mark t has the most reasonable answer so far. If you already have an I/O and are looking to replace it, for the most part the engines are the same. Minor differences are: marine ignition and electrical parts (sealed so no ability for arcing spark), exhaust manifolds and risers, and freeze plugs made of brass instead of steel. If you're looking for V8s there pretty common and relatively inexpensive. Buy a rebuilt long block of the same model and all the marine parts from your old one will bolt right on to the new one.

Answer 6

take the time to go to a good marine repair shop and see if they have an old engine you can look at. you'll see the mains are larger, the crank is huge, the cam is huge, and there are balancers that cars don't have. very little similarities inside. boat engines are built to run 4600rpm all day long...try that with a car engine!!

Answer 7

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Answer 8

marine engines run in the opposite direction from car engines,, Install a marine cam and it's done, also reverse the plug wires in firing order