Whats the difference between marine and automotive engines

[hawkster0001]

I was just curious to know, i know about the cooled headers, and osme parts being made to last longer, but beside that are there really any other differences?

[kartman]

not really. the marine engines used to have stainless valves, but that is pretty much standard all across the board. the cam's are cut a little different. but right now i have an engine out of a truck in my boat, and it runs great.

[hawkster0001]

so ddi you use marine headers, or the trucks ones? can you use normal headers from a car?

[DRAGON88]

On top of what Kartman said, the engine electrics are suppose to be sealed and non-sparking.

[kartman]

i used the marine exhaust manifolds, and the marine fuel injection and ignition unit. and yes, the electronics all are sealed so if they fail they dont blow up the boat if their is gas fumes in the engine bay.

[NKCrider]

dont forget that that the parts for your boat cost 2x as much because of the word "marine" on them

[kartman]

NKCrider, i think thats the biggest difference. when i put my engine in, the truck distributor and the marine one were exactly the same. same part number cast in them except for a M in front of it.

[hawkster0001]

yeah there all supposively made too last longer since you can posibly be out 2 miles from shore and you dont want your alternator dying there, but i always look up 87 mustang 2.3 when replacing parts like wires and distributor and such just because there the same engine

[gx205]

Most all "marine engines" have a different block than standard automotive engines.

The walls are a little different, but the main difference is the main bearing mandrels. main seals, and the crank, due to more tourqe on a marine engine vs standard automotive..

Just about all of the other add ons are basically the same except that they are sealed better.

[kartman]

gx205, look up part numbers. The only ones that are different are the 4 cylinder ones. And that is because the motor mounts are moved to the front of the block. Yes it is true that in the past they were different to a point, all the new gm motors were pulled right off the truck line and sold to the industrial and marine industry. This is mostly because gm no longer offers any of the traditional motors in trucks. (5.0, 5.7, 7.4, etc)

[gx205]

kartman you could be right about all the newer blocks, as my experience is from motors 2005 and back. I haven't really worked on any thing from that era up.

As far as 4 cylinders, there's a whole lot more than just motor mounts moved. In fact the 4 cylinder boat motor is not even the same motor offered in cars.

The ford 4 cylinder is actually half of a 460 v-8 block.
A chevrolet is a completely different block also.

[cadunkle]

Brass freeze plugs (vs steel in automotive), head/intake gaskets different (to resist rust). Larger main/rod bearing clearances due to lower temp/higher load of marine engine. Often the pistons will be forged instead of the cast or hypers found in most cars, this allows them to take more abuse, predetonation, etc. before failing.

I have a car engine in my boat and it's really no big deal. I swapped over the marine timing cover and water pump as well as installed brass freeze plugs. I didn't replace head or intake gaskets. No big deal unless the boat sits in salt water all the time, in which case a close cooling system with heat exchanger would be prudent anyway.

[hawkster0001]

well since mine is from 87, it has a ford 2.3 with the omc, about three years back we had an 87 mustabg 2.3 and as far as we could tell there basically the same engine. which got me to thinking, in the 80's ford made a svo version of their mustagn which was a 2.3 cammed turbo and it put out 205hp stock, there stock 2.3 had 80 or so, hahhaha turbo boat?

[RUSSIAN]

All I know is that I had to get a "marine" water pump that was $150, because the regular 350 water pumps didn't have a slight indention to clear the timing chain cover bolt, didn't learn about it until I installed and reinstalled an identical looking one 3 times, then looked at every pump I could find and sure enough only the boat store had the right one for 5x as much

[kartman]

is it a reverse rotation engine?

[RUSSIAN]

Im pretty sure its just a standard gm 350

[ifimust]

I know this thread is a little old but did anyone actually drop an automotive ford 2.3 into an marine OMC set up? Mine is toast and I'm probably going to give it a try soon.

[Bambamski]

I thought that Marine engines were made to rev higher and longer then a regular car engine? I think it was a buddy that basically said they're made to pretty much redline for 10-15 minutes at a time where the car would blow up doing that.

Not sure if that's true?

[Nor*Cal]

http://www.boatdesign.net/forums/diy-marinizing/auto-engine-marinization-650.html

[ifimust]

Thanks for the link. I have a 2.3L OMC and was planning on using the boats ignition system (distributor, electronic ignition, etc.), cooling system (thermostat, exhaust manifold, water pump), fuel system (carb flame arrestor etc) from my old dead engine, installing them on a not dead old ford engine from a car which, based on what I have read, is the same as the OMC engine and replacing the freeze plugs with brass ones. Seems like that is the much of what is suggested especially since I have have no interest in trying to wakeboarding in the ocean, its all calm freshwater rivers and lakes for me.
If anyone has tried this and had success or failed miserably please let me know otherwise I'll post how it goes.

[Nor*Cal]

Also, you don't want any metal in your head gaskets if marinizing.