# What is the difference in a car engine and a marine engine



## Ryandumas (Apr 17, 2005)

If I have a boat with a 5.0 302 ford cobra engine attached to a omc outdrive
Would I be able to take the heads intake exhaust ...etc of and put it on a good car 302 engine and run it in the boat or would there be some differences. I have a boat with a bad 302 and I have a good engine from a mustang any feedback would be appreciated thanks


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## lkmifisherman (Feb 4, 2004)

Although basically he same engine the tolerances on the marine engine are much tighter. You might get away with it for awhile but trouble will start to brew and the engine will let go. Imagine a rod coming out the side of the block and through the hull somewhere. What year engine do you have? I have access to a 74 302. It is volvo penta but the long block is the same. And it will fit bu changing manifolds, ect. over. I know I can get you a good deal on it.

lkmifisherman


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## jpollman (Jan 14, 2001)

I'm no expert but I can tell you that putting a standard automobile engine in a boat is a bad idea. A few years ago my father purchased a 24' Sea Ray. He used it for a couple of seasons then the motor crapped out. He didn't realize it at the time he bought it but we discovered that apparently the guy he bought it from put a rebuilt car engine in the boat. We ended up picking up a reamanufactured 350 marine engine and dropped it in. He hasn't used it much since then but it's been working fine.

I agree with the tolearance issue. I believe that marine engines are put together with tighter tolerances. The long continuous loads put on a marine engine make these tolerances much more critical. I wouldn't advise using a car engine in a boat. (Just speaking from experience)

John


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## jpollman (Jan 14, 2001)

I just did a search and found some info on the difference between a marine engine and an automobile engine. Here's a brief overview.


*Topic:* Marine vs. Automotive 
*Question:* Is There Really Any Difference Between a Marine Engine vs. Automotive?

*Response: *Contrary to what many people claim, there truly are several differences between the automotive engine and marine. These differences prevent automotive products from performing as well as the intended marine engine. Many people attempt to save money by utilizing an automotive engine rather than marine, however in our experience these situations rarely save money in the end. Be very careful with companies who claim to offer engines not being Marine Grade, but still being the same, or compliant, or some other fancy terminology. In the end the fact still remains that you get what you pay for. 

The freeze plugs are of a corrosion inhibiting material.
The head gaskets also utilize corrosion resistant construction.
The valve guides utilize corrosion resistant construction.
The water pumps are intended for a marine operating environment (seals and bearings).
The camshaft is designed to marine duty requirements as needed to move a boat versus a car.
The overall duty cycle of a marine engine is very different than that of an automotive application. When was the last time your thought of running your car at full throttle for a sustained period of time?
 


Hope this helps with your decision.

John


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## waterfoul (May 18, 2005)

There are MANY differences. The biggest being the cam profile of a boat engine is a lot different. You want the peak hp and tq numbers at much higher rpm's in a boat motor. No transmission to keep the rpm's down like you have in a car. Boat motors are always under load... there really is no coasting or cruising like in a car. How well does your car run down the road at 2000 rpm? My truck is at about 75 mph and loping along at that rpm. My boat on the other hand would not even be on plane!!

Also, the alternator, starter, and distributor are all sealed to prevent sparks on start up. Gas fumes sink INTO the bilge, right where all these sparking ignition components are located!! Never use automotive ignition components on a boat. Also, most boat motors use stainless valves and gaskets. Imagine putting steel valves and gaskets in a motor that would see salt water duty? Wouldn't last long at all.

You could make a marine motor out of your Mustang engine, but it would probably be cost prohibitive in the long run. There are a LOT of long blocks available out there...


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## Ryandumas (Apr 17, 2005)

Does anyone know of where I can buy a rebuilt marine 302 engine and about how much it would cost


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## adjusted3 (Feb 3, 2003)

Start here http://www.jasperengines.com/

They are one of the top names in the repower business. you can get a price quote right on their site and they will ship direct to you. Excellent warrenty. you get the block and you add all your own covers, carbs, etc. for your engine you are looking at about $2238.00

Mark


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## jpollman (Jan 14, 2001)

For my dads boat we ended up going to Booth Aarons in Berkley. They did a great job and I think he paid about $2200 for a 350 Chevy.

If you do a google search for "Rebuilt marine engines" you'll get LOTS of hits.

Here's one off hand :

http://www.rebuiltmarineengines.com/catalog.html

That site is showing a rebuilt longblock 302 for $1895.

Good luck !

John


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## waterfoul (May 18, 2005)

I beleive you can get a Recon rebuilt long block at Pep Boys or Autozone. Come with warrantees.


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## waterfoul (May 18, 2005)

http://www.lukenmarina.com/engines.htm

There is also a link just below this thread for Daddyo's engines. Might try them?


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## fishandhunt (Dec 14, 2000)

Another huge difference is that the marine engine may turn (crank rotation) the opposite way! I would bet that your boat engine turns to the left (CCW) while the car engine turns to the right (CW)! Check your flywheel and you'll see if they are the same or not. 


Good luck!


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## lkmifisherman (Feb 4, 2004)

I tried to pm you back...it says your inbox is full...time to clean house lol...


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## Ryandumas (Apr 17, 2005)

I tried to call the maid but no luck had to do it myself


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