Fish Regulator
Cadet
- Joined
- Jul 1, 2004
- Messages
- 20
What makes a marine motor diffirent than a regular motor in a car.
<br />SOME DIFFERENCES BETWEEN AUTOMOTIVE & MARINE ENGINES<br /><br /><br />For those of us in the marine industry, a common occurrence is to be questioned by customers about auto vs. marine parts. A common scenario is to have a customer ask for a replacement part for his boat. The part in question is a starter for a 350 cu.in. GM block. You give the customer a price, and he looks at you with a blank look on his face. He, then states (very angrily) "I can get one at the local auto retailer for $29.95". <br /><br /><br />In the marine industry, this little scenario occurs all the time. Many boaters are unaware of the difference between an automotive and a marine engine and their respective accessories. The most notable differences include the exhaust systems, the cooling systems, the electrical systems, and the fuel systems. Additionally, items such as heads and cams are usually different. For the purpose of this article, we will only be hitting the highlights on select systems. <br /><br /><br />In regard to the cooling systems, one of the major differences is found in the water-circulating pump. This is especially noticable when you have a raw water cooled engine. Unlike their automotive counterpart, a marine pump works in an open cooling system. This type of system is extremely corrosive to the pump. Therefore, the pump must be altered for longevity. A marine pump has a special ceramic seal, stainless steel backing plate, and a bronze impeller to resist corrosion. An automotive style pump, with its stamped steel impeller, would fail due to corrosion in a short time.<br /><br /><br />The electrical systems in a marine application are also extremely specialized. In an automobile, any gasoline vapors that accumulate will readily dissipate through the bottom of the engine compartment. However, a boat with its sealed engine compartment, does not have that luxury. Therefore, any spark could literally cause a boat to explode. All electrical components in a boat are either completely sealed or specially vented to prevent such a catastrophe. This includes the starter, alternator, distributor, and many other engine electrical components. <br /><br /><br />Carburetors typically have what is known in the industry as J type fuel bowls. These allow for the extreme vibration, pitching and yawl experienced on boats. This allows fuel to be drawn in exteme conditions and keeps fuel from being ejected from the carburetor barrels.<br /><br /><br />Heads and cams are set up for a completly different torque curve. A marine engine must develop most of its torque on the low end of throttle range. This allows for the ability to use a single gear transmition system. Think of it this way:<br />You get in your car<br />Start it up<br />Drive to the highway<br />Put your foot to the floor and hold it there for an hour<br />Its a little different, well for most of us.<br /><br /><br />Although we have only briefly touched on some of the differences between an automotive and marine application; hopefully, it will serve to remind us that there is a difference, and that the reasons for these differences need to be shared with our customers and friends in the boating community. Hopefully, when shared, this information can eliminate some of the "blank stares" in regards to parts, and maybe prevent some dangerious situations. <br />
I don't. The reply was in response to the reply saying only the cam , freeze plugs and head gaskets are different. i.e you can use car parts on the rest which is unsafe in my opinion and is why people like the coast guard specify different rules and regs for marine parts.why do you feel that reuseing all the correct MARINE PARTS on a rebuilt block would cause a saftey problem
The guy's first post already addressed that. You bashed him before you finished reading his post:<br /><br />Originally posted by Chris Myers:<br />I don't. The reply was in response to the reply saying only the cam , freeze plugs and head gaskets are different. i.e you can use car parts on the rest which is unsafe in my opinion and is why people like the coast guard specify different rules and regs for marine parts. [/QB]
My take is he is saying the only difference in the BLOCK is the cam, etc, etc, and you REUSE all of your 'marine' carbs, pumps, manifolds, etc.<br /><br />We are on a message board and many things are imlpied by comment writers that sometimes aren't picked up on by readers. Just a misunderstanding...Originally posted by poi9jkl:<br /> the only difference is the cam and freeze plugs and head gaskets. you reuse all of your carbs,pumps,manifolds, ect. I have done this and dont believe marine mechanics.