Difference between two diesels?

[Degree]

What is the difference between a marine diesel and a regular diesel engine?

 

[DaveNay]

</font><font color="blue" class="small">( What is the difference between a marine diesel and a regular diesel engine? )</font>

The Marine diesel has a crew cut. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Dave

 

[MicroPilot]

Possibly that they use the water they are in for cooling (a marine engine doesn't have a radiator) and are constructed with different materials to resist corrosion, and different water pumps.

This is just a WAG /forums/images/graemlins/shocked.gif

 

[Junkman]

I asked this of a friend that is familiar with marine diesels a while ago. He said that the water pump is different and the marine diesel also use water to cool the exhaust. Different components in the areas that are in contact with sea water, but he claims that almost every marine diesel engine can be converted to land use, but that land use diesels can't be converted to be used as a marine unit.

 

[MadReferee]

This past summer ShipShape TV had an episode on marine diesel engines. They took a tour of the manufacturing plant (sorry, I forget the make) and the interesting thing was that the block and the internals are the same for both marine and commercial engines. From what I remember is that the final paint and the oil reservoir were the only differences.

 

[phxraptor]

Marine engines also turn counter clockwise. At least most of them do.

 

[DaveNay]

</font><font color="blue" class="small">( Marine engines also turn counter clockwise. At least most of them do. )</font>

Wouldn't this just be a matter of which direction the starter rotates? Maybe the firing order needs to be re-arrainged too? I can't think of any physical reason any engine wouldn't function in the other direction without modification.

Dave

 

[Egon]

Sure-- an engine can rotate in either direction. For some it's pretty simple - for others it could get a tad complicated.

egon

 

[JATO_RaT]

OK Egon, I just have to ask. I see your signature picture and am trying to figure out what you are doing. I think back to when I was young and played with the little plastic army men. One looked like he was vacumming out on the battlefield. You resemble that little plastic fella. My guess is your out in the yard vacumming or possibly weed eating. Am I close? /forums/images/graemlins/grin.gif

 

[Docsknotinn]

I think that marine diesels can run clockwise or counter- clockwise. If you have twins you really need counter -rotating props unless you actually want to idle in circles ..... then you'd have to choose left circle or right circle ! /forums/images/graemlins/blush.gif /forums/images/graemlins/smirk.gif

 

[Egon]

Laying in the winter bread supply stock.

Egon /forums/images/graemlins/grin.gif

 

[v8dave]

</font><font color="blue" class="small">( . . .Wouldn't this just be a matter of which direction the starter rotates? Maybe the firing order needs to be re-arrainged too? I can't think of any physical reason any engine wouldn't function in the other direction without modification.

Dave )</font>

Have to change the cam shaft and distributor (fuel or electric). Need to have the intake valves open before the exhaust valves and the distributor would need to have advance in the proper direction.

Allison aircraft engines had two versions of the V12 for the Lockheed P-39 twin engine WW II airplane. The two engines rotated in opposite directions so there would be no torque/airstream induced limits in roll. That is it could roll equally well to the left and to the right.

And in the obscure and obsolete fact list is the Ford Flathead V8 introduced in 1932. Which had its crankshaft off set 1/8 inch to allow the rods to be straighter when starting the power stroke. I believe they undid this (i.e., centered the crank) when they released the 1939 version of the engine.

 

[daedong]

<font color="blue"> What is the difference between a marine diesel and a regular diesel engine? </font>

Not sure about the difference, but if you crossed the two you would obviously have a amphibious diesel /forums/images/graemlins/grin.gif

 

[bgott]

Most of the marine diesels I have experience with are saltwater diesels. I say this because engines destinied for fresh water use only might use raw water for cooling. Marine diesels use a closed cooling system with a heat exchanger cooled by raw water. You have the engine water pump that is the same as an automotive pump, it moves the water through the freshwater side of the system, and a raw water pump also driven by the crank. You can go to the John Deere website and see pictures of their marine diesels with the heat exchanger on the front of the engine. Diesels can have problems with cavitation on their cylinder liners under ideal conditions, there is no need to help it along by running sea water in the engine block. Most have water cooled exhaust. A dry exhaust, besides being a fire hazard, would heat the whole boat up and make it one miserable mother to work on. Some of them have a wet manifold and a dry stack. You need spark arrestor screens on the alternator per Coast Guard regulations, I believe. You can look that up on the CG website under electrical regulations. Some might counter rotate, most seem do the counter rotation through the gear box. All the Detroit Diesels that I worked on used automotive ( left, from the rear) rotation. Detroits are blower scavanged so to run backwards with any power you'd have to design a reverse rotation blower drive arrangement to get it to work. It's easier to let the shaft drive manufacturer deal with it. Detroits are two strokes, they will run backwards inadvertently but there isn't any power running in reverse. When I drove rock trucks in an iron mine I have backed into a berm, killed the engine and didn't kick in the clutch quick enough. The engine would start backwards and drive the truck forward in reverse gear. It's a freaky feeling the first time it happens to you. There is a possibility that someone spec'ed the engine itself to run backwards and they built a reverse blower drive, I just never saw one. There is a lot of weird marine propulsion equipment out there. I worked with guys that had 30 and 40 years experience and we would regularly run into stuff they hadn't seen before. One interesting engine I have seen was an all aluminum Detroit 6-71. They used them in WWII minesweepers. The minesweepers were wooden and they didn't want the engine triggering magnetic mines.

I forgot about keel cooling, it's still a freshwater system with a heat exchanger.

http://www.flagshipmarine.com/keelcool.html

 

[daedong]

That was a very interesting read. /forums/images/graemlins/cool.gif

 

[Bird]

Brad, I don't know hardly anything about marine engines, but even some, at least, of the gasoline inboard engines I've seen have the closed system and heat exchanger. About 20 years ago, I was visiting my brother in Anchorage and we flew down to Seldovia to go halibut fishing with a friend of his and we had to change out the heat exchanger, put a new one on the boat, before we went out. I remember my brother mentioning that it was not only to keep salt water from running through the engine, but up there, if you had the fresh sea water running through the engine, you'd never be able to get the engine up to normal operating temperature. /forums/images/graemlins/laugh.gif