Two stroke diesels

[Alan Reagan]

The two cycle engines until recently have had an advantage in the scavenging phase. They (with the help of a fast moving turbo or supercharger) can move air through the cylinder more efficiently thus keeping the possibility of a burned piston or rings to a minimum with slow burning fuel.



As far a power, as has already been mentioned, the two and four strokes are pretty even. You find a lot of two stroke engines in marine applications because of their ability to come up to the desired operating speed, very quickly in fairly stable load conditions. I see a lot of two strokes in tugs. They come up to speed fast but leak oil like crazy and burn a lot more fuel compared to their four stroke brethren. They will crank and run backwards. That's how a ship gets into reverse. Stop the engine, change the valve timing, and crank in the opposite direction. Most ships are direct drive, no transmission so the engine controls the direction of the prop.



The most common diesels we'll see that are two stroke are the ones in locomotives. They are two stroke EMDs. Need lube oil. On a ship, they will add it several drums at a time to replentish.

 

[MMiller]

Back in the '80's farm crisis my dad started driving semi to add to our income. The truck he drove was a '70's frieghtliner cabover with a 2 stroke in it. It ran good but it had lots of cubes. It was a 8V92 plus it had the optional turbo on it running in the neighborhood of high 400horses. He ****** off ALOT of cat and cummins truck drivers becaus it would flat run. Granted it was hard on fuel but at that time 4 mpg was great any way. I still know where the truck is and keep telling dad we need to get it for our farm but for some reason he keeps saying NO. Then mumbles something about his ears are still ringing from when he used to drive it!!!

 

[therabbittree]

hey cool thread ok the cfi twin engine drag racer does have 3 turbos staged for each engine. . but the engines are not n14's but signature 600's dual overhead cam engines... i saw the truck run at quaker city ohio this summer and man it rocks!... as for the 2 stroke debate. . the main reason any of the racers used the 2 stroke is weight. . the detroits weigh less then a similarly rated 4stroke... the torque is down from a 4stroke but revs are higher so like one of you guys said in the thread you do run em like you stole em. . foot to the floor. . ha... and you can run a 4stroke diesel backwards too. . i've done it on a mack 300, backing up loaded heavy full of salt during a stockpile operation. . it lugged down and just as i stepped on the clutch it must have reversed ,ha it sounded a little weird, but what did it was, when i went to drive away the truck was trying to go backward ha. . i had 13 speeds reverse and 2 forward!. . i just drove away from the pile in reverse and stopped the truck, it restarted fine and ran good in the right direction. . i guess it proves the wetline worked in reverse too ha...

later

deo

\x/ hillfolk!

 

[therabbittree]

hey cool thread ok the cfi twin engine drag racer does have 3 turbos staged for each engine. . but the engines are not n14's but signature 600's dual overhead cam engines... i saw the truck run at quaker city ohio this summer and man it rocks!... as for the 2 stroke debate. . the main reason any of the racers used the 2 stroke is weight. . the detroits weigh less then a similarly rated 4stroke... the torque is down from a 4stroke but revs are higherso like one of you guys said in the thread you do run em like you stole em. . foot to the floor. . ha... and you can run a 4stroke diesel backwards too. . i've done it on a mack 300 backing up loadced heavy full of salt during a stockpile operation. . it lugged down and jsut as i stepped on the clutch it must have reversed ha it sounded a little weird but what did it was that when i went to drive away i was trying to go back ward ha. . i had 13 speeds reverse and 2 forward!. . i just drove awy from the pile in reverse and stopped the truck it restarted fine and ran good in the right direction. . i guess it proves the wetline worked in reverse too ha...

later

deo

\x/ hillfolk!