I am ignorant about these engines. There is one for sale close by and I'm thinking I can use it down the road. It is a 318 model, does that mean 318 HP??? Would this be an OK engine for a 50K lb excavator?
318hp, n/a 8v71. Seems a little big for a 25ton to me.
I have driven trucks with that motor and they always felt like a lot less than the rated 318hp. a 290 cummins small cam would beat it like a drum, and they were no ball of fire.
they're converters. they convert diesel fuel into smoke and noise. Not alot of power. I always thought the old Detroit's made great stationary and marine engines, not so great truck engines.
an old owner operator told me when I was a kid that 2 stroke motors were fine for model airplanes.
Agree , 6-V 53 Detroit or in line 4- 71 would be perfect for a 25 ton hoe .
We used 6-71s and 8V-71s in our log trucks hauling 100,000 lbs gross of tree length wood for years. Granted they were only geared for 60 MPH top but they started well in the winter and ran forever. I have a 8V-71 in my old slasher truck that still purrs like a kitchen. Its a 1974 International with a 10 speed road ranger behind it. The 6-71s were in 9500 Series GMCs and got about 5.5.MPG on fuel and the 8-71s in the Internationals got about 5 MPG both average for truck engines of the days. These engines worked great for the short haul. They seemed to have trouble as over the road engine. Never worried about a driver being lulled to sleep in these. But to answer your question, Yes, the non turboed models were 318 HP.
Noisy, tended to leak oil, but pretty reliable. They can be turned either direction fairly easily I believe. As Chevota84 mentioned, the 318 was the horsepower for an 8V71 naturally aspirated engine. The turbo version (8V71T) was 350 Horsepower if memory serves.
I picked up a blower for a 6-71 a little bit ago. I thought a 72 Challenger with a supercharger sticking out of the hood would look nice. However, being short the 72 Challenger for that project, will this blower go on and help the 8V71? I have no idea what I am going to do with this engine. I just know it is cheap and I want to learn more about DD 2-strokes.
HP ratings for the 53, 71, 92, & 149 series engines are based on injector size. The 8V71 could be de-tuned and have 55mm injectors (250 HP) or hopped up to 333HP with the 75 mm. It had 304 HP with 65mm's which was very common. 70mm's produced 318HP. Of course if the valves and injector rack was not set just right, power faded. Another thing to consider is size and weight when comparing the Detroit to Cummins. The 8V is about 1000 lbs lighter and is a 568 cubic inch engine while the Cummins is 855 in.
Greyhound bus seemed to like them in their over the road rigs.I personally thought that they were a work of art in performance and otherwise considering when they were developed and their competition at the time.Just looking at one with the OHV cover off has got to get your attention.Hats off to GM,too bad that they did not include some of those design implementations in the Allison V12 and maybe we wouldn't be riding behind those Merlins in our P-51s.Ron G
They all have superchargers, they won't start without them.
OK, guess I'll have to look around for a turbo to add. 72 Challenger project is back on!!
I've been told that putting a turbo on an n/a Detroit requires internal parts, but I've never tried it.
You should advance the timing by one tooth if you are going to add a turbo. It requires taking the flywheel housing off and looking at the marks on the idler gear. You will see 4 gears under the cover. Rotate the engine until the cam shaft marks line up and then remove the idler. Line up using the "A" mark and be careful to align the oil supply hole with the block. There are three hidden bolts under the drive covers so be sure to look at the book or find someone who can tell you where to look or there is a chance of prying until the housing breaks and finding them that way. There are also places to use copper washers that will cut down the oil leaks. Be sure to check if the idler gear bearing is worn. If you are tore down this far, replace it. They make a real mess if when they fail. New gears, bent parts, and so on.
The old 2 stroke detroits were a great engine in their day, but like most things, their day has past. We call it WW2 technology, which is about what it is. They are simple to fix but lately finding QUALITY PARTS can be an issue. They have a limited power band, drink fuel, leak oil everywhere, noisy. NOISY, I'll say it twice because they are loud!!!! We have replaced any of the 8V71's that we were still running with a series 50. In fuel savings alone the pay off will not take to long.
There are no two cycle normally aspirated Detroits
No turbo is n/a in Detroit speak.
Here is ours on the dyno, sadly we have an issue with our water pump inhibiting us from loading this engine all the way down till the manifolds glow red like we used to. 1978 8v92T Tailored Torque. 435hp https://vimeo.com/124353152
The combination of a 2 stroke and V-8 makes for an engine with not much torque, especially at low rpm's. They will make horsepower, but will seem underpowered compared with a 4 stroke inline 6. The secret to horsepower is never let the rpm's drop. Keep it revved and it will move, but if you lug it even a little, forget it. The old joke about a Detroit in a truck was that you should slam your hand in the door when you get in, so you drive it in the right frame of mind. On the other hand, they would last in applications that would kill the 4 stroke engines of the day. On the rigs, the constant cycling from idle to full throttle, then back to idle, would overfuel the 4 strokes and wash down the cylinder walls, diluting the oil with fuel, leading to premature failure, while the 2 cycle would do this with few adverse effects.
If you have an interest in the 8V71 and it's cheap ............ What the heck ...... Buy it , drag it home & get it running . If it smokes or runs poor then overhaul it . Sounds like you are mechanically inclined & enjoy a challenge . If your like me you will eventually find something to install the engine in . Go for it Bro :thumbsup I know I enjoy operating Detroit's and the challenge of the...................... Occasional break down http://s1016.photobucket.com/user/td25c/media/100_2826_zpsd79660df.mp4.html?sort=3&o=23
There are almost zero left around here. Maybe one fire truck. I was working in a boondock county today and I heard loud noises where I thought somebody was doing burnouts in the street. (It was snowing.) After a couple minutes it finally clicked it was the road dept. with their Detroit powered snowplow running through the gears. It sounded just as awful as I remember back in the day.
I was alway been told that when you put a turbo on a Detroit you have to retard the timing one tooth. I worked on boats some in the service and all the slant 6/71 engines ran N65 injectors and advanced cam timing. I was told the blower on a Detroit only gets enough air in the cylinder to equal atmospheric pressure so the manufacturer called it naturally aspirated. What I saw with the 2 strokes was that they liked flat land but put them in the mountains and the driver looked like he was rowing a boat by grabbing gears. More than once I've seen a skidder come out of the brush just to get a loaded truck moving. The 318 didn't have the torque to get 80,000 to move in the mud unless there was a deep reduction in the gear box.
The reason this happens is that the old mechanical unit injectors inject so much fuel per stroke at full rack no matter what speed the engine is running. Therefore to maximize the amount of fuel burned per second you had to run the engine at top RPM because that means more injection events per second. The competition in the Cummins PT system was quite the opposite as the fuel was simply metered through a hole and when the plunger came down it got injected no matter how much or how little was there to inject. Therefore the fuel delivery per second was more or less independent of the engine speed which meant that the torque went up rather than staying constant as the engine ran slower. Cat of course used independent fuel injection pumps which are another animal still. Some Detroits had "TT" in the model which stood for "tailored torque" which I assume was a more complex governing system that might have allowed the engine to have some torque rise but I can't say for sure. The later model electronic "DDEC" ones used the computer to time, fire, and meter the injector and the plunger was just there to provide the actual force. DDEC engines have a torque curve that drives pretty much like any contemporary four-cycle although the RPM is a little bit higher on the scale than a comparable Cat or Cummins. DDEC are also turbocharged as well as most of the higher hp prior generation.
And the skidder probably made more noise than the truck with Detroit engine . LOL ! Timberjack or Treefarmer skidder with 4-53 was common in my area .