1-71 Detroit Diesel (GM)

Sooty Jim

New member
Odd, isn't it? You can find chapter and verse on most of the other 71 series... the 2-71 being a possible exception.

Was trying to get an estimate at least based on old Diesel Progress magazines and such, since they usually have a big section on GM. The earliest I found was 1949 and the 1-71 wasn't listed. Wasn't in a '53 or a '55 either, but those are all I have been able to access so far.

Waiting to hear back from K-Tron. If no documented data is available, then I can present the best educated theories. As theories, of course.
 

Sooty Jim

New member
Since you guys have the 1-71 manuals, were there different power ratings? Mos of the G models I see say 15 hp. Some of the spec sheets list 10 hp and one I saw, and it has to be a misprint, says 34 hp. Were there different rpm ratings, or where they all 1200? Most of what I have seen show 1200 rpm but what about 1800. I am most curious about the Marine version and if it had a higher hp/rpm rating.

Diesel Doc- In one of the earlier posts you talked about a Mike 8 (LCM8) with a pair of Quad 6-71s. Are you you didn't mean a pair of twin-packs? I was a U.S. Army snipe that served on various U.S. Army vessels during the Vietnam era and every Mike 8 I saw had two twin-packs. Some of the last ones had a pair of 12V71s, or were repowered that way later. There was barely room down there for two twin-packs, let along two quad-packs.
 
Jim, the manual info that we have is for a 1-71 emergency generator. Max HP rating 1200 rpm 20. Continuous HP rating 1200 rpm 15. Max torque 87.5 at 800-1000. Compression ratio 16:1. Displacement 70.9 cu in. Continuous H.P. rating B.M.E.P. lbs/sq.in. 70. Max torque. lbs ft. 87.5.Compression ratio 16.1. Fuel consumption lb/BHP hr 0.50. NOTE: The flywheel is heavy, it heavier than a 12-71 or 3412 cat wheel. I will weigh it before i put it on. You are right about the LCM8 I worker on a old wooden tug once that had two quads. AL
 

Sooty Jim

New member
Got it, Doc, thanks. Talked to K-Tron on the phone last night and read me chapter and verse from his manuals as well. I am much clearer on many things 1-71 now.

I saw a pair of the quads in a wooden hulled minesweeper that a guy was turning into a yacht, though I don't think they were original to the vessel. Seems to me back in my Army snipe days I saw a single screw vessel with a quad installation. It was classed as an FS but it wasn't the traditional FS (the ones like the Navy AK). It was old. And so am I now and I don't recall the details.
 
I noticed stamped on the brass nameplate on the flywheel housing there were some small markings after the serial # I magnified and inverted the tag and it reads USN. The letters were stamped on top of each other. I guess this verifies it was made for the NAVY. ALIMG_1838.JPG
 

K-Tron

Active member
Al, this forum must think you are south of the equator, everything is upside down! :rolleyes:

Ive seen "$N" many times before on these tags, but never made the connection to the U.S. Navy. The "U" is usually stamped so lightly you cannot tell it is there. Perhaps that is because the stamp was one piece with three letters on it and the flywheel housing is round. Yours has a much more pronounced "U" than mine does.



Chris
 

mschreiber

Active member
Was "U$N" stamped at GM during assembly? Photo below is my Cat engine tag with "UanchorS". This engine was built march 1940. I've seen this same stamp on other equipment other than Cat. I thought the Navy stamped it when received?? just putting it out there:O
After looking again at Al's photo that ain't a dollar sign……. it is some kind of 1 piece stamp.
 

Sooty Jim

New member
I am getting conflicting dates on when the 2-71 started production. Everything I have says the 1-71, 3-71,4-71 and 6-71 started at the same time in 1938 but the 2-71 started later. What was "later?"
 

K-Tron

Active member
The 2-71 was "later", with a start in production in 1940, one and one half years after the 1-71, 3-71, 4-71 and 6-71 engines. The first 325 2-71's built utilized a rectangular port liner, specific to this model engine. My 1943 parts book shows that the 5153777 liner was already superseded by that year.



Chris
 
Jim, Detroit Diesel published a field service data book that had a engine serial # guide section. I "had" an early one back in1966 (green cover). It listed each DD engine by series and number made in the listed year. The data book i have now was published in 1995 (white cover) It covers engines from1972 through 1993. The older the data book the further this info goes. The 2-71 listed in my current book shows by1972, 85,087 had been made and the last one was produced in 1986, 106,233. I don`t know how far it goes back in the original book. Anybody out there have an older publication? P/S Jim I was a SNIPE in the COAST GUARD. Didn`t know the ARMY had SNIPES. Why not, we did the same job. ALOHA AL
 

Sooty Jim

New member
In many ways, the Army marine branch guys and the Coasties (I capitalized it at least ( : < ) were very similarly piratical. I know this because my best buddy at the time was a Coastie and I actually spent some time aboard the Cuyahoga where he served. You may recognize the name as the ship that was out training on the Chesapeake in the late '70s, turned in front of a tanker due to a navigational error (Academy Training Cruise) and was struck and sunk. Lovely old cutter. IIRC, she had GM diesels, 8-268-As, I think. I think all the guys I knew in her were gone by that time but 11 aboard were lost.
 
K-Tron,Chris,Looking at your pic of the 2-71 liner item 18. Are they o rings? The liner looks undercut above and below the ports like a wet liner. A dry liner needs good liner to block contact to dissapate the heat of combustion. Have worked on a couple 2-71`s but never had a liner out. AL
 

K-Tron

Active member
A friend of mine refers to the early 2-71's as a "wet liner" engine. The lack of a machined groove for o-rings tells me it is for a dry liner engine. I have never seen the matching block. I will send you a picture of said liner by email. It sure is interesting to see the progression of the Series 71 over its 80 year life span.

Chris
 
Chris, Detroit 53 & 92`s put liner seal grooves in the block. Cat & Cummins grooves are on the liner. Only the top of the 53 & 92 are wet. Looks like the early 2-71 liners were wet on the top and bottom. The liner seals would have to be above and below the ports, also one would be at the bottom to keep the coolant out of the crankcase. Does your parts book show two blocks and another liner for this engine? AL
 

K-Tron

Active member
Nothing like a good old 2AM memory lapse. My book is dated May 1943. It only shows block #5159856 for the 2-71. Since the "wet liner" was already superseded I imagine the block was already changed and called out in an earlier parts book. What that original number might have been is anyone's guess. We'd need to find an earlier book for the 2-71. I neglected to mention that the 5153777 "wet liner" also used (6) 5153420 seals. They look like flat shims at the bottom of the liner....they are designated as #18 in the image I posted above.

Chris
 

Sooty Jim

New member
Hi Guys- Finished my article and shipped it but want to say thanks for the help. All you guys, especially KTron, got me up to speed very quickly and I appreciate it. I'll let you know when it goes to print. It's for Diesel World magazine. I have the site bookmarked so I may pop up again.

Jim Allen
 
Information cast into the backside of the radiator housing. Not only did the Young Radiator Co make the radiator but the housing also. The core is in bad shape and i am going to get it recored.IMG_1855.jpg

IMG_1856.jpg
 
Crankshaft,camshaft and balance shaft installed. The gear train is on the front of the engine. Because of its location the left hand timing marks are used. The crankshaft rotates clockwise looking at the front. Oil slingers are on both ends of the shaft in addition to oil seals.FullSizeRender.jpg

FullSizeRender (1).jpg
 
Top