318 Detroit

I think one of the better running 318s I drove had 90 injectors in it, an air shift 4x4 and 4:11 rears in a 359 Pete.

I have no idea what fuel mileage I got, never crossed my mind to check back then... LOL

 

Once again you are wrong a 318 will pull 318 HP, I worked at a Detroit dealership for 9 years and 364 days, we dyno'd every engine and could pull 310 regularly and lots over 320, next time you are with a 318 and you wonder about low end power put the truck in low gear with the Maxi's on and hit the starter, it will drive off do that with any other engine.

 

They will idle up an incline that would choke down every other truck engine, mainly because each cylinder is hitting every revolution, not because of great torque. I liked that about mine. I could idle up to a dock anywhere at a super slow speed. I also owned a 6V92TTA # 335 that would pull and run circles around the 8V71N. If the block had been stronger around the main bearings on the 6Vs, they would have been great engines.

The HP ratings I quoted were from a chart I found.

[FONT=Times New Roman,Times]8V71 Detroit Diesel[/FONT]
Engine Specifications
Published in MOTOR DIESEL REPAIR MANUAL, 1979​

Engine
HP # RPM
Torque # RPM
Injector cu. mm.
Comp. Ratio
8V71N
242 # 1950
696 # 1200
55
18.5
8V71N
265 # 2100
732 # 1200
60
18.5
8V71N
289 # 2100
758 # 1600
65
18.5
8V71T
293 # 2100
892 # 1200
65
17
8V71T
320 # 2100
941 # 1200
70
17
8V71T
335 # 2100
967 # 1400
75
17​

http://home.ptd.net/~menear/enginespec.htm

The post I have found all seem to refer to bus and boat applications, which give the torque at a lower RPM because of cam timing. My truck had advanced cam timing and N65 Brown Tag injectors, and would not pull at all under 1800, it wanted to smother out and smoke. That's my experience. I know these engines will lug, because of all the buses with 4 speed transmisions. I also remember when I was young, watching all those busses boil black smoke for what seemed like five minutes with each gear change until the RPMs came up enough for the engine to operate efficent. The dyno may say one thing, but running down the road may tell a different story.

You had a dyno, and I don't doubt your results, just as I know how all the 318 engines I drove operated. I would like to find the specs for the 60's and early 70's 8V71N's, as they may be different from the later years of production.

The only engine I ever saw in the mid 70's that could lug to 1200 and still have plenty of power was a Mack Maxidyne with a 5 speed.

 

buy stock in an oil company!!!!!!
And every time you stop fill up the oil and check the fuel!!!!

 

I have my field service data book 8V71 that would be an "S" kit 2 valve, 55 injectors, at 1800rpm 236 hp, 253 at 2000rpm, and 260 at 2100 RPM.
With 70's injectors 275 HP at 1800RPM and 298HP at 2000 RPM, 307HP at 2100 RPM 321HP at 2300 RPM.
The 8v71N with 65 injectors 273HP at 1800 RPM, 295HP at 2000 RPM, 307HP at 2100 RPM
These are for 500ft and 85 degrees. All Detroit's have an option tag that gives you the HP and torque on it, I have dyno hundreds and they all would pull 82% of the rated levels. If they did not they were fixed until they did.
An 8V71N is spec-ed at 318 HP and will do it they have a no load speed of 2350 RPM, the torque and HP graph lines cross at 1550. 1200 to 1550 is were you drive it, and any oil leak is fixable and easy to work on!

 

A kit was available to return the oil coming out of the weepers to the crankcase. Most of us attached small hose to the weepers. The hose almost touched the pavement in the hope that the oil would stop blowing back onto the bottom of the transmission, drive axles and frame. Trucks with Detroits would drip oil almost from the entire length of the truck. I think most of it came from the weepers. Someone will explain why this oil from the rockers could not be returned to the crankcase internally.

 

I had a '79 KW with an 8V92TA rated at 440 hp, it pulled very well with the Cats and Cummins of the day. I ran west coast from MI and was rarely passed on the long pulls. A KT525 or 600 was a different story though

 

JohnP3 I read the rest of the thread, but had to come back to this one, when I first read this post, I thought different things about you,

1-I thought you were being the most sarcastic guy ever posting here.

2-I thought you were probably talking about the 318CID Chrysler V8 (sarcasm here).

2-I seriously thought that you have never even seen a 318hp 871, when you said that their full torque was at 1200 rpm and you drive them betwin 1300 and 1550 rpm, if you did that you would have to down shift back to first gear when going on an over pass, empty.
I have never seen any other engine that leak as bad as any two stroke Driptroy, if you tell a retired trucker from the '70s that the E series leak worse than the 318 871 they will think you will need more oil than diesel to work with that motor.

I had a tractor that came with a 318 871, and a 9513 gearbox, when it came time to in frame, we opted for a 290 BC Cummins repower, when we drove that thing with the 290 we were worried that the gearbox might not hold the extra power produced by the Cummins, that truck came alive with it's new motor.