Older diesel engines that smoke?

I suspect that it's a combination of excess fuel and lower compression.

Usually white smoke is oil consumption and black smoke is fuel.  I have a Massey Ferguson that has blow by and puffs white smoke from the exhaust.   

Mostly design of the system.Old Perkins smoked more going down the road than in the field.

many years ago when we were doing in field fuel testing, using a D21, we put plain old #2 fuel in it. pulled it hard. Smoked like crazy, drained all the fuel and put in premium #2 fuel. guess what--no smoke while pulling it hard. According to the guys in the know that black smoke is unburned fuel going to waste. Fuel consumption per hour with the good stuff was quite a bit lower. Been 40 years ago and I cant remember the actual numbers.

As to the AC engines, both the farm engines using the 301 and the 4.33 as well as the 426 heads  were designed as natural aspirated units at first.  The heads have a design which swirls the air and mixes with the fuel.  The addition of a turbo and the resulting increase in power found the engines just could not burn all the fuel as the hp and rpms increased. There was never any change to the cam shaft as AC got burnt trying to hold the intake open longer on the D19  - they had to switch all the cams back to allow them to start in cold weather- so they never improved the cam profile for this and maybe other reasons.  At approx. 1980 the engines were switched over to Bosh injectors.  In the F2-3 combines the smoke almost went away - these units had approx. 20# of boost. The M3-L3 had a much reduced smoke due to the better , lower spring nozzels  that atomized the fuel much better due to increased pressure but mainly a lower inertia weight of the moving assy which opened and closed quicker in most folks opinion. I have posted before on this, but some engines using TO4B-80 and -90 turbo's  had a one size smaller exhaust housing causing a 2-3 # boost increase.  These are really hard to find now and very expensive.   The std 426 to4b90 used a .96 A/R ratio - one size smaller was a .8 and the 301 used a .69 A/R on the to4b80 with the next size smaller being a .58.

We had a 7580 that smoked like a frieght train,, neighbors always knew where we were working ground at

Never heard of them timed that high! 38_42is a bunch

The timing on the 7080 & 7580 was 42degrees full advance. The pump start timing was 24 as i remember. The pump advanced to 42 at high idle no load & drooped back to 38 under load. They still smoked like a steam engine. 

I enjoyed reading through the replys. Learning a lot on this site.

nick, if your only getting 5# of boost - you have a serious problem - probably a hole in the tube going to the boost gauge - or a bad gauge - other wise you only have about 50 hp....

Plowking77 wrote: We had a 7580 that smoked like a frieght train,, neighbors always knew where we were working ground at

Edited by CrestonM - 07 Jan 2017 at 1:47pm

"Boost" is a diesel engine's intake air pressurization. It is graduated in pounds. The engine's hot exhaust gasses spool up it's exhaust side of turbo. Each cylinder's burned fuel air mixture creates hot exhaust gasses. "Spool up" means your engine's load is increasing & rpms (govern
or reacting) increase to match load. Hence, faster engine rpms equals more hot exhaust gasses, which in turn spools up (turns turbo faster).
As the turbo's exhaust side turns faster, so does its intake(fresh air) side turbine. When the engine is under a load(hill, heavy clay plowing, heavy crop threshing, etc..), engine's exhaust temps increase, spooling up intake pounds while engine rpms slightly decrease from initial load, but then are being increased by reacting governor. . Boost is this extra pounds of intake air available while load dynamics stay. When loads go away, so does the boost.

AC7060IL, that's a good understandable explanation of how boost works. I always wondered about that as well.