7U D4 questions

Yes there are some changes to gain more power & speed like a different gov. spring & different fuel rack settings & RPMs. Also later D315s like the D4s used had engine balancers in them.I don,t have any late specs on the D4 but the D315 industrial engines go up in the book I have to 1800 RPMs full load & 1970 RPMs high idle (no load).

The 112 has 24 HP more than the D4 6U & 7U in the earlier days. THis is due as I mentioned before to different rack settings & different gov. springs & RPM setting. The D4 is 1400 RPMs full load & the 112 is 1800 RPMs full load. D4 HP is 51 & the 112 is 75 HP.Rack setting for the D4 is .200 with a 5F6413 spring & the 112 is .350 with a 5F1940 spring & both are with a 9F4113 counterbored fuel nozzle.

Hi Jim,
The grader followed the set up of the industrial, marine and electric set specifications for more power. It wasn't until 1954 that the balancer was utilized.

SJ,
I don't follow you on the 9F4113 counterbored fuel nozzle. These being the capsule type injectors.

Rack setting specs attached:

OM, I just turned my high idle up to 1,600 without messing with any thing else. Am I asking for trouble by doing this? Or just not making more power? But usually I don't run it faster than about 1,300rpm so the hydraulics aren't so jerky.

OM, I never really knowed what changes there was in the counter bored nozzles from the other ones but usually what I remember the tips did have a counterbore where other ones had a flat end on them. Take the 212 we,re talking about they list both nozzles for the same engine & the 9F4113 C.B. nozzle in that engine uses the 5F1940 gov. spring but the rack is set at .350 & the high idle is 1980 RPMs.The 4F4236 regular nozzle is listed at a .235 rack setting & 1950 H.I. & it also uses the 5F1940 gov. spring.Both setups put out the same HP at the same full load RPMs of 1800. Most the nozzles or replacements were the counterbored tip style as I remember.I guess we,ll have to ask the big yellow father where the changes come in, that was our joke when we were working at the dealer.The info (specs), I got them from a Cat rack setting book that I have using the 3H1690 rack setting gauge which is what I always used.Your question got me to thinking, well what is the difference in the two nozzles but there has to be some internal change I,m sure but never saw the differences or don,t know where to find an answer.