The nozzle for the ser# you gave is a OR-3422. The piston group that came in that engine are 7N-3516 (1W-9372 Piston), which are the same as late 92U A models and alot of 4MG engines. The OR-3421 will make it a 400HP. That nozzle will work fine....just make sure to use the matching washer under the nozzle. I think the 3422 is like Cody said, an economy engine like 310HP, which has a thicker washer under the injector. Don't want to retard the timing.I'm looking for info about #s 0r3421 and 0r3422. Whats the difference between these, spray angle etc.? Thanks for any info.
Tony will know more about this, but here's my theory. I've never seen anything other than a 310 or 330 with the thick washer. Yes, the thin washer will advance the timing and should clear up smoke.Sledman: Thanks for the info. The engine ID tag says its a 400 - AR# 4w4109. The exhaust has always seemed to smokey to me and there's a lot of soot as well. Pump, timing etc all stock. The injectors tested good and have the thick washer. Do you think the oR3421's with the thin washer would clean it up?
The truck is Kenworth, I'm second owner, everything original, have all records since new.
From what I can find it was one of 16 built. First one with this arrangement was 7FB00001. Odd. First B built. Fuel setting in .3mm below an 0T4444 hence the 390. Cam is a 24* cam grind for the 3421 arrangement number, but timing pin hole is offground a couple degrees down. Rated at 30% torq rise so it's supposed to be castrated from the start. Your serial doesn't even show to be built in that line, so you just may own a confusion motor.Sledman, Ynot Thank you. I've been trying to figure this out for a while. The parts book breaks the 7FB in 4 sections; Paccar, Ford, Freightliner and all except the above. My AR# is found in the all except section even though the truck is Kenworth and the engine is original in the chassis. Since work is slow I had time to look at alot of AR#'s in the parts book. Mine is an oddball, (kudos Ynot).
All the others used the 3421's and had the exact same guts as my motor. I dug down to the breakdown of the inj. pump group and found one difference.
The 3421 motors were all matched to the 4w2548(7w3100) pump cam and the 3422 motors were matched to 7L0006(7w3102) cam. I don't know what difference is between these cams. If I switch to the 3421 and thin washer is there something I might be overlooking here?
I knew that but 3421's only come with the .050 so no biggy.Installed 3421's and pin timed to 24* static. Eliminated smoke and lowered
pyro 200*. Can't imagine WTF Cat was thinking with previous setup. Truck
is much more pleasurable to drive. Can't thank y'all enough.
Sledman, the thin washers are .050 thick ones are .125". Ynot, I've got those beerz and will enjoy one in your honor!
:bangtony i believe its a little easy to understand :bangthe 3421 is for a 425 ,3422 is for a 400 a 3423 is for 350 a 3424 is for a 320 a 3425 is for 300 and a 3426 is for a 280or something like that, but my question is n:shrugs i never heard that a guy used a 3418 or 3417 is this for more hp or was it the first models for a b ?and what is the difference between a fuel nozzle and a fuel injection nozzle As ,i see them the same :thumbsupI knew that but 3421's only come with the .050 so no biggy.
And thanx my man. Now max the rack from the tech section and you have a horse!!! eelout :happymugs
Pichu....the 3421 is a 7FB 400 nozzle, the 3423 is a 4MG 425 nozzle. The 3422 is 350....I think:bangtony i believe its a little easy to understand :bangthe 3421 is for a 425 ,3422 is for a 400 a 3423 is for 350 a 3424 is for a 320 a 3425 is for 300 and a 3426 is for a 280or something like that, but my question is n:shrugs i never heard that a guy used a 3418 or 3417 is this for more hp or was it the first models for a b ?and what is the difference between a fuel nozzle and a fuel injection nozzle As ,i see them the same :thumbsup
Yep, my 7FB 400 calls for 3421s. So far, seems like the only time I have seen the 3422s is when you do just a prefix search on SIS, that seems to be the default nozzle it goes to for some reason.Pichu....the 3421 is a 7FB 400 nozzle, the 3423 is a 4MG 425 nozzle. The 3422 is 350....I think
The thin washer sets the nozzle tip closer to the piston, so the fuel hits the piston sooner....so called advanced timing. I have actually seen an improvement in power by taking the washers out. Not sure of the amount of timing advance, but it does work. Lowers EGT, and reduces smoke...to an extent.How can the thin washer advance timing? I understand it hits the bowl better with advanced timing but it should do nothing to timing of the injection.
:thinkingthanx!!sledman i believe that 3421,7fb was the LAST WILD nozzle and pumpeelout:bawl ,before EPA begins regulations, between a 400 7fb and 425 7fb there is no difference, the 25 hp to let it do air to air VS jacket cooler:sly unishPichu....the 3421 is a 7FB 400 nozzle, the 3423 is a 4MG 425 nozzle. The 3422 is 350....I think