3B Rebuild and Performance Notes

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just bump the idle up a bit its a old 3b just the way they are with there old idi technology

my 3b idles at 600rpm which im fine with but if i even bump it up to 700 it smooths right out
 
Idle
Yes, you can bump it up at the throttle body, or bump it at the rear of the diaphragm housing since the vacuum pulls against that spring capsule at idle. you need a special socket (you can grind a 12mm to make one) to loosen the round nut to adjust the set screw. The truck will burn a tad more fuel at higher idle, and will carbon things faster in theory, but I have mine at 800 because my mounts are so hard it shakes th piss out of everything at 650.

I dissasembled all my old injectors today, and found 2 out of 4 had different nozzles in them.
#1 DN4SD24ND80- offshore/china, no branding logo
#2 ND-DN4SD24ND80- Genuine Denso, " D " logo
#3 ND-DN4SDND135- Genuine Denso, " D " logo
#4 ND-DN4SD24ND80-Geniune Denso, " D " logo

#1 had a very wide, fogged spray pattern/cone while the rest were a pretty tight cone with a condensed jet of fuel.
Oddly enough, #1 was the only one that "shrieked" when pumped hard. Shrieking is a tell tale sound that the nozzle is in good, useable shape. New ones are pretty loud.

So 4WheelAuto, or whoever they get to do their injectors, likes to take whatever is handy, and toss a set together. in their defense, the pressures were more or less spot on to stock spec...

I went through all the 3B nozzle numbers that toyota used through the years, and I had 2 out of 4. two are for the early till '82, 1 for '82-85.

The reamaining two available are:
DN4SD24- generic nozzle for H, L, J, and 3B. I have these in my rig now under Monark brand.
DN4SDND142- Last nozzle for the 3B 1988-on. Our supplier has a set of genuine DENSO, and my cost is peanuts, so Ill probably grab a set to measure and test.
Ill be measuring the orifice size on each that I have and I'll report back with what i find. In hindsight, I think the DN4SD24 might be better suited to a mildly boosted 3B, with really good MPG (Im gettting really good mileage, but a touch less power all round.) but not meant for high flow, I could be wrong though. The measurements between all 4 will tell the real story.

cheers
 
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Gerg, I'm leaning towards finding a set if merc nozzles that'll fit the holders with the same depth.
Or another route would be to extrude hone the stock nozzles and cut the pintle (very end that sticks out) back, or completely off. I've heard the merc guys speak of that.
My boss thinks I'm waisting my time, "its just a pintle"
but I've seen the videos of the idi mercs with hx30's rolling coal and doing rolling burnouts and the crazy acceleration... So I'm keepin the fire going... So to speak.

I'm going to try those 142 nozzles out and see what happens, I think I'll rebuild my spare set with them and sell the MONARK nozzles or as a complete set of injectors.

Its hard to say what the mileage is for sure since I haven't filled up yet. But I can tell you 25 bucks takes me a helluva lot further than it used to. There again, I had 3 different nozzles and a doubled up seat on #3, so anything would be better than that right? Ha. I was getting 11.5-12 l/100km on the highway previous to the rebuild.
I just put in 40L so I'll burn through that and let you know.
 
I guess it wasn't hard to improve upon the other set. The merc guys have unlocked quite a bit of power out of their pumps. Lots can be learned from them. I was joking about the dinner thing, but in a month or so I'm going through to Vernon and wouldn't mine checking out your truck and chatting you up if it works out. I'll PM you the dates when I know.
g
 
I've had some PMs about 3B injectors.
I'd like to keep a set ready to go for exchange, so you send me yours and you get a rebuilt set back with genuine nozzles of your choice, and your choice of opening pressure, stock+100psi, or custom. Price is $300 + shipping provided I get a set of cores in return.

I'd like to do this with 1HDT injectors as well, but since they are year and pump dependant, it makes it a bit more difficult

Cheers
 
Hows that 13bt pump working for ya?? I got a boost compensator and tried to have it fit up to my rotary pump but the tech said no dice. There is nothing to connect the compensator to in the pump. SO- I'm looking back at this thread to try to figure out which wat to go. Source a inline pump (if you still have yours I might need to take it off your hands) or go looking for a 13bt pump. What was it exactly that pushed you in that direction? It seemed like you had the 3b pump pretty well sorted.


P
 
apparently i lost my account (itwillmakeit?)but anyways
i found out the hard way that you don't play with the timing advance to much with 15-18lbs boost.
it cracks the crank :(
IMG_3675.webp
looks like a full rebuild now lol
 
Busted Crank said:
apparently i lost my account (itwillmakeit?)but anyways
i found out the hard way that you don't play with the timing advance to much with 15-18lbs boost.
it cracks the crank :(
View attachment 1026073
looks like a full rebuild now lol
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gerg said:
Ouch. I hear that. Mine went too with advance but I only ran it for about 10 seconds after it happened so only crank and bearings to replace for me, but that's enough of a job. Fortunately it stayed keyed together.
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Busted Crank: Sorry to hear about your broken crankshaft, hope the rebuild goes ok and nothing else is damaged.

You guys are scaring me, as I've been playing around with advanced timing a bit as well.

Busted Crank: How advanced was your timing? How rattly did your engine sound at idle? Can you provide a bit more info?

Gerg: What happened with yours? Were you going for more performance with advanced timing? Or did something go wrong and the timing suddenly advance on its own?

I'm pushing the limits on my little IDI 2.4 engine, and certainly don't want to end up with a broken crank also.
 
Gtssportcoupe mine didn't sound that rattly at all, no where near a di sound, as far as degrees I would assume 2-3 degrees over stock, but my 3b was a NA motor now with 15-18 lbs of boost with BAD cam bearings. Gergs motor went the same way as mine. Also the turbo version runs less advance so that should have been a hint to not advance the timing but oh well lol. I picked up a donor motor to rebuild, as the broken motor still runs so I can move my truck around the yard
 
Busted Crank said:
Gtssportcoupe mine didn't sound that rattly at all, no where near a di sound, as far as degrees I would assume 2-3 degrees over stock, but my 3b was a NA motor now with 15-18 lbs of boost with BAD cam bearings. Gergs motor went the same way as mine. Also the turbo version runs less advance so that should have been a hint to not advance the timing but oh well lol. I picked up a donor motor to rebuild, as the broken motor still runs so I can move my truck around the yard
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Thanks a lot for the info. Mine is definitely more rattly at idle. I'm not going to take any more chances though, and am going to return the timing back closer to stock. I am probably only advanced 1-2 degrees, and that is from the factory turbo spec. As my engine is electronic, I control this with a variable resistor, so easy to turn it back.

Glad you found another motor to rebuild. At least the 3B's are affordable and relatively plentiful these days as they trucks they were in reach a sad rusty demise.
 
When I get my 60 back on the road in a few months I will be retarding my timing lots. Maybe as much as 8-10 degrees as it wount have the intercooler and my IATs will be very high till I get it on again. How much is 8-10 degrees on a 3B pump with a rough line across there to tell you? I will be bringing it to a shop to get it set. Ive reduced the precup surface contact area so it should run hotter which will also speed ignition and flame propigation so timing will be affected there too. I definately will not be running cetane aditive which I was before when I did the timing advance. I too had no audible nailing or anyhting, but I did once for a short time when timing was very advanced and I managed to obliterate the tips of a full set of glow plugs. Now that was too much timing. Running lots of boost at low rpms again requires less timing as well. So I might decrease it a bit more and jsut run more boost to keep egts in check and see how the power goes. Ideally I should just spend a some time on a dyno and test different settings. Cource I have way too much time on my hands so thats high on the list.
 
gerg said:
Also, my coolant system was in great condition with a 4 core rad and I was still battling coolant temp issues when towing in the summer. In hind sight, too much advance makes sence with that. Should have been a giveaway.
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Funny thing is, mine seemed to be running cooler and more efficient with the advance. Takes longer to warm up as I'm driving to work in the morning. Counter intuitive, as I expected with earlier injection I'd have more burning happening in the pre-cups, and the head would be absorbing heat even faster. Could be that my engine was way too far retarded though. I think Toyota started doing this to reduce NOx emissions in the 90s vintage diesels, think it's the reason the 1hdt engines smoke at idle. My engine did too, until I advanced it.

Yeah, dyno would answer a lot of questions. We have one here at UVic; I should see if I can get some time on it by exchanging work or something.
 
GTSSportCoupe said:
Funny thing is, mine seemed to be running cooler and more efficient with the advance. Takes longer to warm up as I'm driving to work in the morning. Counter intuitive, as I expected with earlier injection I'd have more burning happening in the pre-cups, and the head would be absorbing heat even faster. Could be that my engine was way too far retarded though. I think Toyota started doing this to reduce NOx emissions in the 90s vintage diesels, think it's the reason the 1hdt engines smoke at idle. My engine did too, until I advanced it.

Yeah, dyno would answer a lot of questions. We have one here at UVic; I should see if I can get some time on it by exchanging work or something.
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Yes you will get cooler EGT and higher efficiency with more advance. Until you go too far.
But that comes with higher peak pressures and higher forces on everything. Hence broken cranks on high compression engines running more boost, more fuel and advanced timing.
 
GTSSportCoupe said:
Funny thing is, mine seemed to be running cooler and more efficient with the advance. Takes longer to warm up as I'm driving to work in the morning. Counter intuitive, as I expected with earlier injection I'd have more burning happening in the pre-cups, and the head would be absorbing heat even faster. Could be that my engine was way too far retarded though...
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So this is a dilemma. Setting timing for max fuel economy at part load, or setting timing for max safe power with a heat soaked engine bay with high intake temps at WOT in the summer when everything you can think of is as hot as it can possibly be. As your engine gets hotter, timing advances. So if your timing is already right on the edge at part load cruising to get a nice cup of timmies, your engine is basically killing it self that afternoon pulling the hills towing your RV. That is what I did to mine.
 
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