B vs 3B injector interchangeability?

[bblawless]

Hey everyone. I’ve got a 79 bj40 with a B motor in it. Turbo’d it last year, which was a great improvement but I expect it’s time for my injectors to be replaced. I can’t seem to find many options for “B” injectors online, but lots for the 3b. Are they interchangeable?

On another note- I’d love to manage to lower my egts while maintaining higher boost/fueling. Has anyone on here done a intercooling setup? I was looking into water to air systems…little intriguing.

Thanks guys!

 

[bj70bc]

yes, ive water to air intercooled my turboed 3b

 

[bblawless]

yes, ive water to air intercooled my turboed 3b

Would you happen to have any photos of your setup?

 

[bj70bc]

this is the intercooler core i used and are more efficient than the barrel type, for the heat exchanger i used a 12x12x2"thick rad style unit, and a 2 gallon reservoir.

intercooler core is mounted vertically

pipe comes back up from the cooler to the intake, with recirculating bov

 

[bj70bc]

piping is a bit of a clusterfaulk and could be run a bit better, but this is how it is staying

 

[bj70bc]

3b timing should be slightly retarded and the turbo ran with enough boost vs fuel to keep the egt's heat as low as possible
And you are right on the injectors, if they arent popping at the right pressures, leaking, poor atomization etc, they can contribute to improper timed injection and therefore contributing too high peak cylinder pressures and too much pressure on the crank

 

[iliketrucks]

How much boost are you running? My thought process is safe boost levels on an IDI B series are single digits (<10 PSI) and at that level the air isn't compressed/hot enough to benefit from an intercooler. Just my understanding.

 

[duncanrm]

There was a few versions of the 3B engine including one with a rotary injection pump that had different crack pressures etc. Injectors can easily be rebuilt, there's no need to "replace".. find a good local diesel shop and have yours rebuilt,

 

[bj70bc]

yes rebuild them

How much boost are you running? My thought process is safe boost levels on an IDI B series are single digits (<10 PSI) and at that level the air isn't compressed/hot enough to benefit from an intercooler. Just my understanding.

there are three thoughts on this
1-never turbo a idi engine as they run too high compression from the get go and will shed too much heat into the head from the pre cups
2-no intercooler, run low boost to keep things under control, (less than 12 psi) but then people turn up the fuel and a rich burn is very bad for these engines
3-run as much boost as keeps the egt's down, and use intercooler to take the heat of air compression out of the intake charge, (12+psi)

I found (for me) an intercooled 18psi is where the amount of air entering the burn was cooling the egt's enough to run safely, and my fuel setting did not get turned up very much at all, very conservative fuel setting, and slightly retarded fuel timing with slightly higher injector pop pressure, all of which contributes to keeping peak cylinder pressures on the safe side for the crank and heat load on the engine safe

 

[bblawless]

3b timing should be slightly retarded and the turbo ran with enough boost vs fuel to keep the egt's heat as low as possible
And you are right on the injectors, if they arent popping at the right pressures, leaking, poor atomization etc, they can contribute to improper timed injection and therefore contributing too high peak cylinder pressures and too much pressure on the crank

I’m sorry, are you suggesting I also need to retard my timing? Like after the turbo installation?

 

[bblawless]

How much boost are you running? My thought process is safe boost levels on an IDI B series are single digits (<10 PSI) and at that level the air isn't compressed/hot enough to benefit from an intercooler. Just my understanding.

I’ve gone up and down playing with the fuel delivery. Currently, it peaks around 12-13psi. I’ve had it as high as 18, but temps were way too high and I figured that kind of boost was a little reckless. I’m mostly trying to get my egts down so I don’t need to watch them like a hawk while I’m on the highway. I’m on Vancouver island, our highways are very “hilly”.

As far as the injectors go, judging by the above information I’ll likely just take them to a reputable local shop to have them rebuilt instead of replacing the entire body.

Thanks for all the input guys

 

[bj70bc]

I’m sorry, are you suggesting I also need to retard my timing? Like after the turbo installation?

Timing on turboed engines will be retarded a bit from what it runs as a N/A engine, turbo heat and pressure speed up the combustion in the cylinder, if you want to be a bit nicer to the engine internals retarding your timing a bit is a good thing to do. there are timing marks on the injection pump and you can loosen the bolts and rotate the pump (away from the engine block) to retard timing, the timing marks are pretty crude tho and how much to move it is a complete guess, consensus says no more than a 1mm from the current position. This is where mine has been moved to and i had to cut the lead locking metal wire twists to do this (if i remember correctly) so mine was 'as-set' from the factory. There is also a rpm dependent auto timing advance device on the end of the timing gear behind the timing case, some people have messed with this, i havent. Ideally one would adjust this auto timing advance to compensate for the turbo doing this to some degree as well.

You also said you were getting too much heat running more boost, have you tried adjusting the wastegate with a boost controller, heavier wastegate spring, bleed valve, or by wiring the wastegate closed to get more boost or are you just using fuel to increase your boost? more air with less fuel is the safe way to go
Whether you do these things is up to you, but a haphazard turbo install on a 3b rarely goes well, even at the 10-12psi range

Also, if you are on the original composite headgasket you are on borrowed time, it needs to be changed to a toyota mls gasket, for sure. And while you are in there you will have cracked precups, they need to done too so you dont drop a precup and sieze your engine.

 

[bj70bc]

i know i know.... ignorance was bliss
now you know, and knowings half the battle... G.I. JOE!