Which Injectors

[driverno8]

Tempting is an understatment. I've had mine back in about 3 days now. Power is extremely smooth. Just a tick more smokey. Nothing bad. EGTs are very manageble. Gained 40hp & 212lbs of tq on the dyno. Had to run my TST on 5/5 to make the most power. Before I had it on 7/7 to make the most. Just plain out of fuel. Modded CP3 here we come...

 

[KERMA]

Not a good idea to hone injector tips with a lot of miles on them, when there's lots of new injector tips available.

 

[RFahlen]

Not a good idea to hone injector tips with a lot of miles on them, when there's lots of new injector tips available.

What are you refering to?

 

[Van Blom]

Not a good idea to hone injector tips with a lot of miles on them, when there's lots of new injector tips available.

What would be wrong with honing old injectors?

 

[KERMA]

Honing injector tips that are already wore out won't make them new again.



Honing changes the spray holes and maybe the needle seat, but that stuff isn't what wears out first. Spray holes may plug etc but that is a symptom of another problem, it is not the cause. The part that wears is the OTHER END of the nozzle where the needle slides back and forth. This clearance is extremely critical and difficult to manufacture, but it profoundly affects the fuel return rates and pop pressure and ability of the nozzle to hold pressure. If the clearance is too large, like high miles nozzles, you won't develop pressure in the tip the same way. If it's too sloppy, like high miles nozzles, you are simply wasting your time and money trying to improve the spray holes. Nozzles with more than 50k miles ALWAYS show significant degradation in the return rates and pressure building/holding ability so IMO it's a waste of time to spend money honing something with too many miles.



Bosch nozzles are already fairly sloppy even when they are brand new from the factory, run some bad watery fuel through them and/or get them really hot with a fuel duration box and it makes matters worse. Maybe even crack the very tips of them with a pressure box, try fixing that with honing! Some slop is built into the fuel system to allow it to compensate for wear, neglect, marginal fuel, etc, but when you start pushing the cp-3 is when the differences start to show themselves.



Another thing- if your return rate is too high, you will drain the rail faster, because more fuel is being dumped past the injector being returned to the tank, without actually being injected into the cylionder to make power. Meaning: not as much peak power for the same CP-3 flow capacity. Some slop is allowed for in the design margins at stock power levels, so you the effect of wore out nozzles at stock or close to stock power is not as noticeable, but you may see the difference when you start challenging the CP-3 pump.



That's the trouble with using exchange injectors with someone else's used nozzles: you don't know if you are exchanging your low miles injectors for someone else's high miles injectors that are barely adequate in a "stock" application before they were modified. It is impossible to tell ouside the truck unless you have an injector test bench that tests the injectors at normal operating pressure. I don't think there are too many CP-3 test stands out there yet.

 

[RFahlen]

Honing injector tips that are already wore out won't make them new again.



Honing changes the spray holes and maybe the needle seat, but that stuff isn't what wears out first. Spray holes may plug etc but that is a symptom of another problem, it is not the cause. The part that wears is the OTHER END of the nozzle where the needle slides back and forth. This clearance is extremely critical and difficult to manufacture, but it profoundly affects the fuel return rates and pop pressure and ability of the nozzle to hold pressure. If the clearance is too large, like high miles nozzles, you won't develop pressure in the tip the same way. If it's too sloppy, like high miles nozzles, you are simply wasting your time and money trying to improve the spray holes. Nozzles with more than 50k miles ALWAYS show significant degradation in the return rates and pressure building/holding ability so IMO it's a waste of time to spend money honing something with too many miles.



Bosch nozzles are already fairly sloppy even when they are brand new from the factory, run some bad watery fuel through them and/or get them really hot with a fuel duration box and it makes matters worse. Maybe even crack the very tips of them with a pressure box, try fixing that with honing! Some slop is built into the fuel system to allow it to compensate for wear, neglect, marginal fuel, etc, but when you start pushing the cp-3 is when the differences start to show themselves.



Another thing- if your return rate is too high, you will drain the rail faster, because more fuel is being dumped past the injector being returned to the tank, without actually being injected into the cylionder to make power. Meaning: not as much peak power for the same CP-3 flow capacity. Some slop is allowed for in the design margins at stock power levels, so you the effect of wore out nozzles at stock or close to stock power is not as noticeable, but you may see the difference when you start challenging the CP-3 pump.



That's the trouble with using exchange injectors with someone else's used nozzles: you don't know if you are exchanging your low miles injectors for someone else's high miles injectors that are barely adequate in a "stock" application before they were modified. It is impossible to tell ouside the truck unless you have an injector test bench that tests the injectors at normal operating pressure. I don't think there are too many CP-3 test stands out there yet.

Quick everyone! Replace your 51,000 mile nozzles. Your truck is worn out. 03 and up trucks have 10 times more resistance to needle deflection than previous years. In your first paragraph you said yourself that machining needle tolerances is extremly difficult to do. Are you trying to tell everyone that there is a company that can do that better than Bosch? Please enlighten us. Who makes better nozzles than Bosch? I think we all know the answer to that question.





Ross

 

[Diesel Power]

good replie,it was much needed!! :-laf :-laf

 

[KERMA]

Readers digest version: Honing old nozzles won't make them new again.



Honing only enlarges the spray holes, it won't reduce or balance the return rates at all. If your injectors are already shot, honing won't help. That's all I'm saying. Maybe it's just too much detail.

 

[Diesel Power]

Readers digest version: Honing old nozzles won't make them new again.



Honing only enlarges the spray holes, it won't reduce or balance the return rates at all. If your injectors are already shot, honing won't help. That's all I'm saying. Maybe it's just too much detail.

true, if the body and internals are shot what good is a high flow tip???? Oo.

 

[betterthanstock]

Honing only enlarges the spray holes, it won't reduce or balance the return rates at all.

If that is the case, then replacing with your new nozzles will still not cure the problem, if the leakage is in the solenoid/body part of the injector.



Caterpillar extrude-hones their new injectors (after EDM) to balance flow and deburr the rough hole edges.

 

[KERMA]

New nozzles are honed before the aftermarket gets ahold of them- for instance Bosch calls it "hydro-grinding" but its the same thing. Nothing wrong with it, it works great for it's intended purpose! If the nozzles are in good condition, but it can't "unwear" old nozzles. Running abrasive juice through worn nozzles won't "heal" them.



The guy starting this thread has high miles on his injectors - he expressed concern about the high miles- and I personally don't think honing them is the right thing to do. It won't make them new again, no matter how good the honing is or who does it.



The parts are available to reman those injectors to better than new, and for sure that does not involve honing worn nozzles. Any reman will definitely involve new nozzles, which is most of the game if the rest of the injector is still functioning properly.