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Injector Nozzle Swap


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I believe the tip torque is 35 ft-lb 

Injector hold down are 89 in-lb

Really simple process. Just make sure you keep everything clean! Why'd you pick up another set of injectors? I would use the ones you have in there if you know the pop off pressures are correct. 

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I believe the tip torque is 35 ft-lb 

Injector hold down are 89 in-lb

Really simple process. Just make sure you keep everything clean! Why'd you pick up another set of injectors? I would use the ones you have in there if you know the pop off pressures are correct. 

For $50 it's worth having another set of injectors kickin around. Now I can sell my 60s, put huge nozzles on them or keep them as back ups.

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Once your done changing nozzles now you got to send all six injectors out and and have them pop tested. You can't just change nozzles without having them re-pop tested. Usually make nozzle sets higher in price once you figure in pop testing and tuning. Locally its $15 a injector to be tuned.

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How do injector tips effect the pop pressure??

 

From small changes is length of the pintle needle and/or seat depth. Maybe the owners shims are already worn too. That why there is different sized shims for tuning the pop pressure so that all injectors are evenly match in pressures. It's always being suggest in pop testing all injectors after nozzle install.

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Like I learned from the RV275's I got from CajFlynn. Just because they all popped about 290-295 bar (little low) still good to go. By the next year they had dropped off to 240 bar on the lowest injector. When they where inspection in Lewiston, ID there was shims that where wore down, pintles where seated deeper in the nozzle from wear. So now between the shim wear and the nozzle wear will give that slack for change in pop pressure. Now even with new nozzles if the shims are worn your still going to be off in pressure. So more or less you got a fresh tip but the rest of it worn and might not match perfectly (305-310 bar).

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Like I learned from the RV275's I got from CajFlynn. Just because they all popped about 290-295 bar (little low) still good to go. By the next year they had dropped off to 240 bar on the lowest injector. When they where inspection in Lewiston, ID there was shims that where wore down, pintles where seated deeper in the nozzle from wear. So now between the shim wear and the nozzle wear will give that slack for change in pop pressure. Now even with new nozzles if the shims are worn your still going to be off in pressure. So more or less you got a fresh tip but the rest of it worn and might not match perfectly (305-310 bar).

DDP recommends the pop off pressure to be 290 bar and I've seen it like you said at 310, is there a set factory pressure? Should high performance injectors be set higher?

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Here is Dodge FSM specs.

fuel-pressure-specs.jpg

 

The only thing you gain by lower pop pressure is timing and spray quality degrades as pressure is reduced. Also sooner the boost pressure can flood the fuel system on a deceleration. Just like tractor pullers they get to the end of the track and gotta tap the throttle a few time to keep if from dying out. This is to push the air bubbles back out of the injectors. Higher the pressure the later in timing but better the quality of the spray and atomization equals better efficiency.

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Once your done changing nozzles now you got to send all six injectors out and and have them pop tested. You can't just change nozzles without having them re-pop tested. Usually make nozzle sets higher in price once you figure in pop testing and tuning. Locally its $15 a injector to be tuned.

 

Mike you were right, as usual, nozzles alone with testing would be more expensive so I just ordered 100 hp injectors for $350, maybe it was $380 with cross over tube rings.  

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Just to reiterate, torque the hold down bolt to 89 in-lbs, then push the cross over tube in and tighten the injector line? I think last time I pushed the tube in, then torqued the hold down bolt to spec...

 

Backwards.

 

1. Push the injector in.

2. Now push in your crossover tube.

3. Pre-torque the crossover tube.

4. Torque the injector cap. (89 in/lbs)

5. Finish tightening the cross over tubes.

 

This allows the crossover tubes to push the injector where it needs to to center up for proper seal of the crossover tube.

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