Injector Pop pressure: whats safe and what's not?
Injector Pop pressure: whats safe and what's not?
I understand that OE pop pressure for either of my engines (OM603 and the OM606 future swap) is 135bar(1950-2000psi) and that for big pumps and upgraded nozzles I've heard 150bar(2150-2200psi) is sort of the "gold-standard". Most notably for better spray/atomization when injecting more fuel in less time from a big pump. Most of what I've heard claimed relates to the difficulty of balancing the injectors with each other to a tight margin... it seems it gets harder and harder with higher pop pressure? BUT is there any actual dangers or simply diminishing returns and wasted effort? Reason I ask is because of current situation and lack of suitably sized nozzle shims.
Just bought a set of Firad SD 314 nozzles and a pop pressure tester to have a go at rebuilding injectors myself. All six injectors from the junkyard OM606 engine had poor spray patterns and leaked; what came out was SD 310 Bosch branded nozzles from France. While they did leak and spray poorly, the pop pressures for all of them were very close to 1950-2000ish psi.
After loading in the SD 314 Firad nozzles, pop pressure on the very first assembled injector dropped around 500psi to around 1400psi and was now opening even far below N/A spec of 1750. After adding the smallest shim I could find it bumped me up around 2800psi(190bar). After disassembling and sanding the shim down for a good bit; I ended up around 2600psi(180bar). How much further down do I need to bring pop pressures to be *safe* or can I give it a whirl like this assuming they will break-in and drop in pressure?
If anyone has a good lead on a suitable shim kit for these injectors, I'm actually in a position to where I'd purchase a decent quantity (not that BS kit on merc source that only has 26 and is over $40) as I've got several sets of injectors I'd like to rebuild. If 2600psi is a safe pressure though to where I won't cause damage then I'd like to try it just to see the difference if any. I understand it'll retard timing to a degree but it sort of nails at 8 degrees anyways so maybe it'll quiet/smooth it down some.
TwoMuchBoost
02-26-2020, 04:28 PM #1My only real concern is not causing damage to my dieselmeken pump w/ 7.5mm elements.
I understand that OE pop pressure for either of my engines (OM603 and the OM606 future swap) is 135bar(1950-2000psi) and that for big pumps and upgraded nozzles I've heard 150bar(2150-2200psi) is sort of the "gold-standard". Most notably for better spray/atomization when injecting more fuel in less time from a big pump. Most of what I've heard claimed relates to the difficulty of balancing the injectors with each other to a tight margin... it seems it gets harder and harder with higher pop pressure? BUT is there any actual dangers or simply diminishing returns and wasted effort? Reason I ask is because of current situation and lack of suitably sized nozzle shims.
Just bought a set of Firad SD 314 nozzles and a pop pressure tester to have a go at rebuilding injectors myself. All six injectors from the junkyard OM606 engine had poor spray patterns and leaked; what came out was SD 310 Bosch branded nozzles from France. While they did leak and spray poorly, the pop pressures for all of them were very close to 1950-2000ish psi.
After loading in the SD 314 Firad nozzles, pop pressure on the very first assembled injector dropped around 500psi to around 1400psi and was now opening even far below N/A spec of 1750. After adding the smallest shim I could find it bumped me up around 2800psi(190bar). After disassembling and sanding the shim down for a good bit; I ended up around 2600psi(180bar). How much further down do I need to bring pop pressures to be *safe* or can I give it a whirl like this assuming they will break-in and drop in pressure?
If anyone has a good lead on a suitable shim kit for these injectors, I'm actually in a position to where I'd purchase a decent quantity (not that BS kit on merc source that only has 26 and is over $40) as I've got several sets of injectors I'd like to rebuild. If 2600psi is a safe pressure though to where I won't cause damage then I'd like to try it just to see the difference if any. I understand it'll retard timing to a degree but it sort of nails at 8 degrees anyways so maybe it'll quiet/smooth it down some.
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