OM617 nailing after injector service?
OM617 nailing after injector service?
04-16-2019, 09:05 PM
#1
Could it be a delivery valve or something? I'm an accomplished mechanic (I work on piston airplanes for a living), but am still learning about mechanical diesels. Any thoughts?
1990 Jeep Wrangler
'85 OM617.952/KKK K26/MW pump
OM617 turbo. Had some minor nailing and was preparing for a tune, so I decided to do an injector service. Had some slight "pissing" before pop on all five injectors. Brand new Bosch nozzles, all five injectors cleaned and lapped with a perfect, clean pop at 1850-1950 psi. Also reamed the glow plug holes at the same time. Got it all back together, and it runs GREAT. More power, better throttle response, easier starting, BUT even MORE nailing when cold, much louder, but goes away almost entirely when at full operating temperature.
Could it be a delivery valve or something? I'm an accomplished mechanic (I work on piston airplanes for a living), but am still learning about mechanical diesels. Any thoughts?
1990 Jeep Wrangler
'85 OM617.952/KKK K26/MW pump
04-17-2019, 12:07 AM
#2
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
The new nozzles do need to bed in a wee bit. Give it a few thousand miles and see what it does?
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
04-17-2019, 06:24 PM
#3
(04-17-2019, 12:07 AM)NZScott The new nozzles do need to bed in a wee bit. Give it a few thousand miles and see what it does?
I was kinda thinking that, especially since it gets so much better at operating temps. I've only probably put 40 miles on the nozzles so I'll just keep driving the thing!
1990 Jeep Wrangler
'85 OM617.952/KKK K26/MW pump
(04-17-2019, 12:07 AM)NZScott The new nozzles do need to bed in a wee bit. Give it a few thousand miles and see what it does?
I was kinda thinking that, especially since it gets so much better at operating temps. I've only probably put 40 miles on the nozzles so I'll just keep driving the thing!
1990 Jeep Wrangler
'85 OM617.952/KKK K26/MW pump
06-26-2019, 12:54 AM
#4
(04-16-2019, 09:05 PM)gregman_1 OM617 turbo. Had some minor nailing and was preparing for a tune, so I decided to do an injector service. Had some slight "pissing" before pop on all five injectors. Brand new Bosch nozzles, all five injectors cleaned and lapped with a perfect, clean pop at 1850-1950 psi. Also reamed the glow plug holes at the same time. Got it all back together, and it runs GREAT. More power, better throttle response, easier starting, BUT even MORE nailing when cold, much louder, but goes away almost entirely when at full operating temperature.
Could it be a delivery valve or something? I'm an accomplished mechanic (I work on piston airplanes for a living), but am still learning about mechanical diesels. Any thoughts?
Normal behavior of the engine and sounds like you did everything correctly.
Like already said, the nozzles need a few 1000 miles to settle. Very good nozzles like those Bosch (good atomisazion) still can be a little knocky after the settle period when the engine is still cold.
When the engine is warm and the knocking disappears, you are in the sweet spot.
But as you mentioned the power, response, better starting and less fuel consumption is something you want.
The nailing on a cold engine should also be much less or disappear with e.g. half throttle. If so, that is another sign for everything beeing correct.
Gruß
Volker
(04-16-2019, 09:05 PM)gregman_1 OM617 turbo. Had some minor nailing and was preparing for a tune, so I decided to do an injector service. Had some slight "pissing" before pop on all five injectors. Brand new Bosch nozzles, all five injectors cleaned and lapped with a perfect, clean pop at 1850-1950 psi. Also reamed the glow plug holes at the same time. Got it all back together, and it runs GREAT. More power, better throttle response, easier starting, BUT even MORE nailing when cold, much louder, but goes away almost entirely when at full operating temperature.
Could it be a delivery valve or something? I'm an accomplished mechanic (I work on piston airplanes for a living), but am still learning about mechanical diesels. Any thoughts?
Normal behavior of the engine and sounds like you did everything correctly.
Like already said, the nozzles need a few 1000 miles to settle. Very good nozzles like those Bosch (good atomisazion) still can be a little knocky after the settle period when the engine is still cold.
When the engine is warm and the knocking disappears, you are in the sweet spot.
But as you mentioned the power, response, better starting and less fuel consumption is something you want.
The nailing on a cold engine should also be much less or disappear with e.g. half throttle. If so, that is another sign for everything beeing correct.
Gruß
Volker
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