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  #1  
Old 03-22-2007, 10:07 PM
henrydupont
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so, what does that rack damper bolt (617) actually do?

does it do more than simply adjust idle? what 'rack' does it adjust? how to make a 617 not shake at idle? is it possible??
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Old 03-22-2007, 11:27 PM
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It dampens the rack.
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Old 03-22-2007, 11:36 PM
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My best guess is that the rack is something inside the injection pump that controls how much fuel is injected, by dampening it, it cancels out the vibration of the engine from creating a resonating injection of fuel that makes the vibration worse, someone pleasr correct me if i'm wrong...
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Old 03-22-2007, 11:38 PM
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As far as I understand that is correct.

I'm sure somebody who has commited the Bosch manual to memory will chime in soon.
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  #5  
Old 03-23-2007, 09:11 AM
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Was ist der rack?

I to - as a newbie - have wondered what the rack actually is. I asked the same question a while back and never got a posting that explained what the rack in the IP does.

There are lots of postings on how to adjust it, nothing on what you are actually changing by adjusting said bolt.

My engine doesn't vibrate a lot at idle (certainly compared to the tractor ) so I have never bothered to mess with it.

Last edited by 300sdToronto; 03-23-2007 at 09:13 AM. Reason: typo
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Old 03-23-2007, 02:26 PM
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Sorry I couldn't find a photo but here goes..........o o o o o.(the o's=valves & underline=rack)............The rack is a geared shaft in the IP that turns a tapered plunger in the fuel delivery valve to control the amount of fuel delivered with each stroke. When the rack returns to idle, the dampner cushions the return for a more gradual decrease at the very end of its travel.
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Old 03-23-2007, 03:35 PM
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Quote:
Originally Posted by SD Blue View Post
Sorry I couldn't find a photo but here goes..........o o o o o.(the o's=valves & underline=rack)............The rack is a geared shaft in the IP that turns a tapered plunger in the fuel delivery valve to control the amount of fuel delivered with each stroke. When the rack returns to idle, the dampner cushions the return for a more gradual decrease at the very end of its travel.
Yes that concept is correct and let me add on each plunger there is a groove in which allows fuel to leak out to the bleed holes to limit the pressure. The "control" rack turns the plunger so the grooves can meet up with the bleed hole.

Here is the pics that your looking for.
Attached Thumbnails
so, what does that rack damper bolt (617) actually do?-boschinjector-cutaway.jpg   so, what does that rack damper bolt (617) actually do?-boschplunger-cutaway.jpg  
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  #8  
Old 03-23-2007, 03:40 PM
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I have an IP completely dissasembled and that rack itself is pretty cool
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  #9  
Old 03-23-2007, 07:45 PM
henrydupont
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truly great information there. so when I adjust the rack damper I'm not adjusting idle speed, just idle shakyness? what adjusts idle speed then?
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  #10  
Old 03-23-2007, 07:47 PM
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There's an idle adjusting screw on the IP on the block side. It has a slotted head and a lock nut.
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  #11  
Old 03-24-2007, 03:27 PM
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Quote:
Originally Posted by bgkast View Post
It dampens the rack.
why would we want to "dampen" any "rack"? lol lol
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Old 03-25-2007, 10:55 PM
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Here is a picture of the old silver damper and the new gold damper. (The blue lines in the picture are camera artifacts).
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so, what does that rack damper bolt (617) actually do?-rack-damper-gold-silver.jpg  
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  #13  
Old 01-04-2010, 08:21 PM
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I do not know exactly what the rack dampner does...
but I know the MB engineers designed it so that future wear ( excess play ) could be ' taken out' by adjusting it..
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Old 04-04-2015, 04:56 AM
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Recycled

For new members.
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