Diesel tech

SVcummins · Mar 21, 2019

I pulled an injection pump off a 4020 one time and
had it went through and turned up and some other
work done to it I wanted them to retime the pump for
whatever reason I can?t remember what it was the
timing marks weren?t lined up. Well when I got the
pump back the marks still weren?t lined up so I
called and they said just turn the shaft so the marks
line up and put it on I set the engine on tdc number
1 lined the pump marks up put it together and it
worked fine ever since how can that be

Dieseltech · Mar 21, 2019

Depending on the pump model, the internal weight retainer mark is at 126, 127, or 128 degrees on the setting plate tool. This mark is for end of injection, but on the spec sheet it actual true end of injection is a bit earlier. If I recall there are at least two different tang drive shafts used, and did see some incorrectly marked shafts years ago when comparing the drive end angles with pump end clamped in a vise. So my guess would be weight retainer was replaced with a timing mark change and/or drive shaft change. On the 4020 build time there are several pump changes, Synchro and Power shift used different max fuel settings, DB housings on early engines and JDB housings on late blocks. Weight retainers and governor weights, advance range is different on later models also.

SVcummins · Mar 27, 2019

That all makes sense . But shouldn?t a pump have to be timed so the marks would be lined up before it would run? When I asked the pump shop what to do they asked well is the pump lock timed ? I said no they said well then you can just turn the shaft the timing mark indict the pump lines up with the mark on the pump housing and it will work well that?s what I did and it worked

Diesel tech

SVcummins

Well-known Member

Dieseltech

Well-known Member

SVcummins

Well-known Member

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