4020 diesel injector pump timing

cliffswan · Apr 18, 2023

Just rebuilt the engine on a JD4020 with the Roosa pump. Tractor starts and seems to run well once it starts, but it takes an excessive amount of cranking before it does start. Removed the rectangular cover over the timing marks view port and the two lines are offset about 1/8 of an inch with engine off.
Is that enough to cause a hard starting issue?
I can't seem to rotate the pump enough to get the lines to match up. Too much tension on all the steel high pressure steel lines between pump and injectors. Any hints on how to overcome this tension? These lines were bent during removal and it took a lot of struggling to get everything connected without crossthreading anything. (Did I mention that I hate steel lines).

Thanks for any insights
Cliff Swan

Muir hill 101 · Apr 19, 2023

Yes line the lines as perfectly as you can . Those steel
lines can be a bit of an sob thats for sure

tomstractorsandtoys · Apr 19, 2023

Sometimes you have to use a big pair of channel lock pliers to twist the pump. Tom

rustred · Apr 19, 2023

there should be slots in the drive gear to give u more adjustment. dont be forcing them lines. 1/8 inch off is way out of time!get a manual
to see the procedure on this.

wore out · Apr 19, 2023

(quoted from post at 09:32:03 04/19/23) there should be slots in the drive gear to give u more adjustment. dont be forcing them lines. 1/8 inch off is way out of time!get a manual
to see the procedure on this.

4020 injection pump is driven by an offset slot coupler from the oil pump shaft.

NO slotted gear involved, the only way to change the slot position is to drop the oil pump and advance or retard it by one gear tooth which s a BIG change.

Muir hill 101 · Apr 19, 2023

Loosen the lines so the pump can turn

EP · Apr 20, 2023

Couple things, is there a bunch of play in
the gears driving the pump. The cam gear and
or oil pump gear can get very worn out
causing timing issues. Second if the pump
hasn't had a seal kit installed, the governor
ring could be shot, also causing timing
trouble.

cliffswan · Apr 29, 2023

Thanks all you guys for your suggestions.

As per one of the replies I loosened all the lines thus
allowing me to turn pump enough to line marks perfectly.

Tractor now starts within a few revolutions and seems to
run well.
That 1/8inch misalignment of the timing marks certainly
increased starting difficulties.

4020 diesel injector pump timing

cliffswan

New User

Muir hill 101

Member

tomstractorsandtoys

Well-known Member

rustred

Well-known Member

wore out

Well-known Member

Muir hill 101

Member

EP

Member

cliffswan

New User

Similar threads