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+--- Thread: injection timing of MW on 617.952 (/showthread.php?tid=395)
injection timing of MW on 617.952 - Syncro_G - 05-31-2009
Hi, I just tried a search and didn't find any answers -
I'm wrapping up an engine overhaul, have new Monark injectors and re-set them to pop at 2100 psi (factory setting was at 1950 psi) I assume that will have a slighly retarding effect on injection timing. So next I want to set the pump timing a little advanced to compensate.
I have two questions:
First, am I thinking that out correctly?
Second, what's the proper way to test the pump timing? I'm following standard procedure as described by merc. source (turning crank slowly and looking for fuel to well up on the #1 injector). So when during the "well up" do you choose? The top of the hole is a cone (flare fitting) while in good light, I can see about a .5 mm or more further into the hole. While cranking slowly, I can see fuel start moving at the bottom of that hole at around 28-30 BTDC and about 5 degrees later, fuel is hitting the flare cone.
This seems like a pretty fuzzy way to set timing.
RE: injection timing of MW on 617.952 - GREASY_BEAST - 05-31-2009
I would vote yes you are thinking correctly, but the change might not be enough to notice. In any case, setting timing at 26°BTDC seems to work favorably for most people, and would probably cover any timing retard due to your extra 150psi.
As far as setting timing is concerned, just get a drip tube (or make one from an old injector line). That method is really accurate and you can get the timing set to within a degree or so.. just make sure you wire the "throttle" lever on full and remove the delivery valve in the #1 plunger before you attach the drip tube. It takes a little coordination to pump the primer pump and turn the engine over, its best done with a helper.
**By the way, the shop manual says start of delivery is indicated on the crank balancer when the drops from the drip tube have slowed to 1 drop/sec.**
RE: injection timing of MW on 617.952 - Syncro_G - 05-31-2009
(05-31-2009, 06:22 PM)GREASY_BEAST **By the way, the shop manual says start of delivery is indicated on the crank balancer when the drops from the drip tube have slowed to 1 drop/sec.**
I don't recall mention of wiring the throttle or a drip tube - I'll go back and read instructions again.
thanks.
RE: injection timing of MW on 617.952 - winmutt - 06-01-2009
Yes you have to be at WOT.