pump timing

[1340]

Correct me if I'm wrong but I understand that the fuel pump timing can be advanced by turning the pump until the lines on the pump and gear case are about 1/16" apart. Is there a more accurate method? Thanks.

 

[dpuckett]

Yes, there is, the one recommended by the "book. " Involves a dial indicator, adaptor, and finding TRUE Top Dead Center, not just relying on the timing pin. Contrary to popular belief, you can use an SAE dial indicator, just takes some converting from MM to thousandths of an inch. (25. 4mm to the inch). Do a search on timing in the 1st Gen forum, and you should be abel to find what you need. Or just follow the book, and not rely on the timing pin for true TDC, only as a guide to get you in the general area.



However, moving the timng up a bit can get you an increase in fuel efficiency, bottom end take off, and cut smoke. To each his own. I've done it both ways, and can tell you it is possible to go WAY over on the timing and not know it.



Daniel

 

[tugboatphil]

Daniel,



Will going too far bring the idle up to a point where it can't be brought down with the idle screw? My idle screw doesn't even touch and it still runs about 900-1000 (using my ear).

 

[Greenleaf]

If memory serves.......

Advancing the timing will increase idle speed.

Performance injectors will decrease the idle speed.

Turning up the pump's full fuel screw will increrase the idle speed.



-S

 

[dpuckett]

You have to go quite a ways to get the idle up more than a hair with timing alone.

Turning the full power screw will increase idle.

Injectors can increase or decrease idle speed, depending on flow and pop pressure. Higher pop off will retard dynamic timing, and possibly lower idle.

tugboatphil- how long is your throttle rod? If the throttle lever on the pump isnt even touching the screw, there is something keeping it from going back to idle. Try lengthening the throttle rod and see if you can lower your idle that way. It works like a turnbuckle- turn one way to lengthen, the other way to shorten. Retighten the 10mm nuts and go.



Daniel