Lavoy wrote: When at TDC, and the marks lined up in the pump, is that zero degrees advance for lack of a better term? I would think you would want a few degrees advance.
Lavoy
It doesn't work that way. Without a book full of specs, you have no idea what those marks mean. The plate that has the mark on it (the half that rotates) is hand-installed and differs by pump number.
For example, 1010 diesels have two different pumps.
Pump # 1 is DBGVC429-1DH (Deere # AT16517).
The timing mark is put onto the part, while laid on a degree wheel - at 48.5 pump degrees.
Pump # 2 is DBGVC429-1J (Deere # AT12457).
The timing mark is put onto the part, while laid on a deree wheel - at 50.5 pump degrees.
Pump # 3 is DBGVC429-3AJ (Deere # AT14849)
The timing mark is put onto the part, while laid on a deree wheel - at 47.5 pump degrees.
So, right there, there's two-degree timing difference between the three 1010 pumps when the lines are lined up - and two pump-degrees = four engine degrees. So, just from one model pump to the other, there's a four degree difference in initial timing with those damn lines, lined up.
Remember a pump only runs at half engine speed, so 1 pump degree = 2 engine degrees, and 1000 pump RPM = 2000 engine RPM.
That's why I was suggesting you just move the pump a bit and try it. It can get confusing - mainly because it is.
Those three pumps have other differences to make things more confusing.
Pump # 1 , DBGVC429-1DH (Deere # AT16517), has an automatic timing advance that works like this. 1 pump degree at 350 pump RPM. 6 pump degrees at 1000 pump RPM, and 8 pump degree total advance (which is 16 engine degrees).
Pump # 2 , DBGVC429-1J (Deere # AT12457) has less advance movement. It moves 2 pump degrees by 350 pump RPM, and a total advance movement of only 4 pump degrees.
Pump # 3, DBGVC429-3AJ (Deere # AT14849). 1 pump degree at 375 pump RPM, 5 pump degrees at 1000 pump RPM, and 7 pump degrees total by 1325 pump RPM.
So, from one pump to the other, there are major differences in initial timing as well as total advance. Also a difference in fuel delivery.
One pumps more fuel and less timing advance, and the other the converse.
The early 1J pump has load-advance only. The later 1DH and 3AJ pumps have speed-advance.
I hate to say it, but for these reasons you're better off timing the thing by ear. Deere was never sure what worked best, the 1010 was a work in progress - that ceased production before it was all figured out.
I have a British International Harvester B275 diesel tractor, the same year as my 1960 1010 - and the Brits make tuning much easier. My repair manual states - for more power - advance the timing until the engine gets noisy if more power is desired. If less noise is desired, retard timing, but less power and poorer cold starting will result.