Timing for a JD1010 4 cylinder gas engine

[Mariner]

HI,

I am trying to get the right values for the gas engine in a JD1010 farm tractor - I assume the engines are the same as for the crawler loaders/bulldozers etc.

So far I have : points at 0.022"
plugs at 0.025"

I still need the timing for the distributor - I am guessing at 6 degrees BTDC

Could someone please confirm this value for me please.

Thank you

mariner

[Pammark]

There are a few rules-of-thumb that will work. The time when the points just open is when the spark will occur. The magentic field in the coil collapses when the circuit opens and this induces the high voltage to the rotor and plugs.

Set the engine at TDC and rotate the distributor until the points just start to open. Tighten down. Now start the egnie and it will run. You can use a timing light or just listen to the engine to get a better timing. With a timing light, make sure you idle the engine down about as low of RPM's that it will still run. This will make sure the centrifugal advance is not working. Also disconnect any vacuum lines for the advance (if any) and plug. Now set the timing about 5-6 degrees BTDC.

If the engine pings under load (assuming you do not have cheap gas), it is almost perfect timing. Retard the timing just a little until the pinging stops.

Gasoline takes time to burn. That is why the timing is BTDC, so when the burn complets its time, the engine is at TDC for full power. If the timing is too early, the pinging is the engine trying to run backwards (too early). If the timing is too retarded, there will be lost power and probably the engine will be run hotter.


Mark

[ritchiegilby]

yes those settings are accurate ot least for my 1010 crawler 4 cyl gas 1965