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68gmsee · 08-20-2010, 10:41 PM

You seem to have done everything correctly. It shouldn't be too much trouble to recheck the timing though.

You did it the way I do mine also. I remove the plug stick my finger or thumb until I start to feel pressure then finish with a long thin plastic or wooden dowl I feel the piston as it reaches the top. On the 250 you should be able to see it.

If it is all correct and lined up like the first time you checked, then make sure you unplug the vacuum advance line and plug it up. Also make sure there aren't any other vacuum leaks. If it's till off like you mentioned, make sure your distributor mechanical advance is working correctly.

After that, I don't know unless you have some mechanical problems like extremely worn cam/crank gears or dist gears.

08-20-2010, 10:41 PM	#5
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: setting timing in 68 c-10 with 250 You seem to have done everything correctly. It shouldn't be too much trouble to recheck the timing though. You did it the way I do mine also. I remove the plug stick my finger or thumb until I start to feel pressure then finish with a long thin plastic or wooden dowl I feel the piston as it reaches the top. On the 250 you should be able to see it. If it is all correct and lined up like the first time you checked, then make sure you unplug the vacuum advance line and plug it up. Also make sure there aren't any other vacuum leaks. If it's till off like you mentioned, make sure your distributor mechanical advance is working correctly. After that, I don't know unless you have some mechanical problems like extremely worn cam/crank gears or dist gears. Last edited by 68gmsee; 08-20-2010 at 10:42 PM.