I have attempted to adjust the timing on my 86 Iron Duke as she runs very rich. I adjusted according to the marks on the pulley...it got a little better but I have a feeling the marks are incorrect. How do I find TDC? And how do I know if the distributor is positioned right? I need to make sure I have the marks in the right place before I attempt to time it this time around.

Thanks,
Craig

There's a tool you put in your #1 spark plug hole, rotate the crankshaft until it contacts the tool, and mark it. Rotate other direction, when it contacts, mark it. Halfway between the marks is TDC. Not sure how much the tool is, but it's probably about $5. Hope this helps,

Do you know what the tool is called? Can I pick this up at a Discount Auto Parts, NAPA, or other retail parts shop?

Craig

You need a dial indicator that measures to the nearest .001", these are not $5 and you could use several diffent types, depending on how you are going to measure. I would use the height gauge type that has a drop rod. You also need a magnetic base to attach it to your engine block or head. You would place the measuring part of the instrument or a rod into the spark plug opening and rotate the engine by hand, do not use the starter motor for this. You would measure the number one piston's upwards travel to it highest point, mark your harmonic balancer pulley where it matches the zero degree timing mark. Rotate the engine in the opposite direction and do the same. Halfway between the marks you made would be your actual zero position and this should be your final correct timing mark. You can either paint this mark on the harmonic balancer or have it engraved/milled on.

Yep. You can go with the $5 tool, or do what av said above. Both will get you there. Not sure what it's called. Top dead center indexer? Go to your local parts shop and ask them. If they're not 10 year olds, they should know.

LOL I'm going to check this weekend...I'll let you know whats its called.

Craig

Did you have diagnostic terminal on ALDL grounded? If not your timing will be incorrect. Ground terminal to set timing at base value (no ECM control).

You can see/feel #1 intake valve rocker arm through the oil fill cap hole. Useful to reference #1 coming up on compression stroke when turning the engine by hand.