My oil pump drive unit has stopped working because it froze up and will not spin anymore. I have new one that I would like to install but I don't have any reference marks to go by. Since the old one stop spinning. After I bring #1 cyl to TDC how can be sure it's going to be timed correctly?

 

This is how I would do it

Set engine to #1 TDC, remove Distributor,

Install new oil pump,

Reinstall distributor With the tip of the rotor pointed to the #1 sparkplug wire.

If it doesnt drop right in line up the oil pump drive spindle by putting a long flathead screw driver through the distro hole in the block and turn the spindle to the correct location.

Hope that helps,
Matt

PS if you do as i told you and it doesnt start when you finish then you have the distributor 180 out remove it and spin the rotor 180 degrees. then reinstall

 

Thanks for your response,

Your method seems great but my system is the distributor less ignition so I have a camshaft position sensor on top of my distributor and no spark plug wires but the coil packs that set on top of the engine. Therefore I cannot align the rotor tip pointed at #1 and I have the 4.0 motor.

 

When you put #1 piston in TDC be sure it is in fireing stroke (both valves closed) and not in exhaust stroke (exhaust valve open).