If I understand correctly, TDC is ordinarily found by aligning the timing mark from the crank pulley. However, if I'm seeing it right, the "mark" is actually notched into the plate which is mounted on the back side of the pulley itself. Assuming I'm correct, this is the beginning of my problem. You see, the plate on the back side of my pulley came detached (I think it was previously on a rubber dampening ring which wore away??) so I now cannot be confident of it's position (we tack welded it back onto the pulley itself.) Is there an alternate way to determine TDC? For example, on my old BMW I can look at the upper timing chain pulley as a reference. Is there something comparable on an '80 280zx that I can use for a reference point and then make a new mark on the crank pulley? Thanks in advance.

 

if my memory hasn't failed completely there is a mark on the camshaft end that references to a mark on the head. alternately you can find it by putting a stick in the plug hole and jacking the engine back and forth when both lobes of the cam for #1 cylinder are pointing up and out. when the stick no longer moves up or down that is TDC.

 

EDIT... Roger beat me to it.

There are several ways. All are mentioned in the FSM (I always mention the FSM because it's a lot easier to find the info there, rather than wait for someone to respond on the forums ).

Since it's a 4 cycle, piston 1 will be at TDC twice. You need to find the compression stroke where the valves are closed. To do so, you can rotate the block and set the distributor rotor to cyl #1, then check through the spark plug hole that the piston is at the top. If you can see the crank bolt, then you can align the woodruff key notch to the TDC location. You can also open the valve cover and rotate until cyl #1 cam lobes are both up & distrib rotor is at #1.

 

Thanks guys. Aligning the #1 cam lobes and distributor rotor seems like a logical approach. I can't quite get my head around the stick trick you are mentioning. I also had looked in the FRS on Zenon's site but honestly find it challenging to search, and could not locate the timing section in any of the logical places. Weird.

 

The #1 cam lobes will look like floppy bunny ears and the dizzy rotor will point to #1.