By popular demand!
Here is a way to check for Top Dead Center with the cylinder head still on the engine (you may be surprised how far the mark on the crank pulley can be off on a 2.3, or any other engine) This is the procedure I used on my 2.3 engine that's in my 88 ranger.
Step 1: Making the TDC checking tool.
Take an old spark plug, (please wear eye protection while making this TDC tool) break off the porcelain on the top of the plug all the way down to the main body of the plug. Right above the hex the plug body is rolled over to hold the porcelain into the body of the plug take a cut off wheel and or grind the rolled over portion of the plug body down also grind off the electrode off the plug body, clamp the plug body upside down at the hex in a vice (no too tight so you don't distort the plug body, take a punch about 5/16th" in dia and knock the rest of the porcelain through the plug body, put a 5/16th"x2" long bolt put it through the plug body then put a crimp style lock nut to secure the bolt into the plug body then grind the edges of the nut off so that it doesn't interfere with the threads in the cylinder head.
The completed TDC checking tool.
Step 2: Checking for TDC using your new TDC checking tool.
If you are replacing a broken timing belt, before you remove the front cover and broken timing belt, take out the number one spark plug, with a flash light look into the plug hole to check and see if the piston is near TDC (if it's close you will see the top of the piston in the plug hole) if you see the piston top rotate the crank shaft about a quarter turn or so, you shouldn't be able to see the piston through the plug hole after you have done that, now insert the TDC checking tool into the plug hole just like you would a regular spark plug.
TDC checking tool installed in the number one cylinder in my 2.3 in my 88 ranger.
Step 3: Verifying TDC.
Slowly (gently) rotate the crankshaft counter-clockwise (remove the rest of the spark plugs before you do this, the crankshaft will be alot easier to turn) keep turning the crankshaft until it stops, using a marker of some kind mark the pulley at where the TDC mark is on the front cover (I used tape), now rotate the crankshaft clockwise as you did before until it stops, now mark the pulley again where the TDC mark is on the front cover, now turn the crankshaft back a little and remove the TDC checking tool. Now measure the distance between the two marks you made and find the center and mark the pulley (I used a scribe then took a chisel to make the new TDC mark).
Now looking at the picture, to the left of the new TDC mark I made (between the two pieces of tape you can see the factory TDC mark is off by about 4 degree's).
This also can be done with the timing belt on (but be careful, it is possible for the exhaust valve to hit the TDC checking tool while rotating the engine) You can do this safely by making sure that the piston is just low enough so you don't see it in the plug hole, and you can also see if the exhaust valve close to the plug hole is opening or closing while checking the piston, install the TDC checking tool and carefully rotate the engine either by hand or the proper size socket with a ratchet until it stops (it shouldn't have to turn much), now remove the TDC checking tool then turn the crankshaft 360 degrees, and repeat the same process of checking the position of the piston, and valve then reinsert the TDC checking tool (the crankshaft shouldn't have to turn too much, just like it did before you removed the TDC checking tool. This process can be used on almost all other engines (preferably with the timing belt or chain off).