Setting Timing
From a post by Dan S.
0. Assumptions: all four wheels on ground; accessory belt splash shield removed; distributor access panel removed; spare tire out of the way.
1. Chock another wheel for safety and then place a floor jack under the right rear suspension and raise the tire until it is clear of the floor; release hand brake; engage 4th or 5th gear.
2. Locate the "window" in the trans bell housing. Yours might still have the factory plastic "top-hat" cover inserted in the window. The window is at the 12 o'clock position, directly under the t-stat housing. Remove plastic cover. Highlight the three hash marks ( 0°, 5°BTDC and 10°BTDC) in the bell housing with white or yellow paint.
3. Locate the opening in the yellow timing belt cover at the 12 o'clock position. It should still have a black plastic cap, if so, remove cap.
3.5 Optional: remove spark plugs to make rotating the engine easier.
4. Using the right rear tire, grasp the tire and slowly rotate the tire clockwise (forward...NEVER backwards) until the mark on the cam sprocket lands under the pointer stamped into the metal timing belt cover backing plate. There are marks on both sides of the sprocket. If these are not highlighted with paint, do so now.
5. Go to the other side of the car and look for a dot on the flywheel. It should be perfectly lined up with the 0° hash mark on the bell housing. Now's a good time to paint the dot with white or yellow paint.
5.5. If no sign of the dot, your cam/engine timing is off and you'll have to start over.
6. If you see the dot but it's not exactly on zero, recheck the cam sprocket hash mark to cam cover pointer relationship. The cam cover pointer needs to be exactly pointing to the sprocket hash mark, which points to a valley between two teeth on the sprocket.
7. If any deviation from exactly zero, rotate the tire clockwise again until the cam sprocket mark comes around again. If the cam sprocket hash and the flywheel dot cannot be synced to TDC, then your timing belt is wrong (maybe you're off a tooth or three) and you'll have to start over.
8. Let's assume that your flywheel and cam marks are perfectly aligned. Good...now engage the hand brake. (It's not a perfect way to keep the engine from rotating but it's all we have.)
9. Next, look at your engine accessory belt pulley and see where it is in relation to the timing mark on the pulley and the stamped steel timing pointers that are part of the sheet metal pieces surrounding the engine pulley. (You did paint the engine pulley timing mark, right?) Look at this relationship from the exact place where you'd point a timing light at the pointers and the pulley. If the 0° (aka TDC) pointer does not line up perfectly with the engine pulley hash mark, loosen the 10mm nuts holding the sheet metal pointer and adjust so that, from the perspective of where you'd be looking while using a timing light, the 0° pointer is lined up with the pulley hash mark.
The sheet metal piece that has the pointers was intentionally made with elongated holes for adjustment using the flywheel and bell housing marks as the reference point. If you don't check this when replacing the sheet metal belt surrounds, your pointers can be off by as much as 8°.
10. OK, at this point, all of our pointers and hash marks are synced at 0° TDC for cylinder #4.
11. If you have the OEM-style side-loading distributor cap, determine which lead is for cylinder #4, then follow the electrical path across the cap and down its side to the edge where the cap meets the body of the distributor. If you have an aftermarket top-loading cap, just find the lead for #4 and go down from there to the distributor body. Make a paint mark on the body of the distributor at that point.
12. Remove the cap, take a look inside to see if all is in order, then set aside. Use a 13mm wrench, loosen and remove the nut and washer and then remove the forked hold down. Clean the area around the base of the distributor and lift up and out of the block about 2" and hold it at that height, which allows the distributor's splined shaft to disengage from its drive inside the block. If the vacuum advance capsule on the distributor was too close to the timing belt cover, now is a good time to correct that, by rotating the distributor body counter-clockwise a bit so there is around 1" of room between the vac advance and the cover. Next, still holding the distributor up about 2" from its base on the block, rotate the rotor so it points to that mark you made on the distributor body.
13. Now, while maintaining the rotational position of the distributor body, lower the distributor body into the block and you'll feel the splines on the shaft engage the drive inside the block. If this displaces the rotor so it's no longer pointing at the mark, simply raise the distributor body up again, reposition the rotor, and lower it again. Refit the forked holddown, and its washers and nut. Tighten finger tight and then lightly snug down with the wrench.
14. If you have a side loading cap, temporarily refit your distributor cap (making sure to engage the indexing bump in the cap bottom edge with the notch in the top edge of the distributor body) to make sure your the HT wires are more or less aimed at the left rear shock tower. Remove the cap and set aside.
15. Release the hand brake and using the tire, turn over the engine an even number of revolutions and stop at TDC. Your flywheel, cam, engine pulley, and distributor marks should all line up. Try it couple more times, just to be sure. Reset hand brake.
16. At this point the crank, cam and distributor are all timed to TDC of cylinder #4, which is how FIAT does it. Now let's get ready to start the engine and set the ignition timing.
17. Reinstall the distributor cap and engage the retainers. Loosen the distributor holddown until it's finger-tight. Get out your timing light and because we are all so used to doing this from #1, connect to cylinder #1 HT lead and to power. Check that leads and cables are out of the way.
18. Start engine and run for 2-3 minutes until it settles.
19. Making sure your timing light advance feature (if it has it) is set to 0°, check the ignition timing either at the pulley end or the flywheel end of the engine. It should be somewhere on the 0°-10° scale depending on how you aimed your rotor.
20. If timing is retarded (meaning anything less than 10°), carefully rotate the body of the distributor counterclockwise to advance timing until it shows 10°(for an FI car).
21. If timing is too advanced (meaning anything greater than 10°), carefully rotate the body of the distributor clockwise to retard timing until it shows 10°.
22. If your timing light has an advance knob, you can dial in 10° of advance and then sync up to the 0° pointer.
23. Now that we're in the ballpark, follow the shop manual procedure for setting the ignition timing (wait until up to operating temp, set correct idle speed, etc etc).
24. Lastly, don't forget to tighten the distributor hold down.