I have a 79 351m I bought a timing light but i dont know how to do the timing. I got a hynes manual but i wasnt sure if i had it right. Can some one tell me how i am suposed to do it?
Thanks Dan

 

Engine should be warmed to normal operating temp before you begin. Make sure you have no vacuum leaks either or it will throw things off. Remove the vacuum advance vacuum line from the distributer and plug the line (if you don't you have a vacuum leak). Start the truck and with the timing light clipped or connected to the number one plug wire, point it at the timing marks on the timing cover and harmonic balancer. The mark on the balancer will appear each time the light flashes at about the same mark on the timing cover each time (a small amount of fluctuation is normal). The "0" mark is TDC (Top Dead Center) the numbers in front of the "0" are BTDC (Before Top Dead Center) the numbers after are ATDC. Check the location ot the mark on the balancer with the light. If it appears as the underhood information says it should, then no adjustment is necessary. If not, then you will have to turn the distributor to adjust it. To do so you must loosen the clamp bolt at the base of the distributor casting (against the block). Loosen only! DON'T remove the bolt and clamp. I can never remember which way advances and which retards the timing but it suffices to say that turning the distributor slighty (and I do mean SLIGHTLY) will advance or retard the timing. Turn the distributor and recheck the timing with the light until the mark on the harmonic balancer lines up with the nearest mark to the base timing setting indicated by the manual or the underhood information. When you are satisfied tighten the clamp bolt back down taking care not the let the distributor slip while you are tightening. (Common sense should dictate what aspects of this procedure are done with and without the engine running).

 

You will probably need the special 1/2" angle wrench to loosen the bolt for the shaft clamp, if it has airconditioning it will be more tricky. cheers

 

I find this really helpful: Mark your desired degree with a silver sharpie or chalk. I like the sharpie, cuz it won't fade for a while, and it reflects the light really well. To mark the balancer, just crawl under the truck and turn the engine until you can see the correct marks.

 

turning distributor counter clockwise will advance it, hence clockwise will retard it