How can one advance the timing if one does not have a timing light? I rebuilt my carb and replaced the plugs, wires and points yet the truck still idles rough. It is a 352 engine. Thanks

 

I dont recommend messing with the timing without a timing light. They're cheap, buy one.

 

I guess you are right. How does one know if you should replace the distributor?

 

If it won't turn, or the shaft wobbles excessively, replace it. Everything else can be repaired.

-Scouder

 

Depends on what's the problem. Rough idle could be vacuum leak, bad dizzy, carb problem. You've replaced some of the things that could be the problem.

Check the play of shaft in dizzy. If you can wiggle the shaft then this could be causing irratic timing/point opening, thus causing rough idle.

Autolite carbs are known for problems, even after rebuilt. If the throttle shafts are worn enough it will have a constant vacuum leak that will cause problems. Try spraying some carb cleaner around shafts when motor is running and see if it causes a change.

Just some thoughts.

 

Check the play of shaft in dizzy. If you can wiggle the shaft then this could be causing irratic timing/point opening, thus causing rough idle.
Try spraying some carb cleaner around shafts when motor is running and see if it causes a change.

Just some thoughts.[/QUOTE]



There is some play in the shaft, perhapse 1/8 of an inch. Does that mean i should replace the whole distributer? What shafts do you mean?

 

As far as setting the timing without a light, use the good old fashioned "power timing" method. Run the revs up to 3K or better and move the dizzy both directions until she just "sounds the best"

The only analogy I can come up with, is that it is very similar to adjusting the idle mixture. When you are power timing, you will see that as you retard the timing it starts to sound lazy and weak. As you advance it , it will sound stronger, to a point, then it may start to miss or even ping. Pick a setting that is more on the advanced side.

Some other factors to watch. If it starts to "kick back" on the starter you are too advanced. If the engine pings under moderate to heavy accelleration, it is too advanced. An engine that is slow to rev or a vehicle that just feels lazy is usually retarded (like me).

If you have a stop watch and a good clear road, the best way is to run 0-60 timed runs. Start with the dizzy pulled back a few degrees, and time it. Keep advancing the timing until it either slows down on the 0-60 run OR it starts to ping. You want to run as much advance as you can with out pinging.

CAVEAT( this is the legal disclaimer that makes me immune from any flames) The above methods assume that every other aspect of your tune up is optimized. The plugs, wires, cap, rotor, condensor, points, carb....all have to be just right.

BTW, the 0-60 timed runs also help with jetting and other tuning issues.

Have fun and smoke a few for me (tires guys, sheesh what were you thinkin"????)

 

I like the thoroughness and fundamental impact of strokster's method, but this method is a little simpler... As you have a quiet exhaust and know what engine knock (also called ping, detonation, auto-ignition) sounds like, you can bump up the timing a little at a time on regular gas, drive it with a heavy foot, and listen for it. Then back off a little, depending on how it runs or much knock you want to have or can tolerate. Some folks call light knock at wide-open-throttle the "sound of fuel economy".

Another way is to adjust the timing to whatever makes it idle the highest and then back it off until the rpm drops by 40. I heard the rule, tried it once on my dad's old Dodge van and it was amazing! (Van's are hard to time with a light because of the crowding under the "hood".)

Good luck.

And if you doubt this or question its wisdom at all, play it safe and buy a timing light. As Rusty said, they are cheap.

 

Or buy a six pack and make a new friend....that has a timing light.

 

What exactly do i turn to advance the timing while the motor is running? wont i get shocked?

 

You need to loosen the distributor and turn the body. Advance by turning the dizzy against the rotation of the rotor, retard by turning it with rotation. Read up on it in your manual.

If you grab a plug wire or coil wire that is not well insulated you can get shocked. But you have not lived until you get bit while tuning your monster. It is a right of passage. You might wet yourself, but it won't kill you.

Sorta like peeing on an electric fence....oh wait, that's another story.

 

I remember grabbing the top of the dizzy on my old 390 back when Strokster and I used to run together. It knocked the **** outta me. What was cool was that I felt the shock make a circle in my palm as the rotor spun. Strokster might have seen it happen if he hadn't been busy peeing on the electric fence.

I grab the sides of the cap now to turn it, not the top.

Strokster is right though. You haven't lived until you have felt 40-50,000 volts surge through you!

-Scouder

 

Well, i did it without a timing light and it runs MUCH better. When i get a timing light i will fine tune it but so far so good. I also replaced the vacuum advance an now the ticking noise that i thought was a bad lifter is now gone. Just need an new pcv valve and i should be good. Thanks for all the help.

 

just turn it by the vacuum advance

 

could you use just a dwell tachometer?