1967 F-100 Ranger 352 Need Help Timing

[BarneyGeo]

Working a little by little , changed plugs, wires, points, condenser today. I thought that would take care of the truck missing. I had a friend suggest turning the distributor a notch at a time but I have no idea of which way and where the make the turn. No timng gun available.

I get severe backfire if I am running 40mph. and the last time I ran it on the interstate I got a little over 55 and I thought it was going to fall apart. It acted like it wanted to die very rough but as soon as I let off of it and as soon as rpms slowed down it tried to idle. I can drive this truck anywhere as long as it it 45 mph! All help is needed!!!

Thanks guys,

Joe Arwood

[FNA]

Couple of things:

You're working on a 30 year old truck, you should have a service manual. This will tell you how to static time your ignition. It can be done, I don't remember off the top of my head and anyway, too much of a pain in behind to write out instructions.

If you don't have a manual. you can very likely find one at a library. Borrow from there, because you want to spend your money on a timing light. If you don't have the correct tools to do a job, you cannot do the job correctly. Simple as that.

Have you checked your advancer? These can freeze up, then you get no spark advance.

You want to make sure everything is on the money in ignition before you look to your fuel system which could also cause the symptoms you describe.

[unclebubbles]

Hey Barney
Sounds like the ignition is breaking down. Even though you changed most of the ignition parts theres still a few things you can check. You didnt mention putting a distributor cap on it. If thats the old cap, check it good for cracks and carbon tracking between the lugs inside and out, or just put a cap on it. Also, check the high voltage terminal on the coil, where the coil wire plugs in. If it sat for a long time, it could be full of corrosion. Also check the coil for cracks, it could be arcing. Your firing order is 1 5 4 2 6 3 7 8, and the dist turns ccw, to retard the timing turn it the same direction it rotates, ccw. Put a mark at the base of the dist and loosen the screw at the base of the dist, move it in small increments to see if it helps. I would check the other things i mentioned first though, also make sure the firing order is correct. As far as setting the timing with a light, thats ok so you`ll have a reference and know how many degrees your working with and where it`s set when you do get it running right. But trying to set the timing to the specs listed for that truck is a waste of time usually, unless you want to run hi octane fuel. Those specs were written 40 years ago when gas was real gas instead of the garbage they sell today. Try setting the initial timing to around 6 degrees and try it. Keep advancing the timing till it starts to rattle(pre ignition) , and then back it up till it quits. Once you get it set you can put a light on it to see how many degrees you have for future reference. If you cant get a light, just get it running decent and do the same thing, advance it till it pings then back it up. Also check the things FNA mentioned, the vacuum and the centrifugal advance in the dist. , check for vacuum leaks.

[BarneyGeo]

Hi,

Newbie here. First, Have you checked your advancer? what is this. I have changed the distributor cap and rotor button recently with wires. I will change the vacuum hose on he front of the distributor , its old needs changing, I will check coil inside where distributor meet. if corroded I will just buy one. cant hurt. Setting timing is that done while truck is running hot or cold? I will move it CCW, is this just a move or do I need to lift and change to next cog at bottom of distributor? I have been told that I had to lift up.

On the road it backfires like mad at around 45 when I let off quickly. Is this part of the same problem. When I set the timing I want it to be as smooth as possible correct. Thanks for the response and I really appreciate your help. I will let you know what happens, it is supposed to be 70F here tomorrow!!!!Let me know on those couple of small questions if you will.

Thanks so much!


Joe Arwood
Gaffney,SC

[mechhound]

Originally Posted by BarneyGeo

Hi,

Newbie here. First, Have you checked your advancer? what is this. I have changed the distributor cap and rotor button recently with wires. I will change the vacuum hose on he front of the distributor , its old needs changing, I will check coil inside where distributor meet. if corroded I will just buy one. cant hurt. Setting timing is that done while truck is running hot or cold? I will move it CCW, is this just a move or do I need to lift and change to next cog at bottom of distributor? I have been told that I had to lift up.

On the road it backfires like mad at around 45 when I let off quickly. Is this part of the same problem. When I set the timing I want it to be as smooth as possible correct. Thanks for the response and I really appreciate your help. I will let you know what happens, it is supposed to be 70F here tomorrow!!!!Let me know on those couple of small questions if you will.

Thanks so much!


Joe Arwood
Gaffney,SC

The advancer would be officially called the "centrifucial advance" It's inside the distributor and advances the timing as the engine speeds up. It consists of springs and weights. If you grab ahold of the rotor inside the distributor, you should be able to turn it some and then it should spring back to where it was. There is also a vacuum advance, that round silver colored thing on the outside of the distributor with a small hose about 1/4 inch in diameter hooked to it.(talked about before) Very common for the vacuum advance to go bad. No you don't have to lift the distributor up to change the timing. Mark the side as advised before, so you know where you're at with the timing. Timing would probably best be done with the engine warm when it idles the smoothest. Before I messed with the timing, I would recheck the gap setting of the points. Changing the points gap also changes the timing. I would check the point gap again anyway, because if the gap is too far off, the truck won't run right anyway. A little history of the truck would help. How long have you had it? How much has it been driven recently. Did it act like that on the highway before you tuned it up?

[G.A.S.]

Had to correct myself. wasnt thinking

[unclebubbles]

Originally Posted by G.A.S.

that backfireing is most likley the points closed to much. Re-set the points to the factory specs.
If you do turn your distributor even a lil bit you will have to re-set the points.
Make sure your points are new/clean.

The backfiring may in fact be from the points being adjusted wrong, but moving the timing will not affect the adjustment of the points. The point gap will remain constant no matter where the timing is set. Point gap(dwell angle) does have an effect on timing, but timing doesn`t have any effect on dwell. If you had to reset the points every time you moved the timing, you would be from now to eternity trying to get em set.

[G.A.S.]

Originally Posted by unclebubbles

The backfiring may in fact be from the points being adjusted wrong, but moving the timing will not affect the adjustment of the points. The point gap will remain constant no matter where the timing is set. Point gap(dwell angle) does have an effect on timing, but timing doesn`t have any effect on dwell. If you had to reset the points every time you moved the timing, you would be from now to eternity trying to get em set.

A. At ordinary engine operating speeds, the points open and close a couple of hundred times per second, the exact number depending on the number of cylinders and the engine RPM. The points need to be closed for a appreciable time in order to build up the maximum magnetic flux in the ignition coil core.
The period of points closure is specified by the ignition system designer and is typically expressed as degrees of distributor rotation. In a four cylinder engine, the angle between each ignition cam lobe is 90° and the period of points closure or "DWELL" is usually a bit over 45° of distributor rotation. In a six cylinder engine, the lobes are 60° apart and the dwell time is 30° to 35°.
The dwell is adjusted by setting the points gap to a specified distance at maximum opening. A narrower gap gives more dwell and a wider gap gives less. Taking it to extremes, excessive dwell means that the points close too soon after opening, cutting off the magnetic field collapse before it delivers all its energy. Too little dwell gives the magnetic flux insufficient time to build up to the maximum.
Both conditions give a weak spark which gets even weaker as the engine RPM rises and produces misfiring at normal operating speeds. The dwell, as well as spark plug gap, do have an effect on ignition timing. The later the points open, the later the spark comes and retards the timing. The earlier the points open the sooner the spark comes and advances the timing. That is why timing is the last thing to be set in a tune-up.
The way I set the dwell is this; remove the distributor cap and rotor, ground the coil wire and remove all the spark plugs from the engine. Set up your dwell meter and hook up a remote starter. Turn the key ON and crank the engine. Adjust the points to the desired setting and tighten the points. Crank it again to be sure the dwell angle is still correct.
With GM points it's a lot easier. They have an adjuster built into the points and a little door in the distributor cap. This allows you to adjust the points while the engine is actually running.