Originally Posted by rkbell
So I'm waiting for the valve covers to dry (paint) and I start digging in to why my CJ5 / 304 runs a bit rough, high idle, dies at stops when hot, etc, etc. When I trace the plug wires, it seems they are all off by one post clockwise on the distributor. If that was the case would it even start and run? Could the previous owner have advanced the timing so far out in order to make it run? I can't crank it now as I'm rebuilding trans etc. Thanks.
Depends on what you mean by "Advanced So Far"...
Timing your distributor is like every other Mechanical thing on the engine, Either it IS CORRECT or it IS NOT CORRECT, there isn't much gray area.
When timing chains jump teeth on sprockets, a lot of people move the plug wires around one space on the distributor cap trying to catch up with the rotor again.
Some people just don't get the distributor located in the correct place...
Don't know if they are too stupid or too lazy to make the distributor correct before bolting things do, but it's QUITE common.
When the rotor is out of phase with the actual firing cycle, that is a pretty good indicator you have trigger problems,
Advance plate stuck, reluctor in the wrong spot, ect.
Flip the distributor cap so you can see the rotor,
Then turn the engine so you can watch the rotor, with it starts to move, make a mark at the 0° (Zero) mark on the timing cover.
Then turn the engine backwards, but just until the rotor BARELY TWITCHES,
JUST BARELY STARTS TO MOVE...
And make a second mark at the 0° (zero) mark on the timing cover.
You should have two marks on the balancer showing on your timing scale now if you did this correctly.
More than 5°-7° slop in the timing chain is about normal for Jeeps.
More than 10°-15° and you are looking at serious chain stretch problems.
To try and clear your engine up, you need to VERIFY
everything about your engine timing.
VERIFYING COMPRESSION STROKE.
That means taking the #1 spark plug out, and turning the the engine over BY HAND until you find compression starting in the #1 cylinder.
VERIFYING TDC OF #1 PISTON.
TDC (Top Dead Center) can be found easily enough by using a wooden dowel rod or chop stick in the spark plug hole, and feeling for the top of the #1 Piston as you turn the engine BY HAND.
When the piston reaches the top of it's stroke, you have found and VERIFIED TDC OF #1.
Then take a look at the harmonic balancer mark,
And see if it lines up with the timing scale on the engine front cover.
If it lines up with the 0° (Zero) mark on the front cover (more or less,
Then the outer ring on the balancer is probably still good and giving a (more or less) true reading.
This means you have VERIFIED THE BALANCER.
Move to the distributor,
Find the #1 plug wire, or where you think the #1 plug wire should be, and mark the distributor BODY, NOT THE CAP!
Remove the cap, and see if the rotor is pointing (More or less) at the mark you made.
If it is, you have VERIFIED the distributor placement
If not, you have a problem!
If the rotor is half way between terminals on the cap,
The RELUCTOR is probably in the wrong place.
If the rotor is one complete wire terminal off, then you need to lift the distributor and put it back in where it belongs so the rotor nose is pointing at the #1 terminal when fully installed...
The distributor gear is gut on a 'Spiral' so the rotor nose is going to turn CLOCKWISE as you install the distributor..
So back it up almost one full space before you install it on a V-8, about 3/4 a full space on a I-6 and it might take more than one try...
Make sure the distributor SEATS FULLY before declaring victory!
Normally, your oil pump drive shaft will hold the distributor about 1/2" up from seating,
Turn the engine TWO FULL REVOLUTIONS.
The distributor will drop on the oil pump in less than 1/2 Revolution, but you MUST continue to turn the engine over 2 (TWO) full Revolutions to bring the engine back to TDC of #1 on COMPRESSION.
One turn will land you on TDC of EXHAUST STROKE, and the distributor will show 180 Degrees out when the balancer mark lines up with the timing scale!
REMEMBER, this usually takes more than one try to get the distributor in the engine in the correct place,
With the distributor gear on the correct place on the camshaft gear, but it doesn't cost anything but turning the engine over by hand, so make sure you get it right!
Once you have proper distributor placement, you can start to look for problems like rotor position and rotor phasing problems....
Cut a hole in an old distributor cap so you can see the rotor at work with a timing light...
And see if it 'Sweeps' past the #1 terminal when vacuum is applied or released from the vacuum advance.
When the Reluctor is triggering the Ignition correctly, you should see the rotor start at one side of the #1 plug wire terminal, and 'Sweep' past the terminal to the other side.
If it starts at the terminal, or worse yet, past the terminal, and continues to move away from the #1 terminal,
Then you have a SERIOUS rotor phasing problem.
With Jeep/Motorcraft distributors, this is easy to fix.
With Delco points distributors, or Delco HEI distributor, it's virtually impossible to fix...
There were TWO ways of holding the Reluctor on a Prestolite Distributor used from '74 to '77 in CJ engines, and since BOTH have shown up in all sorts of engines, without pictures of yours, I can't tell you which you have, or how to fix it.
Most will have the 'D' shaped top to the shaft to keep the reluctor true,
And they require a gear puller to get off, and gauges to line up when you put them back on ...
I would fork over the $50 Reman distributor for a Jeep/Motorcraft distributor and use a $20 HEI module for triggering.
This will give you an UPGRADEABLE, RELIABLE ignition for your jeep with 'OFF THE SHELF' parts you can get from ANY discount parts store in the country.
This will give you a full 12 volts to the ignition coil, slightly increasing your Usable Spark Energy
, and it's pretty easy to wire from scratch in your vehicle since you don't have a ignition resistor in your wiring.
Most of the wiring is already in place,
Key switch to coil/module power wires,
Coil to module wires,
Distributor to Module wires, ect. are already in place.
And it will work with your factory tach if you have one.
Let me know if you want details...
Your Vacuum Advance Nipple should be pointing at the drivers side headlight back,
And the firing order should be 1-8-4-3-6-5-7-2 CLOCKWISE.