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Unread 02-15-2009, 07:18 AM   #1
rkbell
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1977 CJ5 
 
Join Date: Feb 2009
Location: Shiloh, GA
Posts: 487
304 firing order

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.

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Unread 02-15-2009, 09:59 AM   #2
khamill
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1972 CJ5 
 
Join Date: Jul 2008
Location: kansas
Posts: 55
The location of the wires on the distributor has only to do with how the distributor was installed. You can remove the distributor, turn it 180 degrees and reinstall it. If you move your wires to the opposit post on the cap (180 degrees) it will still work. Most likely, the distributor has been installed 1 tooth off from the common position and each wire was moved 1 post to make up for the difference. If the timing chain has slipped, it is possible that the distributor was advanced that far in order to make it run as you said.
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Unread 02-15-2009, 01:15 PM   #3
texasdave
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1980 CJ7 
 
Join Date: Dec 2007
Location: Killeen, Texas
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Some of the timing gears from that era had plastic teeth and would tend to wear or break. I'd start from scratch and pull the distributor and reset everything to ensure it was right. I would pull the grill and go into the front to check the timing gear and chains while doing your tranny. What's another day or two of work anyway? I think CJ-s were invented by woman to keep the husbands close to home and in the garage so they'd know where they were.
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Unread 02-15-2009, 01:31 PM   #4
JeepHammer
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1973 CJ5 
 
Join Date: Aug 2007
Location: South West Indiana
Posts: 10,431
Quote:
Originally Posted by rkbell View Post
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.
----------------------

First off,
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...

AND REMEMBER!

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,

SO,
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 ...

Personally,
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.

Last edited by JeepHammer; 02-15-2009 at 01:50 PM..
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Unread 02-15-2009, 06:53 PM   #5
rkbell
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1977 CJ5 
 
Join Date: Feb 2009
Location: Shiloh, GA
Posts: 487
Hammer, thanks for the good info. What do you know, there actually are timing marks under all that crud! I'll go through all the steps you told me and see how things fare. The distributor is a prestolite and has the 'D' shaped rotor shaft (I'd send a pic but haven't figured that out yet). There is a cover under the rotor that, when pulled exposes what I'm assuming is the reluctor (8 pronged thingamajig). First time I've ever seen one like this (obviously). I would be interested in info on the MC / HEI distributor setup you mentioned as I may be replacing mine anyway. Thanks.
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Unread 02-15-2009, 09:28 PM   #6
JeepHammer
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1973 CJ5 
 
Join Date: Aug 2007
Location: South West Indiana
Posts: 10,431
Quote:
Originally Posted by rkbell View Post
Hammer, thanks for the good info. What do you know, there actually are timing marks under all that crud! I'll go through all the steps you told me and see how things fare. The distributor is a Prestolite and has the 'D' shaped rotor shaft (I'd send a pic but haven't figured that out yet). There is a cover under the rotor that, when pulled exposes what I'm assuming is the reluctor (8 pronged thingamajig). First time I've ever seen one like this (obviously). I would be interested in info on the MC / HEI distributor setup you mentioned as I may be replacing mine anyway. Thanks.
Sure, ditching the Prestolite distributor/ignition module is one of the best things you can do for your engine!

Don't loose that bake-a-lite cover between rotor and reluctor, those are HARD to find replacements for and someone here running a Prestolite might want it!

The rest of the distributor is junk, and should be used as a core after you steal the drive gear off it! (if the drive gear is any good...)

The '79 Jeep/Motorcraft distributor from 304 V-8 CJ will do fine!
Hopefully, you get one that is actually from a '79, and it' will have FULLY ADJUSTABLE advance in it from the rebuilders.

They run about $50 plus core, and you can take your Prestolite back as core later to get your core charge back...
They never check, and if there was a shortage of these distributors, there would be more than a $20 bounty on the cores...

Upgrade the cap and rotor,
You are looking for a PREMIUM, BRASS TERMINAL CAP and premium Rotor for a '79 Ford F-150 Pickup with 302 V-8 engine.
You also want the 'Cap ADAPTER' or cap base from the same year.

The set will look something like this, and if you want top quality parts, MSD will send you this set from Summit...
http://store.summitracing.com/partde...5&autoview=sku



Wide rotor and tall cap will take charge of the spark energy you can produce, and this will make for some SERIOUS SPARK ENERGY CONTROL over that small cap and rotor you are using now!

Next step will be some plug wires...
'Cut To Fit' work best for me, since all the 'Off The Shelf' wires fit like crap for the high energy terminals.

I use this kit the most for V-8 engines,
http://store.summitracing.com/partde...5&autoview=sku

They aren't excessively expensive, but they are VERY good wires!
And they come with the crimping tool, both sets of terminals, advanced instructions, ect.

Then you are off to the module.
What I would use myself (and do!)
Inexpensive: $20 HEI style replacment module.
No resistor required, and your system doesn't have one build in.

Most of the wires you need to use are already installed, so that makes things EASY to wire up the new HEI module about where the 'Prestolite' module is today.

Have a look at this diagram,
Notice you already have wires to the distributor and coil in place, and the power wire to coil and module is already there?



Your factory tach (if you have one), should work fine with this wiring...

-------------------------------------

The EXPENSIVE way:
$130+ for a CDI module to fire the coil.
This is $130+ dollars for the module, but you will get an automatic 500% increase in spark energy!
And it's VERY easy to install!



You can pretty much make this thing a 'Plug & Play' with a few adapters...

--------------------------------

This is one of the adapters I suggest you spring for.
It adapts your distributor plug to wires you can plug right into the MSD or other CDI modules,
OR,
You can nip off the smaller connector, and wire in your custom application (HEI module)
http://store.summitracing.com/partde...5&autoview=sku



-----------------------------------

This is a 6 foot 'Extension Cord' for your low voltage ignition trigger wires...
It allows you to move the module up to 6 feet from the distributor,
and I have a tendency to mount my modules under the dash where they are away from *MOST* carnage, heat, mud, submersion, ect.
http://store.summitracing.com/partde...5&autoview=sku



Remember, you can always 'Nip' the module end connector off after it gets you distributor harness hooked up and transports the signal back to your module if you don't run a CDI ignition...
-------------------------

The only other issue that hasn't been addressed is the cap locator...
On these Jeep/Motorcraft distributors you get from the Reman builders,
There might not be a small sheet metal cap locator tab on the distributor when you get it.
Every distributor is drilled and threaded for the screw, but the tab and screw are often missing.



I make mine out of old tin cans... takes about 5 minutes...
15 on your first try...

As you can see, it's smaller than the clip that holds the distributor cap or adapter in place, and it's VERY simple to make...
(Many a one has been made from beer cans around here!)
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