Ive got a cj that Ive had for awhile with electronic ignition, I just got a '74 j10 with a 360 and points. My truck runs good until mash on the go pedal, then it spits and sputters and backfires. I wanted to fool around with the points some to learn about them so I checked the web, ask people about them and the tore into them. The truck still aint running right. When I first checked the points they were at. 007, they should be .16. The timing was 12* atdc, it should be 5* btdc. I adjusted the points to. 016, set the timing and drove it down the road. It was worse. Tried it 2 or 3 times and finally got to rev up to 3k without backfiring and even to 4-5k short burst without backfiring. Then drove down the road and it ran like crap. My buddy says to set the timing at 5* atdc and keep the points. I say buy the pertronix points eliminator kit and be done with it. But on that note should I get the kit or pay another $100 and just get a new distributor? I dont have clue how old the one in the truck is now, but it seems to be in good shape. What do you guys think?
I would take a look at the breaker plate in the dist. If the pivot point is bad, it will allow the dwell to wander. You can check it with a dwell meter or by disconnecting the vacuum advance and driving the truck to see if it gets better. I would also wiggle the shaft to see if there is play in the bushings, allowing the shaft to move.
Insure the polarity on the coil is correct. + to battery, - to distributor.
Clean the contacts on the points (be sure to readjust the gap to .016)and clean/inspect the ballast resistor.
Insure your secondary system is in good shape. Inspect the plugs for cracking, fouling, or excessive gap. Check your plug wires to make sure they aren't bleeding off, cracked, or grounding.
Insure the pigtail wire inside the dist is good and isn't touching anything when the vacuum advance kicks in.
A lean condition will cause missing and backfiring through the carb. I would have a hard look at it. Insure the accelerator pump is good and there isn't crap blocking the passages in the main metering system. An easy way to check the mains is to partially block the choke closed and run it around the block. If it runs better, then that will tell you it is lean.
If it is a Motorcraft 2bbl, it will be a very simple unit and well within your ability to disassemble and reassemble. I wouldn't hesitate to toss a kit in it.
Points are a good system. I would sort out the issue before purchasing an aftermarket electronic ignition, as a worn or bad distributor will cause the new unit to fail, and if it is another problem, such as the carb, you have wasted your money fixing something that isn't broken.
Now that you have a couple of guys respond, I'll try to explain this...
Originally Posted by CSP
I would suspect the carb more than the distributor in that situation.
I would suspect the carb might have something to do with it, no doubt.
If it weren't for the breaker point distributor of 'Un-determinate' age, I would go straight for the accelerator pump shot since it backfires trying to accelerate under load...
My knee jerk reaction was immediately "Late/Small Accelerator Pump Shot",
But then he explained they had been messing with the timing...
What I DO NOT want to do is have this guy messing with BOTH the carb and the ignition at the same time!
See if the carb is 'Dripping' fuel,
See if it has an IMMEDIATE accelerator pump shot, no bubbles or sputters, but leave either the ignition or the carb alone until he's finished with the other...
Going two directions at once usually leads to chasing a fart though a keg of nails! Makes things 5 times as hard as they need to be for the inexperienced...
You come out smarter on the other end, but REALLY beat up! The smarter part is you know NOT to compound 'Issues' to make an even bigger problem!
Originally Posted by big_o_tom
Ive got a cj that Ive had for awhile with electronic ignition, I just got a '74 j10 with a 360 and points.
My truck runs good until mash on the go pedal, then it spits and sputters and backfires.
I wanted to fool around with the points some to learn about them so I checked the web, ask people about them and the tore into them.
The truck still aint running right. When I first checked the points they were at. 007, they should be .16.
You don't set 'Breaker Points' with a feeler gauge.
The manual will give you a 'Point Gap' to get you started, but the ONLY accurate way to set your breaker points to maximum efficiency is with a Dwell Meter.
Dwell is the TIME the breaker points are open, not the maximum lift like a 'Feeler Gauge' reading is.
Without proper 'Open' and 'Close' time ('Open & Close' are used as an electrical term, meaning they are electrically connected or the circuit is 'Open'),
Without the proper 'Saturation' time (Closed) the coil CAN NOT produce a strong magnetic field that produces your spark.
Without the proper 'Open' time, that spark can not fully form and discharge at the spark plug.
Things like shaft and bearing/bushing wear, worn lobes, ect. can all screw up the Dwell, and that causes real issues, much like you are describing.
One thing you should check once you have laid hands on a Dwell Meter,
Set your points for the correct Dwell Angle Reading,
Then REV the engine up, See if the Dwell drifts around.
If it drops like a rock (and you may have to actually drive the vehicle with the Dwell Meter hooked up) and the Dwell drops,
Then you have worn distributor housing bushings and the shaft is deflecting away from the breaker points screwing up your dwell time.
The timing was 12* atdc, it should be 5* btdc.
You maybe confusing the screwed up AMC V-8 timing cover. I don't know your level of ability, so I'll cover this just in case you don't know it already.
AMC confused things with a big 'A' (for ADVANCE) on the cover right next to the timing scale,
While everyone else in the world used a 'Before' or 'BTC' (Before Top Center).
Notice the 'A' is to the LEFT of the TDC, this means it's 'Advance' instead of 'After' like on every other timing scale in the free world...
I adjusted the points to. 016, set the timing and drove it down the road.
It was worse.
Tried it 2 or 3 times and finally got to rev up to 3k without backfiring and even to 4-5k short burst without backfiring.
Then drove down the road and it ran like crap.
My buddy says to set the timing at 5* atdc and keep the points.
I say buy the pertronix points eliminator kit and be done with it.
But on that note should I get the kit or pay another $100 and just get a new distributor? I dont have clue how old the one in the truck is now, but it seems to be in good shape. What do you guys think?[/QUOTE]
My personal reaction is...
If you don't want to fool with it again, replace the distributor with something that is...
2. You can get parts for ANYWHERE.
I would do a few things first,
How old is the distributor cap, rotor, plug wires, plugs, ect.?
If you are going to replace them anyway, then I'd replace the distributor with a '79 AMC V-8 distributor (Motorcraft) and do the cap, rotor, plug wire upgrade.
You will only be out an extra $50 for the distributor and about $20 for the module of your choice, and you won't have an issue in the world with this setup, a ton of us are running it, and it's an 'Upgrade' in every sense of the word.
If you have a lot of time and no money, and are pretty handy with a file, dremel tool, ect, you can try this...
WARNING: This IS NOT for guys with no patients or skills, (internet blowhards beware)...
If you are pretty handy with a file and can do some soft metal shaping, this is REALLY CHEAP, as reliable as an anvil, the only parts you change that will fail can be picked up at ANY discount auto parts store...
The distributor shown was doing EXACTLY what you are describing, it would pop, sputter, backfire, blow down though the pipes and generally run like crap.
When it put a dwell meter on it, instead of the usually 28 to 31 degrees, it would take a notion to drop to around 12 or 15 degrees when you tried to rev it up...
The bushings in the distributor shaft are worn, but with electronic ignition, there is an air gap between reluctor on shaft and trigger, so a little wobble doesn't mean a thing...
$15 worth of Chrysler trigger parts, a round hand file, a sanding roll on the dremel tool and about an hour of time converted it to electronic trigger, and the only part that can go bad is the electronic trigger, and it's off the shelf at any parts store for around $10.
This particular Chrysler style trigger is almost as accurate as a GM HEI,
Trigger signal is almost as strong as Ford/Motorcraft,
Will trigger almost any of the factory or aftermarket ignition modules,
And remember, with some MSD racing parts for the distributor cap/rotor,
You can fix that annoying GM Short rotor that blows through and the small diameter distributor cap that will become a problem once you convert to an electronic ignition.
If you need to replace cap, rotor, plug wires anyway, the $35 extra dollars you will spend on the cap adapter and REUSEABLE/REBUILDABLE blow proof rotor are well worth the money!
NOW! THIS IS NOT "NECESSARY" unless you are going to be pulling heavy loads or doing SERIOUS off roading, as in 'Expedition' vehicle off roading...
This is DUAL IGNITIONS...
If you are pulling HEAVY loads, you can off set one trigger by about 7 to 10 degrees or so, and with the flip of a switch you can default and retard the timing for heavy loads, while running more advance with light loads on the highway for better fuel mileage.
With the 'Heavy Load' version, you DO NOT need a second module, coil, ect.
Fire departments with older vehicles like this because they come home without several thousand gallons of water in the tank, and it adds reliability to their vehicles when installed with dual coils/modules.
If you are building an 'Expedition' vehicle which will be FAR from help, this gives you a completely REDUNDANT ignition system.
The second trigger, module, coil and switch gives you an IMMEDIATE back up ignition at the flick of a switch.
Search & Rescue departments purchased several of these a while back, and seem to be VERY happy with the results since they have a completely redundant ignition system instantly.
With both of these systems, you can flip from one ignition to the other running down the road and you won't even notice a missfire (If one occurs), they are that seamless.
So many of the folks here called 'BS' when I first posted this, one guy said he had 50 years of ignition experience, tried this dozens of times and it NEVER worked, so I couldn't have POSSIBLY figured it out...
After some of the guys from the forum wheeled with me, tried it out for themselves, ect. it's not just internet noise, it works.
You can also do it with the Jeep/Motorcraft distributor, but it's a little more involved, and you will have to do some cutting/welding on the trigger plate since I don't manufacture/sell the dual trigger plate anymore.
If you decide to get this involved, and you by no means don't need to do this unless you are building for EXTREME conditions, I'll supply the information to you for free if you go the Motorcraft distributor route...
Thats a lot of information, very good information. I want to learn to use the points, but right now I need to have this truck running decent and reliable. My wifes car has been in the shop on and off for 3 months, shes been driving my s10, which I need to put a spider injection on. Ive been driving my cj which needs a new rear driveshaft(first time ever that I have a u joint cap spinning in the driveshaft), and a rear yoke(I think the splines are worn, Im hoping the pinion is still good). First thing is my timing scale isnt like the posted above, it shows R10--5--TDC--5--A10. Originally the timing was on about A12, I set it to the 5 between R10 and TDC, which I think is 5*BTDC. Second thing is after I got the kit installed in the distributor while checking the gap between module and the magnetic ring I noticed a wobble, it seems that the plate that the rotor screws to must be bent some. Its not bad and actually I dont think it would matter with a stock set up, but this new unit mounts to that plate and is triggered from it. I guess all I can do is try it out. Oh yeah, Im not building expidition type 4x4, rock crawler or mud bogger. Its just a jeep truck(best in the world, imho), that I'll drive to work some, haul my boat, and might even take it to the mountains.
Well, the short of it is...
There aren't many 'Breaker Points' men around anymore. Mostly in older farm tractor stuff that work with magnetos.
In my early days of racing, we used a lot of 'High Pressure' and 'High Volume' oil pumps.
Since the oil pump is connected to the distributor shaft, that was murder on the drive gears, the bushings in the distributor, and keeping breaker points working correctly...
Age, poor lubrication, dried out grease, no oil on the felt in the distributor, dry top bushing all contribute to the same thing as the racing conditions, just slower...
Shaft wear can only be assessed in two ways,
1. A micrometer or dial indicator on the shaft, and some inside hole gauges and micrometer,
2. Watch the Dwell Angle readings while you are driving.
If that Dwell drifts around, especially dropping, you have a worn out top bushing in the distributor, and probably a worn shaft.
This DIRECTLY effects the time the breaker points stay open/closed (Dwell) and no amount of 'Feeler Gauges' is going to show you that.
Like I've said many times on here and other places, and everyone argues the point,
The ONLY way to tune breaker points CORRECTLY is with a dwell meter.
The 'Gap' setting specified in the manuals is a starting point, not a 'Tuned' set of points...
If the top of the cam lobes on the distributor shaft are worn, and you 'Gap' the points, the points are closing way too soon.
That screws up the TIME the coil has to saturate/discharge and the vehicle runs like crap.
Shaft wear will cause the dwell to drift around, and again, that screws with the TIME the coil has to saturate/discharge.
When we pulled a breaker point distributor, the first thing we did was pull the top bushing, install a new one,
Gauge the shaft, and ream the bushing to fit CLOSELY to the shaft so it couldn't move around a bunch.
Then you lift the advance plate, check the grease well that keeps that bushing lubricated.
99/100 times it will be dried out and NOT lubricating, so the bushing/shaft wear faster than usual...
You can't buy Lithium Soap for lubricant anymore (EPA says it's dangerous, even in small quantities in a distributor), so use that white chain lube grease instead,
And if you can't find chain lube that's not in a spray can, use a high quality FULL SYNTHETIC grease. Not the high temp kind...
You used to be able to buy all the parts, including the bushings, but they don't sell that stuff anymore.
The two parts you will NOT find are upper bushings and the 'Wave' ring that holds the breaker points plate in the distributor.
The wave ring is in a groove on the upper bushing, right above the advance/breaker plate, so DO NOT LOOSE IT!
Your other choice is to switch to an ELECTRONIC TRIGGER with a module,
Or buy a replacement distributor that is tight and ready to go.
I still don't install replacements without checking the grease well under the advance plate, but that's just me...
To do that, you have to take the gear off the shaft, pull the shaft up and out, then remove the advance plate/breaker plate.
That's when you will find the 'Wave Ring' just above the advance plate on the center bushing.
Once it's removed, you can lift off the advance plate and check the grease well for the top bushing, if you so choose,
Or if you decide to tear down your current distributor to see what's going on.
Now, one bit of trivia you need an old distributor man for,
There will be a 'Divot' drilled into the apron of the drive gear.
That divot looks like a hole someone started, but didn't finish.
Your gear goes back on with that divot facing the rotor nose.
There are 13 teeth on a distributor gear, so that divot is 'Front'. Uneven number of teeth means if you get it on backwards, you will be about 1/2 tooth off on rotor phasing, so pay attention when you take it apart, check for rotor direction and divot.
Some replacement gears don't have the divot, so make one before you take the gear off, or at least mark the side of the gear that faces the rotor nose...
Just some information from an old ignition man that might help, take it for what you paid for it...
I wouldn't worry much about the Wobble in a breakerless conversion.
The only beef I have with Pertronix is they fail fairly regularly, and you are completely stuck until you get a replacement from Pertronix.
No 'Off The Shelf' parts can get you up and running at the local discount parts place...
Breakerless, either Reluctor or flying magnet, which I suspect you have flying magnets, are perfectly acceptable for what you are doing... Air gap is REQUIRED for it to work, so a 'Wobble' isn't an issue most times.
Now be aware, with flying magnets, SLOW CRANKING SPEED might not get the ignition firing or firing correctly.
So old weak batteries, or slow dragging starters might be an issue for you.
Flying magnets need considerable speed past the trigger to work, that's why so many of the older electronic ignitions used a reluctor with magnetic trigger core to trigger factory ignitions... They send a stronger signal at slow cranking speeds.
If you decide to go back to breaker points, the above information might help you with that...
If not, maybe someone else can use it.
Well I took the pertronix back, bought a dwell meter and a new set of points. Got home and was cleaning all the electrical connections and for some reason the coil started oozing oil out the top. So I had to make another trip back to town for an accel 40,000 volt coil. I should have it running tonight, hopefully!
I got the new points, condensor, coil and rotor cap installed. Gapped the points, set the timing then hooked up my new $60 dwell meter. The drell is supposed to set at 32-34, it was on 46. I got down to 42 before it started running bad. Why is so high? What do I need to do to get it down to where it should be?
Most dwell meters come with a switch for the number of cylinders your engine has. Be sure that the switch is on 8.
Insure your meter is connected properly. Pos to the dist side of the coil and the neg to ground. If it has a secondary set of cables to power the unit, insure they are connected.
I have disagreed with JH on the "need" for a dwell meter to set points in the past. That being said, I'm not posting this to start another spitting match like the last one.
Many of us have set point gaps with feeler gauges with excellent results. While he is right about the dwell meter being more accurate, IMHO, setting up the points with a gauge is more than adequate on these old motors, and you may save 60 bucks in the process.
I had the dang wires to the dwell meter jacked up. Got the dwell set at 34 at an idle, it drops down to 32 around 1500 rpm, does this sound normal. Most of the sputtering and backfiring is gone but theres still a little something going on at higher rpms. Got to change out the heater core next then Im going to start on the carb.
Well....if aint one thing its definately another! Started my truck today to let it warm up, since it was about 20 degrees and snowing. It was running just fine then I had to shut it off to go start my s10 and defrost the windows so my daughter could drive it to work. Went back to restart my j10 and it wouldnt fire, it would crank but not fire. Checked the coil and it has 1.2 ohms and the other check that I cant remember the name for was 8.8(checking the center of the coil and the negative terminal), checked the coil again. The solinoid switch just went bad also, havent got to swap it out yet. That ony controls the starter, right? Whatever it is, Im not getting any fire to the spark plugs. Pretty sure its something simple, any ideas?