Not another Plug Wire discussion

Discussion in 'General IH Tech' started by NorCalDiesel, Nov 5, 2010.


  1. NorCalDiesel

    NorCalDiesel Farmall Cub

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    I am getting dizzy (no pun intended) trying to diagnose and fix my crossfire issue. At least I think that is what it is. It seems to be firing on cylinders that are not supposed to fire, cylinders with the exhaust and intake valves open as I am getting backfires and "Front" fires through the carb.

    When I put this scout back on the road in March I did not have this problem. At that time I replaced the cap, rotor, plugs and wires amongst other non related items like oil, filters, etc.. At that time it ran pretty good. About 2 months ago it began to crossfire and I was advised to check the plug wires to make sure they were not running over each other, etc.. I did that with varying degrees of success, but it has not fixed my problem. I am wondering if my distributor is just done.

    I have read all posts I can find on crossfire and tried everything in the plug wire routing directives to no avail.

    I have been thinking that it would be nice to have a more powerful and technically newer distributor/ignition. Therefore I am looking for recommendations for a MSD type ignition.

    I currently have a factory Holley Dist setup.

    Any and all advice is welcome.

    Thanks,
    Pat
     
  2. Eric VanBuren

    Eric VanBuren Lives in an IH Dealership

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    Is this the truck in your sig? If so does it still have points? You mention replacing cap, rotor, ect but there is no mention of replacing or setting the points and timing, the first step in a tune up. Points that are way out of adjustment can cause issues that seem like crossfire.

    If you are truly experiencing crossfire a stronger ignition system will only make it worse.

    If you do still have points they can be used to trigger a MSD. That takes the current flow out of the points so the actual contacts will last a very long time. The only wear will be the rubbing block so you will still need to lube the rubbing block and adjust the points periodically.

    The other option is to fit a Variable reluctance pickup and use that to trigger the MSD. Instructions for the various options are listed in the FI forum.
     
  3. Thomas

    Thomas Dreams of Cub Cadets

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    ---I would start with basic electrical and make sure that all grounds are top notch. Often, from the battery, front clip to rear, IH installed jumper wires made of 12 gauge wire. This ensured that a ground bypassed a seam, whether it be rusted or welded, from one body panel to the next. Again, steel conducts a maximum of 23% and minimum of 5%. Rusted steel can bring those figures even lower and rusty seams can create a 0 conductivity situation... even if only momentarily, while driving over railroad tracks.

    ---I'm fairly seasoned, but never had to deal with points ignitions, so all I can say there is that you should get yourself a dwell meter and not guess at what's right. Make sure that your air spark isn't gapping when it should be holstered. Just like the cam lobe separation, dwell keeps spark open for a certain degree. If dwell is off, I can imagine seeing it act as if the cam's lobes were out of sync.

    ---Other than that, you said "MSD Type", so I am guessing you didn't mean MSD as a company and were inferring "Multiple Spark Discharge" which can be acquired with something as simple as an MSC (Multiple Spark Coil), a distributor or electronic ignition of the MSD type.

    ---I'm very happy with the Unilite I purchased roughly 5 years ago. All my wiring is well over par (Ron Francis' Wire Works), grounds are nearly 100%, directly through copper or brass (no "body" ground through steel). A Body strap from the copper wire to the starter mounting bolt and a 10 gauge wire from the distributor mounting bracket to a brass stud that has a 10 gauge ground wire terminated to the other end. I installed the Unilite, Circuit Guard & resistor, as suggested by Mallory.

    ---In other words, no matter how good an ignition system you install, we must consider that it can only be as good as the wiring allows it to be. As I have always said, in short, it doesn't matter if it's OEM or aftermarket when it comes to shoddy wiring. Each will perform well, as well as be short lived.

    ---What spark plugs are you running, have you tried and have you fouled?

    -Edit (in regards to points ignition):

    ---I was about to take Fred out and he said "Solid Core Wires" Does it mean anything to you? Seriously, he talks.
    [​IMG]
     
  4. NorCalDiesel

    NorCalDiesel Farmall Cub

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    Thanks Eric, it is the vehicle in my sig. I did replace the points/cond and set them at .019. I don't have a dwell meter at the moment. My timing is set at approx -5 / 6 BTDC. With the new points it seems better, but still feels like it wants to hesitate and backfire. I have played with the timing and this is where it runs best at the moment. The reason I was thinking stronger ignition is related to fuel econ, not necessarily to fix this particular issue.

    I am assuming Crossfire because it seems like under power in any gear it seems like it will fire a cylinder that has a valve open, either exhaust (backfire) or intake (backfire out of the carb). I am almost 50 so I have had experience with points style ignitions before, but nothing as difficult to diagnose and repair. It also could be the carb, but I did rebuild it.. it's a Holley 2300 2bbl.

    I really need to rebuild this 304, but it still runs and it would be nice to drive it when needed as I source a replacement. I found a running 345 and thought I might go that route.

    Thanks,
    Pat
     
  5. 250gibson

    250gibson Binder Driver

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    Have you checked for sticking valves??

    In other words, the cylinders may be firing when they should, but a valve or may 2 may be staying open.

    Usually with either a valve or crossfire problem you will either get a backfire out the exhaust or intake, but not a combination of the two????

    A crossfire, doesn't just develop, so if it wasn't doing it before and nothing was touched, the wires cannot cross themselves, which may be why it is valve train.

    Just read that you replaced ignition parts. Are you sure that you got the correct replacements. I have read somewhere that there are different holley caps that all may physically fit, but may be off enough where you develop carbon traces in the cap which can cause a crossfire like condition.
     
  6. Thomas

    Thomas Dreams of Cub Cadets

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    ---Parked on level ground, fuel level set at sight plug's lower threads, barely trickling out while truck is running? Could it be that it's leaning out on you and backfiring due to acting like a vacuum/intake leak? Inlet hoses old/bad/cracked, fuel pump not puting out the required volume, sock in tank or filter restriction? Choke setting incorrect? Float sticking on rough area of the pin it hangs from? Bad accelerator pump spring or worn pump arm?

    ---Back to ignition though; Place a timing light on a wire and bring your rpms up. With me, peripheral vision shows me when a wire/plug is fouling cause it's more sensitive and allows me to see difference in pattern or strength. Move on to the next wire and do the same till you find nothing, or the culprit. Also, run the truck at night, with no light aiding vision, and you might see a spark plug wire arcing or the coil wire arcing to a post on the coil.

    ---Good point. I was going to suggest some* SeaFoam to gently clean the valves and lifters... where I use 4 ounces in oil, 4 ounces in fuel and half the can to choke the engine through the carb. I let it sit for the 5-10 minutes and then change oil between 50-100 miles to get any remaining solvent off my seals.

    ---I am guilty of not bringing it up because I thought he would have considered it, but with respect, thank you* for doing so.
     
  7. NorCalDiesel

    NorCalDiesel Farmall Cub

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    I have used Seafoam in both the tank and oil pan, about a month after I got her running. I did not guess at the points gap. It should be .019 when new and thats what mine were. When I had a dwell on the first set of points IIRC it was about 25 degrees.

    I went out and bought a new points and condenser and replaced them again, setting the points gap to .019 and it runs much better. Maybe, just maybe the 5 month old points/cond I had in there was bad, autozone.

    Back to the "points" you all mentioned, I have addressed most all of them except the sticking valve possibility. I went through two caps until I found one that fit correctly. For the Carb.. I have set a few Holleys up and believe this one is running fine. I rebuilt it and set it up correctly, the plugs say it is running ok, not lean or rich. I don't remember the plug number, but I got it off here and I know others run them. I also have a frame rail mounted electric Holley fuel pump in place of the original (I got it like this) and a glass fuel filter. I have great fuel delivery, but only one 10 gal tank.

    Anyhow, it seems to be running very good now that it has new points/cond. BTW, the timing is at 6* BTDC.
     
  8. sdowney717

    sdowney717 Farmall Cub

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    seeing all the IH engines running fine with that old Holley distributor, makes one think their is nothing wrong with it.

    Consider putting in a Pertronix ignitor and getting rid of the points and never worry about it again.
     

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