Electrical Checking Timing Want To Think It Through First

Discussion in 'Fox 5.0 Mustang Tech' started by 7991LXnSHO, Aug 11, 2013.

  1. What a time for system updates!

    I decided to check if I needed a tune up - my mileage stank this last tank. I realized the timing marks lined up with the paint a previous owner had put on the circle of the timing marker. After I cleaned it up, I saw where the triangle edge is for really setting the timing. Strange! If I tried to turn the distributor that far, the cap hit the fuel hard line in the back. So I rotated the distributor innards a notch, and I can not get it to run with the timing set off of the right part of the marker. It runs fine set off the middle of the circle instead.

    SOOOOOO - what is the BEST way on a small block Ford, in a 1991 Mustang, to check TDC???? I am thinking, after it cools off, about taking an air chuck hold, (or an old spark plug without the ceramic in it), threading the middle, and putting in a stop bolt that fits in the spark plug hole. Then I'll get a big socket to fit over the harmonic balancer bolt to manually turn the crank with a breaker bar (so I do not jam anything) and mark it clockwise, counter clockwise, and split the difference for the real TDC. Will that work on a 302?

  2. If you don't have enough travel in the distributor to achieve proper timing, just move the distributor over a tooth. If the balancer slipped, you would either see the main crank pulley wobbling or see the rubber coming out between the two halves most likely.

    To check TDC
    1. Remove #1 spark plug.
    2. Plug the spark plug hole with a piece of paper.
    3. Either have an assistant short click the starter, or use a remote starter switch (a long screwdriver will also work to bridge the posts on the starter solenoid.
    4. When the paper is pushed from the #1 cylinder- compression stroke-, turn the engine by hand with a breaker bar and a 15/16" socket, until the timing marker is at 0 (TDC).
    5. To make sure it is at TDC you can GENTLY stick a small screwdriver in the spark plug hole to make sure the piston is at the top.
  3. I already had moved the gear one tooth. That is how I found there is no way the factory pointer is right now. It will not run with 10 to 14 degrees base adv timing measured from the right place. But it will run using the painted mark in the circle. Any other ideas why? It seems like a very short list of possibilities.

    So if it slipped years ago and they just marked the indicator tab, do I just replace it with an OEM rebuilt balancer? I do not plan on selling the car and a stroker is where I would go with a rebuild eventually. Besides a couple of Rattler brand balancers for Chevy when they came out, I never really sold SFI or super duper ones. What is the opinion on them? Worth it on a street car and what brand if so?
  4. if you moved 1 tooth then the plug wires might need to be move 1 hole over so that 10-14 degrees can be seen with timing light...i would really look at the rubber on that balancer first...any cracks :poo: can it asap
    stykthyn likes this.
  5. for street use on a stock 302 I see no reason not use a Dorman OE style balancer. Budget wise that is your cheapest option as well.
    7991LXnSHO likes this.
  6. Some of you guys seem to be be missing the point. It is the pointer or harmonic balancer, not the distributor that is off. I can make it run using the "wrong" marks someone put on, but not the factory triangle tip.

    Putting the distributor in no matter where, as long as the first wire lines up with the rotor, it should not matter which tooth IF there is clearance. Right?
    If I can measure exactly where TDC really is, I can hopefully use the info to replace the right part which should be the HB. The pointed looks like every other 5.0 pointer I have seen.
    Moving the distributor will not change where TDC is. If I understand right, it should be fixed mechanically between the inner balancer, crankshaft, rod and piston.
  7. Sounds like your balancer spun. Replace it.
  8. If it helps. The keyway on the crankshaft & balancer is at 12 o'clock at TDC. That should be "0" on the outside part of the balancer and pointer. You have to remove the balancer bolt and maybe get tricky with a flashlight and mirror to see it.

    With #1 cylinder at tdc the exhaust valve on cylinder #5 is open.
    #9 jAEded, Aug 12, 2013
    Last edited: Aug 12, 2013
  9. Also, make sure the spout connector is removed when you check the base timing.
  10. Any wobble in your balancer while idling? If so replace it. I just replaced mine as it was wobbling and pinging at 10 degrees. Saw some rubber sticking out on front side. Back was really bad didnt see that till I pulled it. Mine spun. Hope I caught it in time so my crank doesn't break. I replaced with a SFI pioneer...over kill on a stock engine I know but I've been having some big time issues with parts store parts.
  11. That was worth posting. I can confirm that it is what is off that way. I see no other way it could be the pointer, but this will confirm the right problem. Right now I do not see rubber sticking out, but I am afraid I will have to move the radiator to get the HB out. I think I will need the room for the puller in there. It has been years since I did a water pump or can swap on a Fox.
  12. N
    No wobble.
  13. I can do mine with the radiator in. You have more room with the pulley and fan off. I just used a 1/2" impact, short socket and craftsman steering wheel puller.

  14. You should have enough clearance with the shroud and fan removed.
  15. Is yours the stamped metal pointer? With a hole on the opposite side of the timing line. Kind of wraps around top left side of the balancer if you're looking at it from the front.
  16. First, thanks for letting me know I do not have to get wet and slimy in the green stuff!
    Second, the pointer is the same stock circle on the left, pointed triangle on the right as all the Mustang pics I have found. The center of the circle is where TDC was remarked in paint. With the spout plug pulled of course and in my pocket, that seems to be about how far off something is.
  17. No worries and sounds like you got this issue figured out.

    My balancer is a little different but it shouldn't matter everything should be at the same spots. Its at "0" in the picture. The keyway in crankshaft and balancer is at 12 o'clock with cylinders #1 and #5 at TDC.
  18. I replaced the HB, and I AM NOT SURE IT WAS OFF! The old and new ones looked like they are clocked the same way. So I tried using a skinny dowel to locate TDC for sure. When I was cleaning plugs, I tried to use a different cylinder with less interference first. But I could not get an absolute spot for cyl. #1! Frustrating! It is in the right neighborhood, but close does not count, and I think an added mark might be closer to right. I also saw another spot filed into the marker, and a deep gouge, both dictating this is not a new issue.
    1. How could this still be off? 2. If it still runs badly at the "right" spot, should I just run it where ever it runs best until I switch heads? Help, jrichker! Is other a special bend I need to use to check this cylinder?????
  19. It is still apart due to some other work I am doing in there.