Engine Struggling with the rebuild

Discussion in 'Classic Mustang Specific Tech' started by stevebr, Feb 28, 2013.


  1. stevebr

    stevebr New Member

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    I just finished rebuilding a 289 for a '67 coupe and the darned thing won't catch when I start it. We have gone back over the wires (getting spark), the firing order order(tried it a 180, just in case), check TDC 10 times (checking valves as well) tried two different carburetors ( the original and a Holley), Advanced and retarded it as far as we can, and the darned thing won't catch. I'm open to any suggestions or ideas of what the probem might be.
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  2. Falcon79

    Falcon79 Active Member

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    Ill repeat the old mantra...Fuel. Air. Spark.

    Are you getting fuel pressure from the pump? How about a compression test?
    #2
  3. palerider94

    palerider94 Member

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    any blow back out of the carb - would show timing issues. Put a paper towl over carb and crack and see if it blow off.
    #3
  4. woodsnake

    woodsnake Active Member

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    Did you prime the carb? Are you drawing fuel from the tank yet?
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  5. horse sence

    horse sence Please don't call me Mom SN Certified Technician

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    i built a 390 for a boat,had a bunch of people over couldnt concentrate on what i was doing and wired the dist clock wise instead of counter clock wise .soon as every one left i checked every thing again and found what i had done. changed the wires and it fired first turn.
    if you are getting spark at the plugs i would say fuel ,as woodsnake said prime the carb.
    #5
  6. SHEDRED

    SHEDRED New Member

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    Sorry to hear so much trouble on a new build. Are your coil wires reversed and if not have u checked for 12 volts at the coil both b4 starting and while cranking to fire engine? Any loss of voltage and no start is the problem. Remember it may still show a spark with coil wires reversed just wont be near the intensity needed.
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  7. rbohm

    rbohm Founding Member

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    start with the basics;

    run a compression check

    double check your ignition wiring

    make sure you have proper fuel pressure

    make sure you have fuel to the carb
    #7
  8. 68keyblr

    68keyblr Member

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    We had a similar issue when trying to start my mom's 331 after the build. We had spark, but it wasn't a strong blue/white spark it was orange-ish. We noticed the starter was laboring even though the battery was fresh and on a charger. We replaced the starter and it fired right up. The old starter was apparently draining the power from the system
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  9. stevebr

    stevebr New Member

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    Some great suggestions all around. We are getting some blowback, so we are thinking timing. We put a pressure guage on the fuel pump, so we know we have pressure and we are getting fuel into the carb. We've quadruple checked the wire order (actually, we recount them almost every other day) The issue with the starter is interesting. I just had the original starter rebuilt by a local guy who has a good reputation, but the engine does sound like it is laboring. It feels like it just needs a little more kick. We are tearing off the front end to make sure the gears are aligned properly. Thanks for the input. I'll update tomorrow after we get everything off if the weather cooperates.
    #9
  10. BuckeyeDemon

    BuckeyeDemon Member

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    1. Do you have a 351w firing order?

    2. Did you overtighten the rockers when adjusting causing the valves to be open?
    #10
  11. 68keyblr

    68keyblr Member

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    Even if timing was way off you'd be getting backfires through both intake and exhaust. Take a hard look at that starter, if it's the problem it will be due to internal resistance within the starter.

    Also, check #2 above from BuckeyeDemon - had that one happen too
    #11
  12. stevebr

    stevebr New Member

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    How do I check the starter? That is one thing we haven't tried,
    I tried rewiring for a 351 cam after talking to an old mustang guy in town and that got us a little closer it feels.
    I think the rockers are good, but again, how do I check to see if I overtightened them?
    Thanks for all the great ideas. Keep'em coming until this beauty runs for me.
    #12
  13. 68keyblr

    68keyblr Member

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    You can pull the starter and take it in to an auto parts store. They should be able to detect a bad starter with their equipment.

    Do you have good compression? If you pull the coil wire from the dist and hold it next to bare metal, what color is the spark? (careful with this one you can get a nice shock LOL) You should have a strong blue/white spark. if you have orange, that's your trouble

    As for the rockers, you can pull the distributor cap and turn the engine over until the rotor is right over the contact for a cylinder then readjust that rocker. I wouldn't go 1/2 turn past zero lash at this stage.

    I don't think your issue is firing order unless you are getting fire from only 4 of 8 cylinders and have a lot of backfires through carb.

    Simple stuff first - compression, spark, fuel.
    #13
  14. Hack

    Hack Active Member

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    Doesn't apply to stock Ford rockers. They just bolt down to a specific torque based on the fastener size. If you had adjustable height rockers you would know they could have been adjusted incorrectly.
    #14

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