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  • Chief_Alen
    replied
    Maybe installed 180 deg around !

    Leave a comment:


  • 2850Bounty
    replied
    Originally posted by builderdude View Post
    Come on, you've gotta have a few sbc’s just layin around?
    😂
    Perhaps several years back..... but not any longer, Dave.

    Leave a comment:


  • builderdude
    replied
    Originally posted by Hubcap View Post
    SUCCESS!!!!!
    I put the old cap and wires back on, left the new points, condenser and rotor in the replacement distributor and it fired right up.
    I did check that it had not jumped a tooth also.
    I guess new stuff does't always work the way it should. Only wasted about 8 hours of frustration but did learn a lot from all the replies and suggestions.

    Thank you to those who contributed.

    The big test will be tomorrow when I try to start it again since that's how the problem started, worked one day wouldn't start the next.

    Thanks again!
    Mike
    Bad cap or firing order was way off maybe. Glad you got her running again!
    👍🏼

    Leave a comment:


  • builderdude
    replied
    Originally posted by 2850Bounty View Post

    Dave, what if we both sit down together with some wooden blocks, paper and scissors, some crayons, a Gilberts Erector set, some string and pulleys, a Ken and Barbie protractor and degree wheel, two sharp pencils and sort this out?



    For those of you who may be surprised at that...... I'm only joking with Dave!
    Come on, you've gotta have a few sbc’s just layin around?
    😂

    Leave a comment:


  • 2850Bounty
    replied
    Good for you!

    Do not forget how important the correct progressive and total advance will be for these engines.
    Base advance is Base advance....... we fire up on it, and we idle on it.
    The more important aspect is what occurs above that as per engine RPM.


    .

    Leave a comment:


  • Hubcap
    replied
    SUCCESS!!!!!
    I put the old cap and wires back on, left the new points, condenser and rotor in the replacement distributor and it fired right up.
    I did check that it had not jumped a tooth also.
    I guess new stuff does't always work the way it should. Only wasted about 8 hours of frustration but did learn a lot from all the replies and suggestions.

    Thank you to those who contributed.

    The big test will be tomorrow when I try to start it again since that's how the problem started, worked one day wouldn't start the next.

    Thanks again!
    Mike

    Leave a comment:


  • builderdude
    commented on 's reply
    Oh man, Gonna be in my head all day now 😆

  • 2850Bounty
    replied
    Originally posted by builderdude View Post
    Rick, the way my brain works (and I'm not saying it works very good) I would physically and visually have to do it to an engine on a stand to confirm 🤔
    Dave, what if we both sit down together with some wooden blocks, paper and scissors, some crayons, a Gilberts Erector set, some string and pulleys, a Ken and Barbie protractor and degree wheel, two sharp pencils and sort this out?



    For those of you who may be surprised at that...... I'm only joking with Dave!

    Leave a comment:


  • builderdude
    replied
    Rick, the way my brain works (and I'm not saying it works very good) I would physically and visually have to do it to an engine on a stand to confirm 🤔
    Just for kicks I found these pics of old timing set vs aftermarket timing set. 22 toothed crank sprocket on my aftermarket set.


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  • 2850Bounty
    replied
    Originally posted by builderdude View Post

    Rick, if the chain jumped one tooth at the crank sprocket (18 toothed sprocket) would that not cause a 20 degree valve timming discrepancy?
    Im also wondering about the ignition advance statement. The ignition timing being related to crankshaft angle if in fact the chain jumped the ignition timing would follow the camshaft and also have a 20 degree discrepancy. Yes?🤔
    Yes... and also see my post #28 and my comment regarding how the spark timing would cause an engine to run (actually NOT run) if this occurred.
    This is where is gets difficult to explain and let alone understand. I even question myself every time I try to explain this!

    Keep in mind that the crankshaft and camshaft have a 2 to 1 relationship....... 2 Xs crankshaft per 1 Xs cam.


    ..... if the chain jumped one crankshaft sprocket tooth, it would cause a 20* change to the position and location of the chain.
    (360 divided by 18 = 20)
    In other words, the camshaft chain sprocket would either lag behind, or lead the crankshaft by 20*

    ..... if the chain jumped one camshaft sprocket tooth, it would cause a 10* change to the position and location of the chain.
    (360 divided by 36 = 10)
    In other words, and with the 2:1 ratio, the crankshaft chain sprocket would cause the camshaft to either lag behind, or lead the crankshaft by that same 20*.

    If I'm mistaken, please point it out. I'm old and my mind is not what it used to be. And no making fun of me!!!!



    Click image for larger version  Name:	SBC timing chain and sprockets.jpg Views:	1 Size:	87.7 KB ID:	554332

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  • 2850Bounty
    replied

    Originally posted by Rick
    Since ignition advance relates to crankshaft angle, and is adjusted in crankshaft degrees, the ignition advance would NOT also be off by 10* .
    Originally posted by Jim_Gandee View Post

    Rick, I barely know what a piston is but since the distributor is driven by the cam wouldn’t the timing therefore be off if the timing chain slipped one tooth? Maybe I’m misunderstanding your comment?
    Well, good question Jim, and it would require me to give a two part answer/explanation.

    1.... if the chain jumped one sprocket tooth, and if the ignition advance had been adjusted after that occurred, then the answer would be NO..... the timing would or could still be spot on.

    2....if the chain jumped one sprocket tooth, and if nothing since then had been done to the ignition advance, then yes.... the ignition advance would also be OFF to the tune of 20 crankshaft degrees.

    We all know that an engine would not run if the ignition advance was off by 20 crankshaft degrees.
    It would not start up on 18*, and it would detonate on 38* @ 3k rpm.





    Leave a comment:


  • builderdude
    replied
    Originally posted by 2850Bounty View Post
    ......................

    If a timing chain was to jump one tooth at either sprocket, it would equate to a 10* change at the camshaft.
    (360 degrees divided by 36 = 10)

    Keep in mind that all indexing (cam, piston TDC, etc) is done in terms of crankshaft angle.


    [COLOR=#0000FF]Since ignition advance relates to crankshaft angle, and is adjusted in crankshaft degrees, the ignition advance would NOT also be off by 10* .

    .
    Rick, if the chain jumped one tooth at the crank sprocket (18 toothed sprocket) would that not cause a 20 degree valve timming discrepancy?
    Im also wondering about the ignition advance statement. The ignition timing being related to crankshaft angle if in fact the chain jumped the ignition timing would follow the camshaft and also have a 20 degree discrepancy. Yes?🤔

    Leave a comment:


  • Jim_Gandee
    replied
    Since ignition advance relates to crankshaft angle, and is adjusted in crankshaft degrees, the ignition advance would NOT also be off by 10* .

    Rick, I barely know what a piston is but since the distributor is driven by the cam wouldn’t the timing therefore be off if the timing chain slipped one tooth? Maybe I’m misunderstanding your comment?

    Leave a comment:


  • 2850Bounty
    replied
    ......................
    Originally posted by Hubcap View Post
    Well...



    Still no success, although i do have proper dwell now.
    What did you do about the distributor shaft side play that you mentioned earlier?
    What dwell angle did you use?


    Could the timing chain have slipped?
    It would be very rare for this to have occurred.

    How does one check to see if this is the case without having to remove the front engine parts?
    See Dave's response below.
    Originally posted by Dave
    You can use a crank wrench to roll the crank back and forth while watching the distributors rotor, if it takes a bit of crank movement in the opposite direction before you see the rotor react that’d be an indication of the amount of slop that’s in the chain.

    Originally posted by Hubcap View Post
    I did compression check on nbr 1 only it was 155 psi. I will do them all tomorrow but since # one is at 155 wouldn't that indicate things are good?
    155 psi is within a good range for this engine.
    If all cylinders are within 10% of the highest cylinder pressure reading (what ever that reading might be), all would be within a safe range.


    Side note:
    Ideally we want the rotor to be aiming towards the #1 cylinder while #1 is at TDC on the C/S.
    However, as long as the spark plug cables are indexed correctly within the cap, and are following the firing order, this is not critical......... the engine will operate just fine!



    Originally posted by Hubcap
    Is it possible the neutral safety switch could be affecting the starting even though the engine is turning over normally?
    Unlikely. The Neutral Safety switch (while not in neutral) interrupts the starter motor's S circuit ONLY.

    Does it by chance act similar to a kill switch by grounding the ignition out?
    A lanyard style kill switch (when the lanyard clip is pulled from the switch) interrupts the Ignition circuit only.
    It does not take the circuit to Negative!


    NOTE: if your alternator field circuit is supplied by the ignition circuit, you could undergo alternator damage if a kill switch clip was pulled while running.
    (it's unlikely that your AQ225 is equipped with a lanyard style kill switch as per the above)


    If a timing chain was to jump one tooth at either sprocket, it would equate to a 10* change at the camshaft.
    (360 degrees divided by 36 = 10)

    Keep in mind that all indexing (cam, piston TDC, etc) is done in terms of crankshaft angle.


    Since ignition advance relates to crankshaft angle, and is adjusted in crankshaft degrees, the ignition advance would NOT also be off by 10* .

    Click image for larger version  Name:	SBC timing chain and sprockets.jpg Views:	0 Size:	63.9 KB ID:	554290




    Originally posted by Dave
    Based on your findings regarding the distributor shaft play and chewed up cap/rotor issue I think you should investigate the possibility of an ignition issue further. Have you verified a good snap/spark at the plugs?
    I agree 100%.

    Excessive side play (within the distributor shaft) will prevent you from setting the correct dwell angle.
    Once up and running, the dwell angle will be erratic.

    You should be seeing a white or bluish/white spark, and should be able to hear is snap.




    .

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  • builderdude
    replied
    Based on your findings regarding the distributor shaft play and chewed up cap/rotor issue I think you should investigate the possibility of an ignition issue further. Have you verified a good snap/spark at the plugs?

    Leave a comment:

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