[B]How To Set Timing?[/B]

Discussion in 'General IH Tech' started by joncor, Aug 6, 2006.


  1. joncor

    joncor Farmall Cub

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    I know I'll prob catch all kinds of "search the forum" heck for this question but I did a quick search and did not find the elementals of setting timing. I am trying installing the distributor off of a '79 Scout ll 345 that I have for parts into my '78 Scout ll 345 before getting a rebuilt one (mine is bad) and would like to do the timing myself. I bought a timing light but have never done it before. I know that you hook it up to the #8 spark plug wire but I dont know where exactly you point the flashing light, what you are looking for and what the different timing figures mean like TDC (true dead center) or 5B which I see in my book. Also it seems that these figures are distributor specific and not vehicle specific. Does that mean that I go by the distributor # and set the timing to that specific distributor?

    Thanks for any help

    Jon
     
  2. jeff campbell

    jeff campbell Lives in an IH Dealership

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    find the sticker on your truck,hood,above the radiator?go by what it say's on there,the timing indicator is above the bottom pully an behind a bit an off to the side.,clean it off real good.,anplug the vaccum advance hose,then set it.jeff
     
  3. rusty

    rusty Binder Driver

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    I'll take a stab. Im sure some of the gurus will chime in as well and fill in any blanks I missed.

    Setting the timing means that the distributor fires the #8 cylinder plug when the #8 piston is at the very top of it's compression stroke. (well, they'll ALL fire at the very top, but the timing marks on the front of the engine are setup so you can check #8).

    TDC is when the piston is at the very top of the compression stroke. Factory specs are to set it so #8 fires at 0 degrees ,TDC. Most folks recommend setting the final timing around 6 degrees BEFORE TDC. This means the plug fires while the piston is still moving up in it's compression stroke. Mine runs pretty good there as well. Once you get the hang of it you can play around with where it runs best with a load or up a hill (eg if it pings under a load try setting it a few degrees before tdc and wash, rinse, repeat as needed).

    If you took the distributor out and didn't mark the location of the rotor you'll need to set initial timing so that the engine is fireing #8 somewhere near TDC.

    If you haven't removed the old distributor yet, then rotate the engine with a wrench until the rotor is pointing at the #8 wire on the cap AND the timing mark on the pully is lined up near the 0 mark on the degree ring (see below for details). Remove the cap only and mark where the roter is pointing. When you put the new distributor in make SURE the rotor is pointing in the same position as the one you took out then move to the steps for final timing.

    Initial Timing: (meaning you've taken the distributor out but have no idea what position the engine is in then you have to get #8 at TDC):

    To locate TDC for the #8 cylinder: The #8 cylinder is the farthest rear on the passenger side. Pull all the plugs and have someone rotate the engine with a wrench on the harmonic balancer (it's the big pulley at the bottom front of the engine that's bolted to the crankshaft). It also has a line scored across it that marks the #8 piston position.

    Clean up this area on the balancer and mark it with some white paint so it's easy to see. Make sure you only get white in the score line. I've used Whiteout before, just clean it up, paint it across the mark, then wipe it off so that the only remaining paint is IN the groove.

    Just above the harmonic balancer is the timing degree marks. Clean up this area so you can see the marks on the degree ring. One of them (the 2nd to the last one in the rotation direction IIRC) is marked with a 0. That's 0 degrees (TDC) in the circle that the crank makes.

    When your buddy turns the engine, as the mark on the balancer approaches the timing marks on the degree ring stick your thumb/finger/compression guage in the #8 spark plug hole. make sure you get a good seal. when you feel compression (air trying to push your thumb out) that's the compression stroke. continue turning the crank slowly until the mark on the balancer lines up with the 0 mark on the degree ring.

    Your #8 piston is now at TDC (as high as it will go in the cylinder of the COMPRESSION stroke). Turning it any further (the mark PAST the 0 degree mark) and the piston is on it's way back down on the POWER stroke.

    Now you can put your distributor in. DO NOT DROP ANYTHING DOWN THAT HOLE. Make sure that you line up the rotor in the position that will point to #8 on the distributor cap. snug up the clamp and double-check that your spark plug wires on the cap correspond with the firing order and that the rotor is pointed at the #8 wire on the cap.

    Firing order is 8-4-3-6-5-7-2-1

    (also a good addendum http://www.binderplanet.com/faq/5.htm#20 and http://www.binderplanet.com/faq/5.htm#11)

    Put your plugs back in and triple check the firing order and put the cap back on and triple check that the rotor is pointed at #8 on the cap.

    It should start and run like crap cause you can't get the rotor pointed EXACTLY at #8.

    Final timing:

    Clear away all tools and whatnot. Remove the vacum advance tube from the base of the carb/intake to the distributor. Plug the port so it's not sucking air.

    Hook up the timing lite and start the engine. Keep timing lite leads clear of moving parts! From the passenger side standing by the hood prop, Point the lite down past your ac compressor/alternator and you should see the white mark on the balancer somewhere near the 0 degree mark on the degree ring.

    If you don't see the mark then it's probably backfiring like mad and you've done something wrong so re-do all steps.

    If the mark is near the 0 degree mark then stop the engine and loosen the distributor clamp till you can turn the distributor fairly easily but not to the point that it's REAL easy.

    Start the engine.

    Point the light down at the timing mark and pull the trigger.

    Rotate the distributor SLOWLY. You should see the timing mark on the balancer move in relation to the 0 degree mark on the degree wheel. Move the distributor around till the mark is lined up with the 0 mark.

    If you can't get the mark near 0 by rotating the distributor just a little bit then you'll need to set #8 at TDC again, pull the distributor and try harder to get the rotor pointed at where the #8 plug wire is on the cap.

    Set the idle mixture on the carb. check the timing again. repeat until idle and timing are good.

    Reconnect vacum advance and set idle mixture and timing again.

    Once all is well, make sure you tighten the clamp on the distributor. (yes, I forgot to do that once :eek: )
     
  4. joncor

    joncor Farmall Cub

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    Thanks Rusty and Jeff

    Rusty, that was an excellent explanation. I think I finally got it from here. Fortunately I knew about marking the rotor position and putting the new one in the same spot but only because I did'nt know it and put the thang in any ole way once years ago! It did'nt run so well :D.

    Thanks Again

    Jon
     
  5. jeff campbell

    jeff campbell Lives in an IH Dealership

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    just make sure you have a GOOD dist.,cap an rotor on it,if the cap electrodes inside,have buildup on them ,an you scrapem off,it won't run all that well,jeff,but it will run ok.?
     

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