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L18 timing and vacuum advance question


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My dime has a L18 in it with a pertronix ignitor in the distributor. it idles fine and runs good at high RPMs but when you slowly press the gas it makes a sucking noise and sputters and will die if I don't give it more gas. if I drive it pedal to the floor all the time its OK. so i tried to adjust the timing, disconnected the vacuum advance, hooked up my timing light, and the mark on the crank pulley is like 4+" away from the TDC mark. I cant turn the distributor enough to get any closer. I have a light with an advance and I turned the knob 60 deg. advanced and the marks were still a few inches away. Is my vacuum advance stuck? Can the crank pulley be installed 180 deg. off? Is this related to my throttle problem? Thanks

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Start with this.



  1. Use a bright colored marker/paint to mark the timing mark on the harmonic balancer to make it easier to see.
  2. Let the engine idle until warm and loosen your distributor hold down to adjust your timing at idle to the factory specs.
  3. Turn off the engine, pull the distributor cap, and get a short piece of CLEAN vacuum line to put on the vac advance and suck to watch for it to move. If it doesn't, it's either stuck or the diaphragm is leaking.
  4. Do whatever datzenmike tells you to do after this tongue.gif

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already marked the timing mark on the balancer. warmed up and loosened the distributor to set timing at idle but i cant turn the distributor far enough to get the marks even close, the balancer mark is down at 6o clock and my timing mark on the front cover is around 2 oclock. I will try the suck test on the advance and see if it moves. Thanks!

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I think my L18 has the timing scale at about 2:00. So that sounds about right. The pulley notch is down at the bottom 6:00????? Maybe the pulley or the distributor was swapped.


Turn the distributor until you get the fastest smooth idle then turn the distributor counter clockwise slightly and drive it with heavy throttle. Advance it slightly more and drive again. Keep going until it pings under load. Back it up (retard) just enough to run with hardly any or no pinging. Timing is set, ignore the timing scale and marks.

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the pulley goes on only one way as the due to the wedge pin that lines it up.


what have you donbe befoe this happen.?


Is this dizzy the org before you put the Pertronix on there. or its another dizzy that would fit a Pertronix then you mounted it to the old dizzy plate that goes to the front cover?


turn motor to TDC and youll be able to figure this out unless you hooked up the timming light to #4 or something.

I have seen different pulleys installed that have the mark in the wrong spot.


also on the underside of the dizzy is a 8mm bolt that you can loosen to get the dizzy to turn a little more in the direction you need if possible.

also if oil pump was dropped maybe you lined up the spindal off one tooth. but usually it kills the high end.


this is a simple fix



maybe you main jet is plugged ?



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Thanks for the advice guys. I bought the car like this, used the dizzy that came with the car for the pertronix install, and with both adjustment bolts loose i still can't get the marks even close. The whole car was rebuilt probably in the 80's so who knows what mismash of parts it has. I have a feeling that the pulley was swapped and the mark is wrong. I already watched your awesome video hainz and I'm just going to take off the cam cover and set TDC from the timing gear notch, and put a new mark on the crank pulley. That should solve it, Right?:blink:

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