2 days ago in News
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Ok, so I picked up a solid little Falcon a few weeks back. Fresh engine rebuild, but not running right...had trouble holding an idle and no power whatsoever. Would eeek its way up to about 20mph then stall, but fire right back up when I coasted to a stop.
After doing basic tune-up things, I found it had the original Load-O-Matic distributor, but not the correct carb matched to it. Figuring that a wonky vacuum advance signal could definitely cause similar issues, I ordered the correct vac/mechanical advance distributor and put in a Pertronix module. Now I cant get it to fire off.
A few things of note:
I've got spark, I've got fuel... any thoughts on where else to look? I'm a bit stumped.
Just to double-check, 12V to the distributor gets a bullet point and then the summary says spark; just wanted to make sure that you've seen spark at a plug, and that you're not assuming things are good from there...
Have a timing light so you can verify that the spark is happening at a reasonable time?
With the installation of new distributor and new electronic ignition, that makes the likelihood of timing being off or of the electronic ignition not doing its thing correctly the most obvious possible culprits to me. Verify Pertronix wiring?
And similarly you've-probably-already-checked, but double-check that you've got the wires on the new distributor cap in the correct firing order?
Points dizzys had a resistor in the power to the dizzy. See if they wired to original power or measure voltage there. Eliminate the resistor or find another source.
edit: oops, seen ya got 12v to dizzy.
In reply to Ransom:
Yeah, good observation. I do have spark at the plug (#1 at least, have not pulled and checked all six). I guess the 12v bullet point was just an observation that the Pertronix module is getting the constant 12v it needs.
Plug order is correct and matched to the firing order (1-5-3-6-2-4). Excellent thoughts, keep 'em coming gents!
You have spark and fuel.
That leaves compression and timing.
Double check you aren't 180* off on the timing.
Other thought is to run the valves. Yo assumed ignition was the problem and changed parts. But I've seen way outta wack valve adjustment do similar things.
Noted, and thanks for all the suggestions. I have confirmed that I am not 180* off on engine timing - I'm starting at the top of the compression stroke - confirmed by valves and pulling the #1 plug to check for compression.
Here's the weird thing: The distributor is a newly rebuilt unit. To rule out the electric ignition module, I threw the points back in it.
When I align the rotor with the #1 terminal (or really any terminal - the dist cap is indexed to only go on one way) I would expect the points to be open, allowing a spark to hit the #1 plug. The points are indeed closed at this point though, with the wiper sitting dead in the middle of a flat on the distributor cam. There's no way for the points to be open when the rotor is pointed at a cylinder on the distributor cap.
Contrast that with the old distributor - the peaks of the cam align with the index mark for the rotor as I would expect.
What am I missing? I know I can rotate the dist once it's installed, but that doesnt seem to alleviate the issue because the distributor cap rotates at the same time. Is there a variable i am missing?
Do remember that to account for added advance, you want the one edge or the other (can't recall) of the rotor under the #1 terminal when timing it static, sounds like maybe you are on the wrong edge? A timing light and degree tape on the balancer might come in handy at this point.
Can you take off the cam (there's a clip in the center hole with the grease) and reinstall it 180° from where it is now?
@Ransom: I just read your signature quote. I always heard that as, "I'm looking for the dope with a microscope."
Have you put a timing light on it yet? Initial timing advance should not be 0 degrees as described above. Should be 4 to 12 degrees initial advance. With vacuum advance hooked up it may be as much as 35 degrees advanced.
Do you have a 144, 200, 250 6 cylinder and what year and transmission?
I could be missing something here, but have to ask. Has it run properly since the rebuild? It sounds like you may be a couple of teeth off on your timing chain to me.
I have not thrown on a timing light or degree tape yet, as the dampers on these engines are notorious for slipping (two piece design with bonded rubber). I did add a new mark on the pulley to indicate where #1 is visually at TDC when looking through the spark plug hole.
It's a 200 - out of a 67 Fairlane according to the previous owner.
I do agree that the rotor should be just a touch past the #1 cap terminal at TDC, but the cam loves seem to be a good 15 degrees or so off from where I would expect.
I did not perform the rebuild work - I may need to pull the timing cover and take a look, but was hoping to avoid it if possible.
How is the condenser? Did you replace it. If it is shorted it will do weird things.
To check cam/crank timing, find #1 TDC, and wiggle the #1 valves. Tight? Rotate 180degrees. Still tight? Out of time. Maybe look down the #1 spark plug hole, or use a do well or something to confirm TDC as best you can. It doesn't have to be perfect.
Completely independent of the engine itself, I still feel there's something off inside the distributor. See the pictures above.
There's an index on the dist shaft for the rotor, and a notch in the distributor body indicating the position of the #1 plug on the cap. When these are aligned, the wiper block on the points is lying directly in the center of a flat spot on the cam (points closed). There's no way I see that would allow the points to be open when the rotor is aligned with a terminal on the cap.
Am I wrong to expect the distributor cam lobes to correspond better with the rotor position?
I can see what you are getting at with the distributor, but it is hard to get s clear idea over the inter webs. Not to oversimplify, but once installed, couldn't the body of the distributor be moved to allow the points to open at the proper time? Maybe I'm missing something, but my gut tells me these engines will let the body swing a mighty long way. More than the 60 degrees needed to get there.
Another question: could the oil pump drive need to be turned to get the gears to mesh better? It has been a long time since I've laid hands on one of these beasts. I hope I'm helpful rather than confounding.
Have you checked the compression?
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