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Spark and coil lead resistance readings

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Matt G:
Hi guys, Does anyone have a 'typical' and 'bad limit' ohm reading for my spark leads and for my main coil lead (if different). I've had some issue with missing and spluttering when warmed up recently (it's a fight to keep it running at lights and misses badly at loaded and unloaded higher revs). My distributor cap was filthy, and had some moisture residue. It's all cleaned up now, but thought that I'd check the leads for issues while I'm at it.
Any info/experience would be great.

Vettech:
Obviously an older kettering system style car (C1,2,3).

Lots of issues. Are leads solid wire or resistive type. Solid = 0ohms, resistive = very high (meg ohms).

Try running up to temp at night, lift the hood in the dark and check for crossfire, arcing, breakdown.
Will appear as blueish crackles and flashes. Look at plugs if one is lightup or flashing, it maybe damaged internally.

I usually change Plugs, leads, points, cap ........AND the capacitor/condensor in the dissy.

If still faulty, only one thing left, the Coil, now you may also have a dropping resistor, which is by-passed when starting (gives full 12v hotter spark).
Comes into cct to drop volts to coil when running, as coil is designed to run extended periods at lower volts therefore cooler etc etc.

It is not unusual in electrical car ccts for heating to come into play after a time, any component can get hot enough to expand a crack or joint
and give an intermittent HR. This type of fault is the bane of the auto-electrician.

BOB

Vettech:
Sorry - another thought, is the timing ok?...

Matt G:
Thanks Bob, lots to look into.  Thanks.  Yes C3 (70), but not standard ignition (previous owner's choice).  No points, MSD Ignition (6AL I think - need to check), Accel 8.8 Silicone leads with spiral core.  Accel Coil as well. I had planned to pull leads, to check for changes in idle, etc, which I think would give the same result?  I'm guessing that the blue arc is around the cap join to the spark plug/distributor cap, or do you mean along the lead length as well?  I remember running solid copper cables on Dad's old Datsun 120Y... Made a HUGE difference in power (which still wasn't that much), but it also killed the radio signal :).
I've dropped a cylinder previously via a burnt through spark lead, and it was more of a consistent power down experience.  This feels like multiple cylinders at once (2 to 3), so i went straight for the cap, and figured that I'd work towards the coil and the ignition box.  Timing is a little too advanced, but I don't think that's my problem.  I need to check it again anyway.  I haven't gone for a spin since I cleaned the cap, so maybe I should do that also... ;P
I found an NGK site that indicated between 1 and 6 kilo Ohms.  I checked a couple earlier this morning and got 1.35 and 1.7, so maybe all good...
How do you test a coil?

bfit:
Go back to basics ,  be prepaired with tools etc take that car out for a drive  when it starts to play up turn engine off and coast to a safe place and pull all the plugs. They will tell you a story .
Bfit

PB crap look down

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