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1966 Coupe-289-3sp-No A/C
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Discussion Starter · #1 ·
New motor Build 302 (1973), bored 30 over, aluminum heads 500 springs, 100 closed-280 open, 60cc, aluminum piston's, Edelbrock 600 carb, headers, Lunate Cam (#10350701LK) and lifters, roller rockers,
Here is the deal, with NEW plugs it starts up and within a few seconds its running smooth and clean as you could ask for-vacuum gauge is dead steady at 18, timing set with Vac gauge because I don't have ability to use light No timing marks (truck block), take off and runs strong and smooth and about 2-3 miles you feel a little miss starting and it goes down hill quick, hurry and get back to house by then all 8 plugs are Black soot like you sprayed black primar on them-been thru 5 sets of plugs, I just don't know what to check next, been 2 weeks on this, nothing seems to change anything, about 120 comp on all, did test cold and only 1 plug at time, don't think the rings can even be seated yet,Mallory Dizzy
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any help appreciated.
 

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Black/brown smoke is usually fuel. Blue smoke is oil. I'd look for a carb problem. I'd look for a choke problem first. If you see fuel spilled onto the intake manifold, check for a sticky float or needle.
 

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1966 Coupe-289-3sp-No A/C
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Discussion Starter · #4 ·
Black/brown smoke is usually fuel. Blue smoke is oil. I'd look for a carb problem. I'd look for a choke problem first. If you see fuel spilled onto the intake manifold, check for a sticky float or needle.
Have choke wired open just to cover every base and carb is 6 months old, ran perfect on old 289, and adjusts properly with vacuum gauge, also tried another carb (Holley 600 new) and no difference.
 

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You have to get a timing light on it. But it sounds like a fuel problem. What is your fuel pressure?
 

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Possibly a bad or missing engine to chassis ground. Had a very similar problem many moons ago that would do the same thing.

Could also be the module in the Mallory Unilite distributor going bad.
 
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Discussion Starter · #10 ·
You have to get a timing light on it. But it sounds like a fuel problem. What is your fuel pressure?
I stated there is no timing mark as block was a truck block with the timming on passenger side I changed waterpump to passenger side so there is NO timing light marker, I'm setting timming with vacuum gauge and old fashion when its smoothest.
 

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Sounds like ignition break-down. Is the alternator charging? Coil overheating? Looks like you have 2 taps on your coil+ (solid-state distributor module).... Is your resistor wire still in place? That would mean low-voltage to the module. If the resistor wire is bypassed, that would mean too MUCH voltage to your coil.
 

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Discussion Starter · #17 ·
Sounds like ignition break-down. Is the alternator charging? Coil overheating? Looks like you have 2 taps on your coil+ (solid-state distributor module).... Is your resistor wire still in place? That would mean low-voltage to the module. If the resistor wire is bypassed, that would mean too MUCH voltage to your coil.
yes new 100 amp alt, charging 14.67v, risistor wire still in place, was told thats how this Mallory worked same as original?? took out points dizzy thinking it was not working right, I've been thinking coil breaking down when hot, but don't know how to confirm this..Thanks
 

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Discussion Starter · #18 ·
yes new 100 amp alt, charging 14.67v, risistor wire still in place, was told thats how this Mallory worked same as original?? took out points dizzy thinking it was not working right, I've been thinking coil breaking down when hot, but don't know how to confirm this..Thanks
have 6.2volts at coil +, is that not correct for this Mallory Unilite????
 

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If you let it idle for say 20 -30 mins and check the plugs. If they foul, probably a rich mixture. If they are normal, I'd look at timing and if the dizzy is advancing etc...
 
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