383 misfire

Newport 66

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I've got a issue with one of my 383's. I rebuilt the carb, replaced the plugs and wires and now I have a misfire. Ran a compression check. All cylinders are in the 125 range. Looked at the plugs and 7 of the 8 were firing and tan colored. # 7 looks like it just came out of the box, not firing at all. I thought bad plug, nope. Bad wire, nope. Not wanting to be a parts chaser. Could it be a bad distributor cap?
 

mr gtx

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7 has to be firing else it would be black and not white. did you check your wires are in the right firing order
 

thethee

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X2 on the firing order. Seems unlikely that a carb problem affects a single cilinder. If the problem arose after plugs and wires replacement would suggest cause has to do with those.
 

Newport 66

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Ok, this is getting strange. New plugs and wires. Double checked the firing order and distributor is rotating. Car won't start now. Backfires thru the carb. I'm thinking now it jumped time. Had to quite for the day so I'll confirm tomorrow.
 

Rustyrodknocker

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Ok, this is getting strange. New plugs and wires. Double checked the firing order and distributor is rotating. Car won't start now. Backfires thru the carb. I'm thinking now it jumped time. Had to quite for the day so I'll confirm tomorrow.

If you still have your factory nylon tooth cam gear it may have just shucked a few teeth.
Rotate you engine to top dead center compression stroke on number one cylinder and see if the rotor is pointing at the no.1 terminal or slightly past.
 

57fury440

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How did it run before you changed anything? I would still check the firing order, the direction of the rotor and all the wires.
 

Newport 66

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If you still have your factory nylon tooth cam gear it may have just shucked a few teeth.
Rotate you engine to top dead center compression stroke on number one cylinder and see if the rotor is pointing at the no.1 terminal or slightly past.
Yes sir, I'll do that in the morning.
 

Big_John

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Ok, this is getting strange. New plugs and wires. Double checked the firing order and distributor is rotating. Car won't start now. Backfires thru the carb. I'm thinking now it jumped time. Had to quite for the day so I'll confirm tomorrow.
Did you by any chance, pull the distributor out between having it running and it now not running?
 

1970cat

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put the non-firing plug in another cylinder to check if is faulty.
 

thethee

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If you still have your factory nylon tooth cam gear it may have just shucked a few teeth.
Rotate you engine to top dead center compression stroke on number one cylinder and see if the rotor is pointing at the no.1 terminal or slightly past.
In addition to this you can rotate the engine back and forth while checking when the rotor starts moving. If it takes a while for the rotor to move there is probably enough slack in the timing chain for it to have jumped a tooth, confirming your suspicion.
 

CBODY67

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IF the timing has jumped, starting will be difficult and even have some flaming spitbacks, as it turns over. To verify, you can advance the timing one full plug wire's rotation advanced. If it starts easier and no spitbacks, that can be confirmation. Saw that "advance the distributor one notch" work as the old-line Chrysler service manager diagnosed a TX DPS car back in 1976 or so, at the local Chry dealership.

When my '80 Newport's timing chain failed, it had been running a bit funky for a day or so prior. No tuning would help it, so I suspected it might have been the computer, but it was not (after I swapped in a new Chry reman unit). Then, when driving, I slowed to make a u-turn and it died and would not restart.

One reason I consider ANY OEM timing sproket with over 80K miles on it "on borrowed time". Even if the engine might be running nicely, it's just a matter of time before you might be stranded somewhere, hopefully with cell service. Especially if the car pre-dates about 1990s, fwiw.

Just some thoughts,
CBODY67
 

1970FuryConv

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Important advice above: I had about 130000 miles on a 1973 Dodge Monaco, 400/727. The nylon teeth on the cam sprocket disintegrated over the course of about a mile and left me stranded at night. Cleaning all those pieces of nylon teeth out of the oil pan added significant time to the repair.

I had no misfire or any other warning. The misfire might be good luck.
 
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