413 Diagnostics Help

[al_wildman]

I really feel like a fool asking a question that is so open-ended, but here goes: I have a 1962 Sport Fury with a V code 413 (V code means it's a 1964 engine). It has a mild build with what sounds like a purple hydraulic cam; heads that are one step down from max wedge, with dual valve springs; two Edelbrock 600s on a Weiand high-rise; Pertronix ignition; headers; etc. Motor has always run strong, but recently started running really rotten and backfiring through the exhaust. Car does not have an operational fuel gauge, so my wife and I ran slam out of gas coming home from a car show right when the backfiring and rotten running started. I mention this because, once I limped the car home, I upgraded the fuel delivery with a new Edelbrock high volume-low pressure mechanical pump, 5/16 lines all the way back, including the pick-up/sender unit. I also took the air horns off the carbs and cleaned and blew out the passages, the best I could without removing the carbs. None of this helped. I replaced the coil (Accel 140001) this morning, hoping for an easy resolution. No such luck. Same as before. I talked to the Pertronix troubleshooter some time ago and he said that is not how they fail. They normally work fine or not at all. Distributor cap, wires, plugs are all as new. I have not checked fuel flow directly. I don't have access to an engine analyzer, etc, only a timing light and dwell meter. Sounds like an ignition issue, I guess. WHAT WOULD YOU CHECK NEXT? Thanks very much, in advance, for your advice.

 

[al_wildman]

I really feel like a fool asking a question that is so open-ended, but here goes: I have a 1962 Sport Fury with a V code 413 (V code means it's a 1964 engine). It has a mild build with what sounds like a purple hydraulic cam; heads that are one step down from max wedge, with dual valve springs; two Edelbrock 600s on a Weiand high-rise; Pertronix ignition; headers; etc. Motor has always run strong, but recently started running really rotten and backfiring through the exhaust. Car does not have an operational fuel gauge, so my wife and I ran slam out of gas coming home from a car show right when the backfiring and rotten running started. I mention this because, once I limped the car home, I upgraded the fuel delivery with a new Edelbrock high volume-low pressure mechanical pump, 5/16 lines all the way back, including the pick-up/sender unit. I also took the air horns off the carbs and cleaned and blew out the passages, the best I could without removing the carbs. None of this helped. I replaced the coil (Accel 140001) this morning, hoping for an easy resolution. No such luck. Same as before. I talked to the Pertronix troubleshooter some time ago and he said that is not how they fail. They normally work fine or not at all. Distributor cap, wires, plugs are all as new. I have not checked fuel flow directly. I don't have access to an engine analyzer, etc, only a timing light and dwell meter. Sounds like an ignition issue, I guess. WHAT WOULD YOU CHECK NEXT? Thanks very much, in advance, for your advice.

View attachment 840360

Car has power brakes, but I have tried blocking the vacuum line to make sure no gross vacuum leak exists in the brake booster. Again, no help

 

[black64]

How is your fuel tank any junk in the tank? Check fuel filter maybe picked up crud from bottom of tank when your fuel was low. Might want to check sock filter in the tank also. Problem started when you were low on fuel.

 

[oldbee]

Water in gas, carbon-tracking in dist cap?

 

[Don Frelier]

Start with the basics:
Compression (Do a compression test)
Fuel - (To clean the carbs completely you really need to take them off the car)
Spark - Pull off the coil wire and hold about 1/4" away from a good ground should be blue and crisp not yellow and lazy.
Then consider Valve and Spark timing.
Maybe cam lobes wiped? Push rod broke?
With solid state ignition timing should not change unless your chain jumped.

 

[khryslerkid]

You're not useing a condenser are you? If so replace it. (You mentioned a dwell meter and also Pertronix)

 

[PRND21]

My first thought is if this started when you ran it out of gas that you picked up some crap from the bottom of your tank. Check your fuel filter, I’d guess you have dirt/rust/crud in your carbs. Ethanol in the gas attracts moisture and rust in your tank.

 

[al_wildman]

My first thought is if this started when you ran it out of gas that you picked up some crap from the bottom of your tank. Check your fuel filter, I’d guess you have dirt/rust/crud in your carbs. Ethanol in the gas attracts moisture and rust in your tank.

I drained the tank. No evidence of water or crud. Sock in tank was replaced with pickup/sender unit and line filter by pump is new.

 

[al_wildman]

You're not useing a condenser are you? If so replace it. (You mentioned a dwell meter and also Pertronix)

No condenser

 

[al_wildman]

Water in gas, carbon-tracking in dist cap?

No contamination when I drained tank. Cap is new and clean,

 

[PRND21]

I drained the tank. No evidence of water or crud. Sock in tank was replaced with pickup/sender unit and line filter by pump is new.

Well if you don’t find anything else, I think I’d pull the carb tops just to make sure that they’re clean. Other things that can cause backfiring is cam timing, ignition timing/firing order. As Don said, check your basics.

 

[Moparnocar]

What does dwell look like? Steady? I never have trusted those points conversions, had one go bad and die. I swear it ran bad first, but I could be wrong

 

[miller]

Ethanol in the gas attracts moisture and rust in your tank.

Also consider what fuel line rubber hoses your using. Ethanol will eat the insides of regular fuel hose. Recommended to only use Gates fuel injection hose, that holds up to ethanol.
You can tell, if you pull the carb tops, to look in the bowls. Blackish powder, that will clog the carbs.