stock 348 dies after running for ~1/2 hour

[Lt.FrankDrebin]

This started happening fairly recently each and every time I run the engine. My stock 348 dies after running for about 1/2 an hour. This time, I monitored the temperature with a thermometer. Upper radiator hose and top of radiator is about 160 degrees, upper engine is about 165 degrees, and the center carb is about 135 degrees. There is still spark after it dies. In fact, I replaced the points, dist cap, and rotor and set dwell and idle speed recently, thinking the problem was in the ignition system. What would you guys suspect?

 

[64ss409]

Is your gas cap vented?

 

[Jim Sullivan]

This started happening fairly recently each and every time I run the engine. My stock 348 dies after running for about 1/2 an hour. This time, I monitored the temperature with a thermometer. Upper radiator hose and top of radiator is about 160 degrees, upper engine is about 165 degrees, and the center carb is about 135 degrees. There is still spark after it dies. In fact, I replaced the points, dist cap, and rotor and set dwell and idle speed recently, thinking the problem was in the ignition system. What would you guys suspect?

I’m guessing you replaced the condenser with the points. If not, you probably should as it sounds like an issue I had several years ago, with a bad condenser.

 

[Lt.FrankDrebin]

Is your gas cap vented?

Gas cap is not vented, but a '58 gas tank itself is vented, right? I guess I could pull the gas cap off when the engine starts to die to see if there is a sudden resurgence? That would confirm that there is negative pressure building up in the tank.

 

[Lt.FrankDrebin]

I’m guessing you replaced the condenser with the points. If not, you probably should as it sounds like an issue I had several years ago, with a bad condenser.

Yes; condenser was replaced along with points. Still behaving like this after rotor/cap/points/condenser replacement. I'm still getting a strong spark after the engine dies.

 

[Jeffrey Osstyn]

Not that this is your problem, but new parts for point ignition systems are always suspect. Unless you find some original Delco stuff or other bygone aftermarket parts. Condensers especially are suspect, original ones can go bad just sitting on the shelf, and the 'new' ones, are junk right out of the box! Take one apart sometime and see how crappy they are.

 

[rsavage]

I would have suggested coil but you still have good spark. If you have spark, and it is not hot enough to have vapor lock, could your fuel pump be losing its pumping ability after running awhile? Will it start right back up or does it have to cool down? Are you running a resistor block?

 

[Don Jacks]

The 58 cars and trucks used a vented gas cap.Remov cap,drive car and see if the symtoms reaccure.

 

[Barry Taylor]

Did the 58 models have the sock on the fuel pick up! If so that could be sucking up rust flakes and shutting it down! Had this happen to me on a 54 chevy 6cy! Car had sat for many years! Drive it 7-8 miles and it would die! I’d wait 10 min and it would start and then i might make it home or no! Dropped tank and cleaned it! Problem solved! This was after i had changed points, cond, wires, and plugs! Old timer told me what the problem was!

 

[Don Jacks]

Yes Barry,they did.You could be on to something there.

 

[Lt.FrankDrebin]

I'm going to start it up again today and when it starts to die, I'm going to remove the gas cap to see if there is a revival. I really don't think it's the ignition system because I am still getting a strong spark after engine dies and I did use new AC Delco parts. And when it starts to die, I first notice it when I go to rev the engine, although it's still idling fine at this point.

 

[1958 delivery]

I'm going to start it up again today and when it starts to die, I'm going to remove the gas cap to see if there is a revival. I really don't think it's the ignition system because I am still getting a strong spark after engine dies and I did use new AC Delco parts. And when it starts to die, I first notice it when I go to rev the engine, although it's still idling fine at this point.

also check if there is still fuel in the carb, if not it could be fuel pump

 

[32witha409]

Put a temp fuel pressure gauge on it. Not so easy if you have steel lines.

 

[blkblk63ss]

When it dies and don't start pour a little gas down carburetor and if it start again for a brief moment then you know it's gas problem. Does it have a sock on pickup tube in gas tank. ???

 

[NCPOP]

I had this happen before and it was a length of rubber fuel hose that was weak and pinching shut.

 

[Lt.FrankDrebin]

It's a fuel problem. I had it running again today, and like clockwork, it died after a half hour or so. I even pulled off the gas cap, but could not revive the engine. I disconnected a line going into one of the carbs and no fuel was present during cranking. I'm going to scream if this is another fuel pump issue. This will be the third one I went through in the 20 years I've owned this car and I don't even drive the car much. What could cause a fuel pump to quit pumping? I'm also going to look into kinked rubber hoses.

 

[blkblk63ss]

Sock in tank could be clogged, ,cracked hoses in lines sucking air or soft and collapsing and a defective gas cap then finally a defective fuel pump. Check filters after fuel pump. Check also for heat related to fuel lines too close to exhaust causing it to vapor lock. What are you using for gas ,might be eating pumps????

 

[Don Jacks]

Check all ,usually 3,section of rubber hose in the fuel line for cracks as well as kinks.

 

[blkblk63ss]

My son has a 64 impala and after setting a long period of time got ready to start .No fuel coming to carb so I replaced fuel pump ( stock) which I figured it should have been replaced any way for good insurance setting for years still no fuel. Checked all hoses and pulled sender to find the pickup tube completely varnished shut. Had to take choke cleaner and clothes hanger wire to dislodge varnish in tube.

 

[our1962]

Do what Don mentions above, I had a 66 chevelle doing the same thing. After doing everything you've done the problem was the 2 inch hose connection from the tank to steel line had a small crack causing the car to vapor lock.