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I have a 57 3100 with the original 235 in it. I have added HEI, alternator, Fentons, Offy 2x intake, Carter Weber dual carbs, new double pump fuel pump and more. I didn't change anything inside the engine.

I had been having an issue with charging but I think I have that resolved now. Late last fall I had some issues with the engine (used over 2 quarts of oil in 120 miles) but the compression seemed ok. She's started smoking and a lot of fuel is going out the back.

Yesterday I had a strange thing happen. I made a 5 mile trip to my favorite AutoZone to have the charging system tested. She ran ok. About half way home it acted like it ran out of gas. It just seemed to lose power and then stopped. I sat for several minutes and tried to start the truck and it started and ran about a quarter mile before it did the same thing again.

I assumed I was out of gas so I called my wife to bring gas. When I put it in the truck, it started and I drove it home. I assumed that was the problem. Later in the day, I decided to take the truck out on a short trip. About 2 miles out, the same thing happened again. I waited awhile and it started again and went another half mile or so before it happened again. This repeated itself a few more times until I finally got it home.

There's fuel in the glass bowl. What do you think the issue may be? The temperature was in the mid 80's with moderate humidity.

Thanks for any ideas you may offer.

Jerry

Is it flooding or starving when it quits?

Gas cap not venting?

It's probably vapor lock. If it is, a new fuel pump is in order. The next time it happens take the top off of the air filter & work the throttle. If you see a solid stream of gas squirting out of the accelerator pump it's probably not vapor lock but if you get mostly vapor instead of a solid consistant stream it probably is. You'll need a flashlight to see what you need to see. Good luck.

You seeing much sediment in the bowl? I had a clogged inline filter once that had these characteristics.
I'm wondering also if you got a loose weave rag/cloth, something that breathes, take your truck out and try to repeat discrepancy, then put rag (or nothing if you're comfortable with that) in place of gas cap. Would be an easy check.
Keep us updated, I'm curious.

Do you have a heat insulator between the intake manifold and the carbs? If not, you may be experiencing percolation. Heat transfers from the manifold (I'm assuming that since it's an Offy, it's an aluminum piece) and into the carburetors. I don't know much about the Carter Weber carbs, but if they're like Carter/Edelbrock AFB carbs, they're aluminum, too.

Aluminum is one of the best conductors of heat around. When the motor and underhood temps rise, that heat is transferred to the intake manifold. If there's no thermal barrier (wood, composite or phenolic spacer) between the manifold and the base of the carburetor, the heat is transferred to the body of the carburetor where it transforms the float bowl into a percolator. The heat causes the gasoline to boil away...and once it starts it only gets worse as long as heat is still present.

When you shut the motor down, (or it does it for you) the heat can decrease to the point where the float bowls are below the boiling point of gas...and the incoming gas from the fuel pump will cool it even more...until the cycle starts all over again.

I've seen this happen over and over again on smallblock V8s (big blocks aren't immune, tho) where someone has put on an Edelbrock aluminum manifold and an AFB carb that they bought at the FLAPS and as soon as the weather gets hot, they start experiencing problems. By the time they're replaced the carb, the coil, the distributor and a bunch of other stuff, they might take the advice given them and put a heat insulator in and, "voila!" the problem goes away.

I can't say with 100 percent certainty that it's your problem, but I'd say there's a pretty good chance of it.

Jerry, my 52 use to drive me crazy with silly dieing, would do it any time,, even on the hiway at hi-way speed,, never missed a lick, just would die when ever it wanted,,,,,,i put up with it for a while because it would always re-start,, even on the hi way , I could restart it by turning the key off and then on while moving.......my problem and I am saying this is yours but I have an mallary electronic dist, no points,, the problem was in the electronic module.. I replaced it about a yr ago and it has never stopped again,,,,,,,,,,it has a 58/235 , 12 volt conversion, etc..Fred

You said the engine at one point was using 2 quarts in 120 miles. Did it correct it self or is it still using that much oil? You said it was smoking and a lot of fuel was going out the back. What color was the smoke? (white, blue, or black). white is steam, blue (blue/gray) is oil, and black is fuel.
With the engine running can you see the draft tube on the rt. front side of the engine and is it smoking profusley? (bellowing smoke?) There should be a little even if the engine is running well.
The stalling condition you discribed is most likely lack of 1 of 2 things. Fuel or Electricity.
Do you have an inline filter? If so go to the filter with a glass container in hand remove the hose from the fuel tank side first and catch the fuel that flows out the filter in the glass. (note; fuel may also come out of the hose from the tank you can pinch off the hose to stop it or shove a large phillips head screwdriver inside it. Some old bolts have a cut off valve where the line gos into the tank.) Do you see any water or trash in the glass? If so you have fuel contamination in the tank. The filter is stoping up and engine quits running (starving for fuel) then you pull over let it sit and the dirt and crud fall off the filter surface inside the filter. It restarts and you drive a little further, it re-stops up only quicker this time cause the trash is still in the filter (just on the bottom). You will see fuel in the glass bowl if the in line filter is before the bowl.
It could also be a lose of electrical power, maybe from a bad connection or lack of and engine ground. You said you had some charging system issues. Did you fix them? A bad electrical connection or ground will heat up as you drive the make a worse connection and starve the engine of electricity this will inturn cause the vehicle to stall (just like it is running out of fuel). And when it cools off the connection is better and off you go till it gets hot again.
Thest are the things I would check first. Then I would move on to vapor lock, fuel percolation, or possibly stoped needle and seat in the carb.
Good luck.

Wow! This is a lot of feedback. I sure do appreciate it.

Grigg: I thought it seemed like it was starving but now I'm not so sure. When she's ready to stall, I can pump like heck and keep it barely running but then it dies. I's stick with starving.

Pakrat48: I wondered that myself. I've used the cap for over a year without any issues. I did remove it and try to run without to see if that would help. No change.

Tiny: I can't try anything right now. I've decided to go ahead with my engine swap and sort this out on the assembly side. I'll keep your note though.

Mugsy: I have 2 filters. I have a metal one near the tank that's new. I have a glass sediment bowl near the carb. It seemed to have some junk in it so I cleaned it out and blew through the paper. It flowed ok. I tried to run the truck without the gas cap and there was no change.

ChevyAsylum: I do have the plastic blocks between the carbs and intake.

Joker: The truck will not start immediately after it stalls. It takes 10-15 minutes before it can be started.

Toyvo: The engine still uses a lot of oil. The tailpipes are coated with some sort of black yuk. The blow by is blowing a lot of smoke. I believe the smoke is black. It doesn't look like there's any water in the fuel. The sediment bowl seemed to be all fuel. I do wonder about the fuel tank though. I've never cleaned it out. I may try flushing it out.

The charging issues were from a bad cell in a new battery that wore me out all last year. I had replaced the wiring harness and converted to 3-wire alternator last year so I chased everything except my new battery. This year I checked that battery and found the bad cell. I had the charging system tested and it seems to be operating fine. I killed the truck a few times last year running it until the battery ran down far enough that the HEI distributor would quit. Think I hurt anything in there?

Thanks again guys. Any feedback based on the above info?

It sounds like it's running too rich, then. Especially if you have the heat insulators and you're getting black smoke. If you were having blow-by issues, the smoke should be blue. Black indicates too much fuel.

What kind of choke mechanism to the Holley Webers have? Are they electric?

I really think the smoke out the back is attributed mostly to oil. I can't get a straight answer from the person that was following me the other day. I know the truck is running rich but I think we're seeing the oil more. The carbs have an electric choke. I have had trouble with those chokes. I have one blocked open. I didn't check the other to see if it was opening. I've never had them setup right. Those darn Carter/Webers are wearing me out. I'll have to get some help with them when I put the truck back together.

Well, Jerry, this is just a guess, but if the C/W electric chokes work like Q-jets and Edelbrock/Carter AFBs, then they have to have power to them in order to get them to open. If there's no electrical connection, or a full 12 volts isn't supplied (for a 12v model, of course) they won't open up and you'll end up with a very rich running motor. Having the dual carbs kinda complicates ths situation, but you may have one carb running with the choke on all the time and one with no choke. It'd still run rich under these circumstances.

When ya get it back together, I'd just observer the behavior of the choke blade on the carb that isn't disabled. See if it opens after power has been applied (or it's been running) for a while. If it does, then the problem is somewhere else, but if it never opens, you've probably found the culprit.

I'm kinda being a little evasive about when power is applied, because some setups have a switch that opens up when there's no oil pressure...so you can't test this kind of circuit with electrical poer on and the motor not running. I doubt you'd have this setup, but ya never know. A quick test with a meter would tell you what's being applied when.

Good luck with it.

In newer vehicles with all the electronics under the hood, the symptoms you described of dieing thn starting up again 15 minutes later would point directly at a faulty electronic component. It's not unusual for electronic components to fail when hot, yet operate fine when cool. The heat causes things to expand and loose contacts to open. In your case, the most likely culprit would be the HEI conversion. Short of replacing it and seeing if that fixes the problem, I have no idea of how to check it.

I am completely nfamiliar with the Carter/Webber carbs you have installed; so, I won't go there as regards your running rich/burning oil? problem. Since you say the compression is okay, have you checked for oil in the coolant, coolant in the oil? The oil loss may not be related to the smoking. It is kinda' hard to distinguish between black and blue smoke. Have you replaced the spark plugs recently? What did they look like, how do they look now? This could help in determining if you are just running rich or burning oil as well. Of course if you are running rich, ignition problems could also be the source or at least contributing factor to the problem.