The Stovebolt Site Forums The Shop Area Engine Shop Why I won’t journey far from home!

you might start it at night and see if you have any wires leaking or fire jumping......

look for the easy stuff first........I still think it is electrical

you might consider driving it to a mechanic.. see if he can tell you what is wrong with it...........then you can fix it yourself

Jerry's taking a break...

Denny:You know that the vacuum only works at low RPM's let's say up to 1200 after that the centrifugal advance comes in and takes over at this point you can throw the vacuum advance away. do you have a timing light with the dial on it I'm going to guess that there should be about 24 degrees total advance set the dial to 24 degrees run the engine up to about 1800 and see if the ball lines up with the mark and if it doesn't turn the dial until it does then you will know it not in the dist.You have no vacuum to the dist. at idle because the vacuum port is above the thottle plate as soon as you open the thottle air moving across the port hole starts a vacuum pulling the advance open. And your saying that the only way you can came the engine run is at full thottle if you had a vacuum gauge on a normal running at full thottle the gauge would show zero and as far as the backer fire if the engine leans out weather because the jet pluged or not enough fuel is getting to the carb the cylinder tempature is going to go up high enough to get a piece of carbon glowing and firing the charge when the intake valve opens also even with a fuel pressure gauge you may have pressure but no volume Just a thought.

Paul

I had similar symptoms that traced to a broken wire going to the coil. The outside of the wire looked fine, but it was broken inside the insulation. Wiggle it right and it would lose power, then it would come back. Took forever to find the problem. I replaced everything but the wire. The my Dad came by, had me fire it up, and started shaking everything under the hood until it acted up. Evidently he had seen it before as well.

Denny: does your truck still hve the cross shaped shut off valve on the bottom of the tank could it be pluged with crap from the tank. Just a thought.

Paul

Hey guys enough with the clogged fuel thing, I'm getting fuel, I can run at 60mph as long as the throttle is wide open, clogged fuel lines won't let you do that! There are two filters, before the carb, the screen in the fuel pump and the AC inline glass bowl paper filter, both run clean, it's not starving for fuel!

And Paul, I wasn’t going to bring this up before cuz I didn’t want to start an argument and veer to far off course, but from my experience as a pilot I would have to disagree with your understanding of carburetor icing. Not that I was having a problem with carburetor icing in this case, it was just a thought that raced across the old brain. But a quick search yields a quote from Lycoming which explains it much better than I could and should make it a little more clear to you, why that thought crossed my mind:

“Your carburetor can get pretty cold. The heat loss from evaporation of gasoline at the stoichiometric ratio creates a theoretical temperature drop of 40 degrees F. The adiabatic expansion of gas across the carburetor's venturi also lowers the temperature. Thus, you could drop the carburetor temperature to freezing and form carburetor ice at an ambient temperature of 72 degrees or higher. Stoichiometric is the leanest possible mixture.
At richer mixtures the ambient temperature at which carburetor ice forms is even higher - Lycoming publishes a temperature range of twenty to 90 degrees F. for carburetor ice.
Adding alcohol to gasoline dramatically increases the ambient temperature where ice forms. Evaporating methyl alcohol creates a temperature drop of 300 degrees F. As a result, carburetor ice occurs over a wide range of temperatures.”

And since I don’t have the bench testing equipment at my disposal, I’m going to be at rest for the next few days till I get a new vacuum advance, coil and condenser and can change a few parts out. And not that I'm ignoring your contribution Red Ryder, but, lots of buts here, from my years as a Chevy Parts man in several Chevy dealerships, that’s about the way your mechanic would approach the problem, even today. Passed out lots of parts that ended up back on the shelf before the job went out the door. Just like a medical diagnosis, not every problem is clear cut.

Denny Graham
Sandwich, IL

Back when I had a 2-pack-a-day Winston habit, I tested vacuum advance units by trying to blow smoke through them. It sounds like the vacuum numbers from the carb are about right, as the maximum vacuum will happen at a steady-throttle cruise. it will just about disappear at wide open throttle, as the spark needs to retard during acceleration.

I don't think a bad vacuum advance will do much more than give lousy gas mileage, as most of the advance is done by the centrifugal system and the vacuum just kicks in for better fuel economy at cruise speed with a light load.

The need to choke and/or pump the throttle to keep running sort of leads me to believe you're either dealing with a primary wire inside the distributor that is intermittently going open-circuit due to vacuum advance movement, or you're starving for fuel. Try this: Disconnect and plug the vacuum advance line so the dizzy doesn't move, and see if the problem goes away. If it does, change the primary wire from the distributor housing connector to the points.
Jerry

OK....my two cents...dad had the same problem with a Chevy truck V-6....the PO has lost the gas cap and a rag had fallen in the tank and caused the same condition...man they changed everything! But in the end it was the rag in the gas tank. Even the old mechanic what worked on the truck installed an electric fuel pump to get around the problem. Not your problem I'm sure but just to point out how frustrating it can be. Once you get her fixed it will be a good thing for all of us to find out what had happen! Keep the faith!

PS... from my 81 yr old uncle...nothing wrong with the Rochester B millions of them made and still running. Most of the trouble is with the owners that fuss with them and they don't have a clue! Get rid of the heavy oil bath air cleaner if its on the Rochester. UNK

Jerry, you can see from this picture that the wire from the coil to the distributor was new when I rebuilt the distributor. http://rides.webshots.com/photo/2006464220098611668iIwnEb
And this is the inside of the distributor as it is now. http://rides.webshots.com/photo/2322951040098611668lTygHE
The only wire inside the distributor is the condenser wire.
Waiting on parts this week end.
Denny Graham
Sandwich, IL

I have been reading through what all you have done. The problem from the beginning sounds like a bad coil to me. Back when your vehicle was young, it was quite common In fact a spare coil was one of the spare things we carried under the seat our GMC's back during the 50's. When coils get hot, they expand. If the insulation is bad, the windings can ground against the inside of the can. The problem isn't very common today because I suppose the insulation is better. If you have a coil around that is known to be good, try it. If you don't have a coil around, I would suggest buying a new one. I think it's worth a try with all the trouble you have had.

That's on of the parts I have on order but won't have anything till next week. So I'm just takin it easy this weekend.
I popped the distributor back in as Jerry suggested and plugged the vacuum off at the carb. Gonna try to take her out for a ride after supper and she how she acts. If nothing else I will know for sure how this engine will act with a bad advance.
Denny G

It shouldn't be a bad vacuum advance, my '54 runs just fine without one, except occasionally when ya hit a bump and your foot hits the pedal too hard, then it stumbles a bit, but let off of the pedal again and all is fine. My yard is big enough to get the engine speed up(in first) without being in danger and the only thing the vacuum advance does to my 235 with a Carter Y-F(Yes I know two different engines, and carburetors too) is make the two gallons in the gas can disappear faster. But at least you are buying something that needs replaced. Here's something I thought of, not sure how safe it is, but drive around until it does the backfiring, then take it home, pop one of the sparkplug wires off and see if they arc when you have someone turn the engine over. Don't know how but you may be able to do so in a safer way? If not then don't try it if it isn't safe, don't need anyone getting hurt.

Hook you'r timing light to it and run it in the cab, drive it,When it act's up Watch the light,if it's ignition, you'll see it..

Thats kind of what we did in the 50's. If the popping in the am radio quit while we were coasting to a stop, it meant dead ignition. If it kept popping, it was fuel.

Someone who suggested a loose connection at the distributor may be right, since the distributor body rotates when the vacuum advance moves but not when the mechanical advance works. Another place to look is the little bolt through a block where the points connection passes through the distributor body. If it cracks it can short out. I would try wiggling wires while the engine is running and see if you can get it to skip. Some of those symptoms may not show up unless the engine is under load, though.

Alternately, check the ground strap between the engine and the frame. You could have a faulty ground that shifts around as you put torque on the driveline, and you complete the circuit when you floor the gas pedal and the accelerator rod hits the body or something strange like that.

Chalk another one off J. all the electrical connections are as solid as a rock. I removed everything and replaced it all just a couple thousand miles ago. New cables, cleaned frame connections on frame down to bare metal, new wires from coil to distributor, complete tear down and rebuild of 1112353 distributor. That's all just fine, I've had the distributor out and checked all of the connections with a meter for continuity and any intermitance, just fine. There are no loose or broken wires.
Waiting on parts now.
Denny Graham.

Well we certainly have had about every guess that there is on this one. and I've checked out about 85% of those that made sense. And I'm hoping to eliminate a couple more of them today or tomorrow when the new parts get here.
The one thing that is still on the list is the fuel itself. Being a creature of habit, I always buy my fuel from the same place, the same pump and the same grade. If I could get the 15gallons of fuel emptied out the next fill up I'll try a different station, like a big name brand, BP or something.
Denny Graham
Sandwich, IL

I know you've just about ruled it out but speaking of gas tanks and fuel, the smart money these days is on replacing all rubber fuel lines with this new stuff that's supposed to work better with ethanol blend. I've heard of some fuel lines cracking after only a few months.

I know when it comes time for mine, I'm going that way.

Hate to leave an answer hanging Josh but I didn't have time to post these pics of the electrical connections. I know a lot of guy will tell ya that they checked it all when in reality all they did was knock the dirt off. So for what it's worth here are a few pics of just what has been done to mine in that area. And one of just how far I took the distributor when I rebuilt it. http://rides.webshots.com/photo/2812805100098611668RyYMtY
http://rides.webshots.com/photo/2804284430098611668MLTnoC

Woody, I haven't pulled the flexible fuel line off the tank, like I said I have a full 15 gallons in there right now. But, the line has a date tag on it and it looks like it was replaced in 2006 probably right before I bought the truck. That's the only rubber line on the truck for fuel, just an 8" long piece.

I advanced the timing about 10° this morning and took it out for a run around the town square. It was smooth a silk till it warmed up and as it approached the 180° mark I could feel that flat spot coming in when I start to accelerate. I didn't run it far enough to really get it warmed up, like a 10mile run, for fear that she would start that back firing and real severe hesitation again. But I did nurse it up to 55 and I say again, it isn’t running out of fuel while running along at a steady speed.

Just can't make any sense out of this. This was a truck that a month or so ago I had running so nice that I felt confident enough to drive just about any where. I was taking regular 100 mile round trips with it a couple times a week. other than the Rochester acting up once in a while everything else was fine.
Gonna put a new condenser in this afternoon and the new coil is due in Tuesday, those are the next things to chalk off the list.
Denny Graham
Sandwich, IL

Denny Graham,

I haven't followed the novel so this might be old news. What is the wire leading from the common post on the distributor...your handy dandy homemade tach! Could this be part of the problem?

Stuart

After all this, I would bet a bottle of beer that the coil is the culprit.

Yep, green wire is tach signal, and yes it was acting up before I hooked the tack up. But I'll pull that wire just so I can chalk your suggestion off the list.
And we will know tomorrow if the coil is the bad guy.

I gotta throw this in here. I changed the condenser a couple of hours ago, no other changes, and took it out for a jaunt up town, bout a mile or so. She was behaving real nice before she warmed up. Once she came up to temperature I was feeling a little hesitation but decided to keep driving her till her manners got real bad. Actually drove it for about an hour at speeds up to about 60 and although there is still a little hesitation on acceleration I didn't encounter any backfiring or any of the real bad flat spots I had before. When I got back to the garage I checked to see how the timing looked and she’s right about where I advanced her to this morning, about 8 or10 deg.
I also have a new fuel flex line coming with the coil tomorrow. I'm gonna try to run out this tank of fuel this week and I'd like replace The line and pull the valve off the tank just so I can check a couple more items off. The shutoff looks like it can be disassembled and then the only thing left in the fuel system that is untouched would be what ever is in the bottom of the tank itself. It looks like a pipe nipple coming out of the bottom of the tank. I thought someone had said there was a screen in the bottom of the tank, don't look like it to me.

On the timing mark, anyone know what the UIC stands for? http://rides.webshots.com/photo/2541872790098611668jxhMba

Denny Graham
Sandwich, IL

Chalk off the green signal wire for the tach Stu, makes no difference.
Hey Crenwelge, is that just a guess or do you have a logical reason for thinking that the coil is bad??? This was suggested a few days ago and I, for the life of me, can't see how these symptoms could point to a bad coil, or condenser for that matter.
Denny Graham
Sandwich, IL

A coil will fire fine until the engine is warmed and the heat causes the coil to expand internally and quit firing. However, I have not seen a bad coil that would continue to fire after warming up. The ones I have been around would cause the engine to die(or quit firing). Of course after you sit on the side of the road long enough for the coil to cool off, the engine would fire up and run great until the coil heated up again and the engine would die. If you rev the engine a little while parked until it warms up, does it start to lose power or is it only under a load? The backfiring through the carb indicates a change in timing. At first I thought it was the dist cap, but now I am leaning towards a bad coil wire or coil although it would be the first bad coil I have heard of that would hold current while warmed up. Joe

When coils get hot, they expand like anything else. If there is insulation bad in the coil, the windings will expand to where they ground to the can or the metal part of the coil. It usually starts with an occasional miss when it is hot to where it finally gets real bad. Condensers are usually dead or alive and when dead stay dead. Coils come back to life when they cool off. It was common enough that my father kept spare coils under the seat of our trucks that we delivered fuel out in the country with. My first guess would have been vapor locking because it's the most common. My next guess is the coil because they also fail when they get hot. Be interesting to see what develops tomorrow. However if it still does it with a new coil, you mention the shutoff valve under the tank. There is a plug on the bottom of the petcock. Remove it and see if any trash comes out. This is the spot where trash likes to settle. Be very careful when you remove the plug. Hold the petcock with a vice grip or something. There is a brass 1/8 pipe nipple about 2 inches long that goes into the tank and it is very easily broken. With the plug out, root around in there a little. Oh, by the way. something else that can happen is the wrong gas cap. These vehicles were designed for a vented gas cap. I remember putting an unvented gas cap on a school teacher's pickup. He drove most of the way home and had to walk the rest of the way. We followed him and when he was out of sight of his pickup, we put the correct cap on and I suppose he never did figure out why his pickup quit.

Well Joe I would agree with ya all the way down the line, and that’s the thing that is baffling me. Timing doesn’t change and change back exactly where it was before the problem started. And a bad coil is a bad coil, once the insulation breaks down and shorts it isn’t going to heal itself.
Now let me take some target practice here, I’ll see if I can shoot down some theories.
Coil gets hot, coil shorts out, coil is dead, truck doesn’t run. Not the symptom, this truck runs just acts retarded when you feed it throttle.
Capacitors are subject to aging since the foil is made of aluminum it as they absorb moisture and the foil breaks down or oxidizes over time so they will change value. If they are hit with a higher voltage than the dielectric designed for then it can open. Can’t see how this would affect the throttle response that I am experiencing.
Vapor lock has not been experienced by any of the Advanced Design owners that I heard from, most of them that answered were running trucks in the south west where temperatures are well over 100 on the highways.
Gas cap not vented. This is the gas cap that has been on the truck for the last four years that I know of for sure. Never been a problem before, and I checked the vent and it passes in both directions. Besides it is not starving for fuel if I can run at 55 or 60mph.
So that puts us back to square one again.
New parts tomorrow!
Denny Graham
Sandwich, IL

Denny Graham,

In regards to the coil deal, I understand it a little differently. The primary windings don't short out per se, they short out turn to turn thus reducing the affected primary number of turns..this makes a weakling out of the coil.

As the under hood temps increase, so does the coil and the resistance in the wire. The already marginal coil now has to fight the increased electrical resistance and falls into the marginal catergory. This results in weak spark and loss of power. This is how I understand it, but I'm just a recently retired Millwright on a fixed income.

Stuart

I have never been inside a coil to see what was shorting when they got hot. The old timers seemed to think it was shorting against the can. Maybe they short between the winds which actually sounds reasonable. But the bottom line is they throw a weaker spark when they get hot, and I have seen quite a few of them function quite normally when they cooled off. I have also seen them get so bad that the vehicle stopped. The vehicle was allowed to sit over night and the next morning it started as usual. By elimination, I still think the coil is the prime suspect.

Well it's 05:30, the first cup of coffee is half gone and the dog and I are sitting on the porch waiting for the UPS guy to show up with our parts. We will see some time today but I'm only giving it about a 50% probability.
Hey I want to thank all you guys for your help, I know as Stu eluded to, this has turned into a "novel" but this thing is really a bit*h of a problem.
Another hobby of mine is antique tube radios. Intermittent bugs are the biggest pain in the ars to find in them just as they are in an autocar. Replacing parts as a last resort as a process of elimination and is about the worst way to find a problem but sometimes it's the only way.
I don't have access to much automotive testing equipment other than a timing light and vacuum gauge and that makes it a bit more difficult to pin down this sort of a problem. My brother has a complete Sun Testing setup that he got from a “real Service Station” that was shutting down to make room for a Quick Mart. I mean this was a permanent built in setup that covered the back wall in the shop. You can nail down a problem with the distributor machine in no time. But we haven’t talked in years and he’s living in AK now days anyway.
Sun’s coming up, I need a fresh cup O’ Joe and I better get breakfast started for my, “big old wife”.
To be continued.
Denny Graham
Sandwich, IL

While we're all sitting here waiting for the UPS guy, here's a little story about waiting for parts.

I had a friend lined up to help me hang my driver side door Sunday if the hinges got here in time. Well, I went to the post office on Saturday and no luck, so another week down the drain waiting for parts.

So Monday I'm coming home from my morning walk and notice my mailbox is closed. Because this town is so small, until just recently we all had to go to the post office to pick up our mail. Guess what... as of late last week we now get mail delivered to our house... the hinges were sitting in the mailbox all along and I didn't even know it.

Now the birds are going to have to find a new place to build their nests, but at least I'll get my mail delivered to the house.

Isn't THAT exciting?! Zzzzzzzzzzzzzzzzzzz

Now I need more coffee.

I haven't heard of any one who plays with tube and chassis radios in a long time. Back in the 50's I used to assemble Heath kits and Knight kits. I lost interest when printed circuits came out. That was my rainy day hobby when it was too wet under my shade tree. I still do most of my work on my jalopies under a shade tree because we have to maintain our trucks in our shop and I only go out there for special problems. Be interesting to find out how the cliff hanger ends. I have known coils to break down with heat, and I can never remember a condenser in a distributor being intermittent, but there can always be a first. My bet is still on the coil.

You lose! New coil installed this afternoon and I took her out for a ten-mile run and I still have the hesitation or flat spot when I accelerate. It hasn’t done its little backfiring thing the last few times out, but still has that darn flat spot when you push down on the accelerator.
Still got the vacuum advance to replace, the fuel flex line and check out the fuel shutoff petcock. After that every thing in the fuel system and ignition will have been replaced.

I made some measurements with both of the coils on the bench and thought I’d found the bad guy. The old coil was a Delco 1115380, which is an original Chevy part number, very well might be the original coil. The primary measured 1.2 ohms and the secondary measured 5.24k ohms. The replacement I got today was from Classic Parts (Chevy Duty) and its primary also measured 1.2 ohms but the secondary was 8.86k. Not having a new Delco or even another used one to compare it to I didn’t know if it might be shorted and should read higher or if this was normal a normal resistance for the secondary. It is the only one they had listed in the catalog but I noticed in Chevs of the 40’s that this coil is listed as a 6v/12v replacement, which would account for the higher resistance of the secondary. They also have a 6v coil listed from Pertronix that I think would be better matched to the 6v trucks.
As far as this replacement coil goes I have a whole lot to say about that but I’ll vent that in another thread another time.
But after all is said and done, it twernt the coil.
Denny Graham
Sandwich, IL

Denny, you are fighting two different problems. The coil and or condenser fixed the back firing problem, as of two drives that is gone. The hesitation off idle is a carb problem.

The two are not related. Even vacuum advance won't cure a off idle bog. Vacuum will drop off when opening the throttle so the advance is backing off by the time you are rolling. The mechanical hasn't moved yet ether due to rpm. Don't bother with the fuel tank or lines, they sound just fine and your ten mile drive proved that. If it runs at full throttle or even after it bogs a bit, your fuel system is working.

Check the accelerator linkage and pump. It should shoot fuel just as soon as you touch the throttle. If not bend the linkage or adjust what ever is there so it squirts fuel as soon as it can. You may have to play around with it a bit.

Joe

That's not the first time I've been wrong, but my diagnosis was for a sudden backfire through the carb after it heated up. I don't think you are going to fix the problem by changing the fuel line, but I would do it because that might be your next problem. Same way with the fuel shut off. Trash likes to settle there and you could very well have trash beginning to settle there waiting to cause your next problem. But be careful. The 2" nipple going into the fuel tank is easily broken and then you usually have to take the tank out to get the broken piece out. If a flat spot is all you are dealing with now, I would look at 2 things. Either your your carb has the float level set too low or the accelerator pump isn't working. Just because you have been in the carb doesn't doesn't mean you don't still have carb problems. Anyone who has rebuilt carbs has had times when they had to go into it several times before they got it right. The vacuum advance should have nothing to do with your problem. It advances when vacuum goes up. This is not the case during acceleration. However the centrifugal advance does advance the spark at higher rpm. A quick check to see if it is working at all is by removing the vacuum line to the vacuum advance to disable it. Put a timing light on it. Rev it up and see if it advances. If not, that will definitely cause a flat spot in acceleration. If it doesn't advance, take the breaker plate out and see if you have broken springs or things rusted together. I don't think you can get these parts at NAPA etc. Farmall/International tractors used the same advance and I usually get parts there.

Denny - I think Joe may have called it. The coil fixed the backfire. Now lets talk about the hesitation.

Does it hesitate EVERY time you accelerate?

If not, just off-idle, at 1000 RPM, 1500 RPM, 2000 RPM, etc.?

Do you still have the W-1 one the engine?

If so, did you check the wear areas between the throttle arm and pump? These are the round hole in the throttle bracket arm may become elongated (replace bracket)? The rod connecting the throttle arm bracket may be grooved (replace rod)? And the same two issues at the top end of the rod.

There should be miminal play from movement of the arm to movement of the pump.

But also check the distributer plates as posted by crenwedge.

Jon.

The vacuum advance comes in as soon as you ease in on the throttle Joe, it falls off around 1800 to 2000 rpm when the centrifugal advance takes over and is handling the chores.
The Rochester ‘B’ is off and Carter W-1 is on, there is the same exact hesitation and stumble as before when you add throttle with both of them. If ya have doubts as to the level that the carb rebuilding was taken to, take a look at the album. Both the Rochester and the Carter are well documented. The Carter carbs throttle control rod linkage is very precise in it’s setting as Jon can attest to. I was cautioned by him that even any wear in the linkage connections can cause problems as you come off idle, so those clearances and adjustments were held very close and checked with the T109-25 standard gauge and a dial indicator. Because of the simplicity of the Rochester there is no such adjustment for the accelerator pump.

I’ve said at least a dozen times in this “novel” that it’s not starving for fuel, even begged that that not be brought up again! But from the nipple coming out to the tank all the way to the carburetor insulator, it is, going to be all new just so I will not have problems on down the line.

As for the ignition, from the distributor, which again you can see the level of restoration documented in the album, all the way to the new plugs and from the battery thru all of the grounds and cables all is new. The original chassis wiring is all intact and in very good shape, under the hood and under the dash. It has never been messed with and all of the continuity checks out and there are now shorts to ground or between wires.

Of course logic would suggest that one would start looking at the accelerator pump or low speed circuits in the carb first with a stumble when throttle is added, that was eliminated 300 pages ago. Then one would look towards the timing. But add to that the backfiring whenever you added throttle and that would lead you back to an ignition timing or maybe a stuck valve. But this backfiring was to predictable to be a stuck valve so this was also eliminated. This truck has done this on a couple of other occasions, which prompted me to go through the Rochester again where nothing was found out of place. Then it cleared up for a while till this last bout and now that seems to be clearing up.

I know there is a ton of crap to read here, if it were someone else’s thread I would probably ignore it by the time it got to be this long but most of what your suggesting has been covered several times and I’m at the stage where I’m just going to Shotgun it which still doesn’t appear to have it nailed down yet.

Those of you that have gotten to know me over the last couple of years know that I won’t let it go till I nail it down and when I do I will document it so the next guy might get something out of it. Also I’m pretty, maybe not the most, but pretty meticulous about the work I do. I get a lot of enjoyment from the process and take a lot of pride in doing it. This is certainly not a “Text book case of diagnostics” and there are times when logic just doesn’t apply until you find the solution, then it can be explained in a logical manner.

Well guitar lesson today, vacuum advance this afternoon and burn more gas tomorrow till the tank is dry! Gotta run, can’t play anymore.
Denny Graham
Sandwich, IL

You previously mentioned that you had an extra distributor. If you haven't already switched it out, now may be the time (or when you get the new vacuum advance....no sense pulling it twice). I had a similar problem and the distributor fixed it. I used a timing light on each plug wire and some were firing intermittently, must have been a bit of slop in the bushing. Nothing to lose since you're changing the vacuum advance. Good luck!

I know this is very aggravating for you Denny but I also know that you will eventually get it figured out and corrected. Just stay patient and focused, often times getting upset clouds your ability to see even the clearest of things.

I don't think very many of the better mechanics are bailing out of this thread. They are probably scratching their heads as hard as you are. I know I'm dying to find out what it is.

Hang tough.

Denny, I don't have any answers for you, but for what it is worth you have my sympathy. Last year I changed a couple of things on my 52. For the next 3 months I couldn't get it to run. I was so frustrated I thought about selling the truck. For two weeks I didn't even look under the hood. I read hundreds of pages here on several componets. After the time off I redid a couple of things and now she runs. She still has a habit of coughing at 40 mph or so that I haven't corrected, but at least I can drive her. So hang in there you will figure it out.

For what its worth to all following this thread and it may sound really stupid but in my 1951 1 ton with 216 and rochester carb, I had same symptoms as described by Denny. Engine ran fine without problems until down the road 5-10 miles. Then it would start acting real funny, dieing, lack of power, backfire, ect. Thoughts of i am going to be stranded going thru my head. Pull full choke and limp on home. Check carb, plugs, points , timing,fuel filter and pump, hoses ect, no problems found, next trip, same story. Just by chance, and I can not swear that it solved the problem but I went from a 195 degree thermostat to a 180 and problem went away. I have followed this thread from page one and it seems everything else has been tried.Just for what its worth to any of you experiencing similar problems. Jerry from Minnesota