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I have a 52 B3B that was overhauled and seems to run fine at idle and when increasing rpm in the shop.  When I drive it on the road it does not want to go over 30 mph and begins missing and sputtering some popping thru the carb.  the plugs are new, firing order is correct, plug wires new, distributor cap not cracked.  I have converted to 12V but did not change the points.  The points do have a frosting around them. I do not have a ballast resistor to the coil.  I am sure the valve timing is correct but have not checked it.  Any help would be appreciated.  Thanks Larry

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Hey! I am having the exact same problem, only my car isn't twelve volt. I thought the lack of power was the transmission, but now that I have it filled properly, I thing it must be a timing issue. Every one with a clue, jump on and help this cat get his B3b running, and hopefully I will find out something useful as well!

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Ledfootslim;

great name btw.....

 

You could try rechecking the point gap..set at .020"?...new condenser.....how is the rotor and the inside of the cap? any sign of arcing?

What is your timing set at? Have you pit a vacuum gauge on it? It should read between 18" and 21" at idle.

What shape is the carb in? How about the exhaust system? Any blockage would put you down on power.

Just a few things it could be.

 

Hth.

Jeff

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Did not mention- did you change to a 12 v. coil resistor type coil or std. 12 v. or no change at all??

Did you change the condensor in the dist.??

 

Points condition does not sound good at the moment.

 

DJ

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Well I solved part of my problem.  It had a 6-V coil. I switched it to a 12-V and it is working better but still has the surging problem.  I guess I created part of my problem.  I am going to rebuild the carb to see if that helps and will probably replace the points and condenser.  I will probably put in a .8 ohm ballast resistor. Live and learn.  Thanks for the help.  I will let you know how it progresses.  Larry

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Ledfootslim;

great name btw.....

 

You could try rechecking the point gap..set at .020"?...new condenser.....how is the rotor and the inside of the cap? any sign of arcing?

What is your timing set at? Have you pit a vacuum gauge on it? It should read between 18" and 21" at idle.

What shape is the carb in? How about the exhaust system? Any blockage would put you down on power.

Just a few things it could be.

 

Hth.

Jeff

Yes, I have reset the points multiple times, that is always what I think of, and the first thing my dad and grandad thought of. The rotor, condenser and cap are new, the carb was rebuilt with a kit from Andy BernBaum, the exhaust is all brand new, I split the manifold for a dual exhaust, and I have two RedHots for muffling. I'm not familiar with the sound of a vacuum gauge though, is it anything like a compression tester? Or does it have to do with the vacuum advance?

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If all of the components are confirmed good, the advance for the distributor could be the trouble.  The vacuum from the engine is used to add more timing through a small diaphram on the side of the distributor.  This allows starting with minimal timing, and the vacuum adds timing, once it is running.  There are also some centrifical advance pieces that shift the points and rotor once the engine makes some rpm.  With it running, watch the timing marks with a timing light.  As the engine comes up in rpm, the timing marks should move to show more advance.  This will confirm whether the timing advance is actually working.   

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Ledfootslim;

Look up reading a vacuum gauge online. There are some very good tutorials. It should become very apparent how useful one of these gauges will be to you. In my opinion they belong in every mechanics kit. It can tell you more about your engine than just about any other single tool you have. If everything is set up and working correctly you should see a very steady reading of about 18" to 21" at idle. A vacuum gauge can tell you all sorts of info on the actual running condition of your engine. Sticking valves......vacuum leaks... etc....etc. I like them so much I have one permanently fitted with the gauge mounted on my steering column so I can tell if all is well at a glance.

 

You may want to take another look at your carburetor. Did you fit the correct slotted gasket at the base to allow vacuum from the manifold to operate the step-up circuit in the carb ? There is a small hole in the base of the carb that feeds up into the step-up chamber. This needs to be clear and should be tested. Is the step-up piston and rod working smoothly. These can hang up due to wear or corrosion in the carburetor body. Either of these faults would have a negative impact on performance.

 

Jeff

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  1. I put the 6-V coil on and it helped.  I rebuilt the carb Stromberg BXVD-3 and that helped with the idle and lower speeds.  It is much smoother.  I can know get to 40 mph without the bucking.  But it starts again about 40.  I haven't replaced the points or condenser yet but will try that later.  I beginning to think it may be the vacuum advance. I appreciate the help.  Know is smarter than all of us.  thanks Larry

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I had a similar issue once. Engine would idle perfectly but when driving it would loose power, buck, and cough at around 35-40. I had just performed a tune up so I went back and retraced my work. It turns out I failed to properly attach the spring that came with the points. I found that at higher RPM the points couldn't close properly and spark would be very weak or nonexistent. I redid the points withe the spring attached properly, reset the dwell and timing and it's been running great ever since.

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  1. I put the 6-V coil on and it helped.  I rebuilt the carb Stromberg BXVD-3 and that helped with the idle and lower speeds.  It is much smoother.  I can know get to 40 mph without the bucking.  But it starts again about 40.  I haven't replaced the points or condenser yet but will try that later.  I beginning to think it may be the vacuum advance. I appreciate the help.  Know is smarter than all of us.  thanks Larry

 

When I got my D24 the vacuum advance was shot. It did not cause any missing and sputtering, popping thru the carb. Clueless as I am, I did not even know it was bad for a while.  Yours may be bad, but from what I have read it does not seem that it is the source of your problem.

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I rebuilt my Stromberg BXVD-3 carb.  This helped with idle and low speed performance.  I put in a 12-V coil a .8 ohm ballast resistor, new points and condenser.  This seemed to help but it still bucks' and once in a while pops thru the carb at 40 mph. When I accelerate at this speed it smooth's out to some extend.  When I suck on the vacuum advance it moves the plate in the distributor but will not hold the plate in the advance position.  So it is probably the diaphragm in the vacuum advance.  I am probably looking for ways to not spend money on it.  The vacuum advance is about $70.00.  Let me know if any one has had the same problem.  Thanks Larry

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lalkie;

Have you taken a vacuum reading with the engine running? Honestly this is a very good and inexpensive diagnostic tool.

If the diaphragm is leaking and you don't want to replace it at the moment you could try blocking it off. It won't run perfectly but it will run better if you eliminate the vacuum leak. You may have a vacuum leak some where else as well. A bad vacuum leak will make your engine run very badly even if all else is well.

 

Hth.

Jeff

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Can you borrow 2 tools from friends?

 

a pump type vacuum bleeder, because they have a vacuum gauge that can also be used to check an engine vac. as Jeff suggested.

 

a dwell meter to check your point gap, just not at idle but also a higher rpms to see to if it changes. If does much at all will show up any worn dist. shaft bushings. That check can also be done with just set your points on high point of a lobe and manually pushing the top of the shaft toward the high point and then away from it. should have almost no movement of the point gap.

 

I have seen so much wear in the bushings that a car that idled perfectly well after normal tuneup attempted almost be undriveable at any higher speed due to dwell change.

 

Another thought!

 

DJ

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If you do not have access to a vacuum gauge you could just block off the line from the base of the carburetor to the distributor and see how it runs like that. Also if you have vacuum type windshield wipers then that could be leaking too. Again just block it off and see how it runs. That connection should be on top of the intake manifold. Leaks like this can cause all sorts of problems with the way your truck will run......including popping and backfiring.

 

Jeff

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Too low.

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