VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 hard 1940 problems

Hello everybody,

my beloved 1940 special deluxe decided to become a troublemaker, sad, but fact.

What happened?

One week ago I did open the season and the first trip was to gas station, about 5 mls and back to adjust the tire pressure.
Way from home to gas station, no problem, she did run perfect as all the time before.

Backwards home I made a short passage with full throttle, again no problem.
Last part of the way with something about 50 mph the trouble began. Stuttering, lack of power, had the feeling of a problem on gasoline side. And, what miracle, after about 15 seconds the unexpected engine stalling it was over and she did run perfect as before.
Had no idea what happened.

Next day I wanted to do a trip, but it began again. Engine stalling, stuttering, sometimes bangs from exhaust, no power, shut down. Impossible to drive. Could not leave the garage.
Ok, had two ideas for first try:

1: The gasoline filter (additional inline fuel filter) at the gasoline tank outlet is maybe blocked,
2.: Maybe the gasoline is bad, could happen with modern ethanol-fuel as we have here in germany.
work 1.: Did change the filter and check the other one glas bowl type at the fuel pump.
work 2.: Bought a canister fresh fuel from gas station and made an improved fuel line to feed the car from canister instead of car tank.
Did as well check how much the fuel pump can pump. Did disconnect the fuel line in front of the carburetor and made a small hose to fill the fuel into an old beer bottle instead of carburetor .

Fuel pump ok, pumps a lot. Half beer bottle filled within seconds.

Result of first try? Just nothing better than before. Stalling, no idle, banging, shut down.

To describe the next resultless steps short. Next try. Ignition side to be sure there is everything ok. Change and putting in new parts. Coil, all spark plugs, distributor rotor and cap, points, condenser. And I made an improved control light showing me inside the car that the coil gets energy. A friend had the idea there could be something wrong and the coil gets no energy.

Additional info: All electric wiring is new and works.

Timing setting is perfect as the work shop book says, intake-outlet valve clearance is as it should be. Made complete service before garaged winter sleep.

No better result. Stop: Just one difference. There was one moment she began to become quiet, smooth running, perfect idle, was happy and thought “got it” and let her run and warm up and prepared for a short test ride around the block about 1 mile. First perfect and good, but at half way the damned stalling, stuttering began again everything as before. Motor died middle in the street and I had a lot of honking cars behind me. Could start again and was able to crawl and limp back home sad and very disappointed.

So electrical is done, to continue at carburetor side:
Took it out and put it apart to clean everything, could not imagine that is the problem because about 400 mls before I did a carburetor (Carter W1) overhaul with the overhaul kit I bought at Filling Station, Oregon and had never a carb problem before.

Cleaning everything, reassembling made exactly no result at all as all steps before. I run out of ideas what it could be.

Now I did spend about 20 hours since monday and she does not run at all. It is possible to start, but there is no idle and than after at least 20 seconds the engine dies.
I have no idea anymore, where to find the reason for that problem. Today I made a short video of the stalling engine to show it to a friend in NC and he answered “I have no idea what happens, I am baffled”.

Does anybody here have an idea where to continue to get her running?

Otherwhise the number of running 1940 chevy cars in germany would be reduced to at least zero.

Regards Stefan

Initially it sounded like either some bad gas, some gunk stirred up in the tank which plugged the carb or possibly some corrosion on your points from sitting.

You've touched so much now it's confusing but the bad gas or dirt in tank scenario could still exist and be causing this. You could have added a new additional problem like a weak condenser. Your timing can be set a bit more advanced than the original specs and will actually run a bit better.

Can you run some fresh fuel from a can? If you pour some down the carb does it then run briefly? I would try some fresh fuel and then ONE change at a time starting with timing, condenser, points and see what happens...

.Bangs from the exhaust leads me to believe it is an ignition problem. There may be a poor conection or broken wire.

Sorry to hear about your problems. I know you work very hard to keep your car in top condition.

You might want to remove the top portion of the carburetor and look into the fuel bowl. Even with a fuel filter there could be dirt that is blocking the fuel flow to the main jet. You will also be able to get an indication of the fuel level in the bowl.

Another quick thought - check the air cleaner to make sure no little varmint decided to make a nest in it over the winter!!

Check the following:

Sounds like an ignition problem to me.

a. Spark plugs.

b. Wiring from distributor and distributor ground.

c. Choke connection and operation.

d. Ignition to coil connection.

e. Blow back fuel line from fuel pump to gas tank.

f. Drain gas tank. May be some water has collected or some rust or sludge. You may be able to determine if there is trouble there without a complete drain. Be extra careful when dealing with gasoline. Just saying.

g. Recheck timing, plug wires, and points gap.

If none of the above helps, put a 9MM round through the engine block.

Best of luck,

Charlie

I had an experience very similar to yours a couple of years ago, in my 38. It has a 1940 216. In the end it was caused by a bad condenser. The condenser was less than six months old. I had to have it transported home on a flatbed. I could get it to run and then it would die and backfire etc. I had changed the coil with no improvement. I have a timing light which has a neon light and is powered by the spark plug wire. I hooked it up and set it so that it was pointing at the windshield. When I tried to run it, I could see the spark fail as the engine was starting to die.

I now have a nice vintage Heathkit ignition scope and I am going to use it before any major trips. The problem would have shown up on the scope.

I had the same behavior a few years ago with my 1940 coupe. Ran well for a while but then sputtered, coughed, stopped. Took 2 hours to limp home.

After much trial and error doing the kind of stuff you reference, it finally did perform flawlessly on one of the long test drives. When I got home, I realized I had left the gas cap off.

Only thing I can figure is that the fuel pump was drawing a vacuum in the gas tank and eventually starving itself.

Got a new gas cap and no more problems.

Or maybe the gremlins just went away?

X2

Jon

OR CONDENSER

Today I renewed the last existing "old" wire (I replaced it last in 2011) from coil to breaker point, made new timing and breaker point setting and whow, she started and did run perfect.
I made a very short test ride, half mile away and back and the car did run good.

First I thought, Ok, problem fixed, but one second later I thought the old cable had nothing, no interrupt, just nothing. Why the car runs with the new cable and not with the 8 year old one??? Did not understand that but I understood I should not trust that nasty kind of scam success.

went later on a bigger test trip and just until warming up and reaching the first red dot at temp. gauge the disaster did start again. Same as before, and loud bangs as loud and brutal as possible. it did bang my not old and rust free like new muffler apart.
To crawl home with the not running, only stuttering and banging engine was pure horror. The motor was able to run, very bad, but I had the chance to check the ignition with my ignition test stroboskop light which is detecting the firing of 1st cylinder. And again, as yesterday I had no reliable signal for that cylinder.

Now, with a bit cooled down brain.

It must have to do with something getting worse when everything heats up.

Remembering:
1st time, last week it happened first ever, during first ride after winter when I returned from gas station where I went to bring the tires to correct pressure. At the gas station it was for about 15 min to wait for the air pump and to answer peoples questions about the car, and it was a sunless cold day, I drove with switched on heaters. Means, the car did not heat up to first red dot until I was driving back home.

At way home the stuttering began first time ever and after at least 10 seconds there was a kind of self repair and it was gone as it would never had happened.

Later it did happen when the motor was cold and I went on a test ride and during ride reaching the first red dot on temperature gauge the disaster began.
From last monday to today, one week I did search for a carburetor problem and had the carb. more than one time apart to check everything and found nothing suspicious.
Aside I did change as written in first message: Coil, distributor cap and rotor, breaker points and main cable from ignition lock to coil. After that she did run good but again there was not one changed part I could say clearely the old one was over for sure. Did run and I didnt know why.
On first test trip as short as possible the motor did not heat up until first red dot on gauge and nothing happened.

On next trip a bit more, the motor did reach first red dot on gauge and the disaster was same as before.
When I got her to a shaking, stuttering idle (hard to get) I tried to check ignition with my stroboskop flash light and did see there is no reliable signal given from wire to first cylinder.
But as to read at beginning after changing the last "old" cable between coil and dstributor breaker point everything was ok, but only before heating the motor up on normal temperature.

Just now, today one hour before same disaster. I left home to drive a short round. I had the first red dot at gauge (normal temperature) and it began and after some absolutely brutal loud bangs like a cannon my muffler was apart.
Today morning after that "scam success" I made only the possible shortest trip, half mile away and back. No time to heat up, nothing happened. Now I will let the car cool down and will see what happens after next cold start. If the problem is gone again I am on the right path I guess.

I think it must have to do with any parts who heat up during driving.

The disaster happens only after, lets say one or two miles when everything comes on temperature.
Coil and the condenser:
Both are brand new, but who knows. Coils may generate insulation problems when they get hot. The present coil is brand new, bought it two days ago at BOSCH service, especially for old cars with breaker point ignition.

will put in the old coil again and my last new condenser I have in stock.

Have electronic radio repair equipment (other hobby) to check condensers and today evening I will do an experiment. Checking the present used condenser and writing down everything I may gauge (how much µF at which temperature) and than heat it up by hair dryer or something else and see if anything of the gauged things is changing.

Aside that: My neighbour, expert in old russian cars, he is from there, did ask about the fuel pump. So I put the spark plugs out to pump fuel from the disconnected fuel line into an old beer bottle and as expected it pumps a lot and when I disconnected the fuel line there was still gasoline pressure in the line saying all valves inside the fuel pump are working good too.

And the new spark plugs face was totally black saying too rich mixture.

OK....am still thinking and searching.

Thanks for all Input.

You americans call cars female, "she". So I decide my car is not only she, she is an old witch!

Stefan

canadiantim, did run her with fresh gas from a canister by an improved fuel line using gas from canister instead of tank, no better result. aside that. The car tank is restored and free of rust or dirt. The first additional in line fuel filter just at the fuel tank outlet was free of dirt or rust, there is free flow.

In general: Yes, I agree with you, it is an ignition problem. And it has to do with temparature. As long the car is cold, no problem. After driving a while and getting hot all parts, the problem begins.
Did set in now the last brand new condenser I had in stock. the other one taken out i will do an experiment later. Did check it has capacity of 295 nF nanofarad and is good when cold. Will see what happens if i heat it up by a electric hot air gun.

The only test that might give you an answer with the condenser would involve a high Dc voltage. A capacitor meter or ohm meter doesn't duplicate the operating conditions. I feel very fortunate that I didn't blow the muffler to pieces on my 38.

Check the manifold heat riser to see if it is stuck closed causing a possible fuel problem.

Hello old216,

dont worry, aged 17 I began to learn and restore old pre war radios, you name them usually "boat anchor" radios and I own the equipment and know how to check and test condensers. Unfortunately the taken out condenser of my car is in perfect shape, even if heated up by heat gun. Everything ok with it.

Other question: a friend of mine here in germany has sometimes nasty ideas during troubleshooting, but he had the same idea as 41specialdeluxe here: Maybe something is wrong with the distributor grounding if it heats up.

Did see the workshop manual but there is written nothing about how the distributor grounding should be.
Sorry, because I had never before problems with Distributor grounding I dont know anything about it. How should it be? A ground wire aside or what? Who knows about?

...manifold heat riser is good and works

Very common for a bad condender to do that after it heats up......and a new condnser can be defective. Also important that the condenser is grounded to the breaker plate.
The same is true for the coil.

So I am a little curious here about the condenser testing. I too have been repairing radios and the old televisions for over fifty years. However I don't own any equipment that would test a condenser for breakdown with high voltage applied. What do you use for that test?

A capacitance bridge that includes a leakage test such as a Sprague Tel-Ohmike, or a VTVM and a high voltage power supply, connected in series.

old216, I own a small device used by german telekom to check telefon wires and/or condensers under high voltage conditions. A small box with a rod to turn, a glow bulb and a gauge. You connect the part to that box, turn the rod and a small generator produces high voltage (up to 500V) to check the part you want to test. if good, nothing happens. If bad the glow bulb will glow and the gauge show it. Have a big glow bulb 230 Volt DC too. The test resultut of both is about good or bad insulation. If the condenser is good, it gives a short light effect during loading the condenser and than is again dark, no light. If bad, it will glow constant. Using that since decades and that gives a reliable test result. Capacity can be checked by modern electronic multimeters.

Back to the distributor question: How the distributor or breaker plate should be grounded? Is there any additional wire to connect it to the engine block?
But next step must be to repair my exploded muffler. To run the car with loud thunder tank sound would end with police interrupting my work and real trouble

germanchevy,
thanks, that is very interesting.

Stefan:

Check your distributor vacuum advance. I'll bet it is not working. Stuttering and backfiring both point to timing issues and a leaking vacuum advance can cause both problems.

Good morning Mike Deeter,

sorry, bet and lost. The vacuum spark control works perfect and set the timing earlier as it should do.

Please let me return to the question: Should there be a ground wire between distributor and motor block?
Nothing there at my car.
Most of you say it is an ignition problem. I agree because when the motor runs good (as long cold) I get a constant strobo light signal saying 1st cylinder works perfect. If motor warms up and the damned stuttering begins, there is no more constant strobo light anymore, only time by time saying the 1st cyl. does not fire all the time. A clear indicator that something is wrong at ignition. I made everything new but as written before, and 41specialdeluxe recommended "check distributor grounding". Maybe grounding gets lost when motor heats up.

Again same question: How the correct grounding should be? A ground wire from distributor to block or what else? Can anybody help me tu understand what I should search for or what I should add (a ground wire?)

There is no actual ground wire from the distributor and engine block, the points and condensor ground through the distributor body. Clean where everything mounts on the points plate and where the distributor mounts into the engine block.
The coil can also give your problem, when it heats up the internals expand and short out either within the windings or windings to the case.
Tony