VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 1932 engine running bad at high speed

My 1932 Chevrolet starts easily, runs fine at idle, accelerate ok and run well at speed until 40 mph, when I reach 45 mph engine stall as if it`s running out of fuel.
If I lower speed to 40 mph it runs fine again, it acts like this both cold and warm.
After 30 minutes it starts to run bad even at lower speed and if road goes just slightly uphill it runs bad.

Last year I had a problem were I could only drive few miles before engine ran bad and then stopped. It was solved by replacing the diaphragm in fuel pump.
The diaphragm I mounted was a NORS part, so not neoprene, so I thought it could be bad again, so I replaced it again, still same problem.

As it feels like running out of fuel, next step was to take carburator apart, and clean it with compressed air, I didn`t find any dirt inside carburator.
I still had same problem, so toke carburator apart again, and looked very closely at all parts, and cleaned all parts with compressed air, didn`t find any dirt or other suspicious things.

A few weeks ago I went for a 45 minutes cruise, where it ran very bad for the last 15 minutes and finally stopped.
I couldn`t start it again. I was 15 minutes from home with no tools, so didn`t know what to do, but had some cold water that I poured on the coil and fuelpump.
Engine started and ran well, so I could go home, but close to home it started to run bad again.
I tried to replace coil, but still the same problem.

As it feels like running out of fuel, I have mostly concentrated on carburator and fuelpump, but could it be caused by an ignition or other problem?

Does it over heat or get hot ?? jsut asking as you say it runs fine then after time it starts to act up.

which carburetor do you have on there ??

did you pull plugs and check color and condition ??

do a once over on tuneup items and timing ?? points gap, plug gap, timing, etc...

I replaced radiator core and rebuild waterpump before this season, so overheating is no problem anymore.
Running bad at 45 mph is at any temperature, and then after 25-30 minutes it starts to go bad a lower speed.

Carburator is a W-1, but besides that I`m not sure it`s the correct W-1 for my car, but it ran well last year.
Hope someone can tell from pictures if it`s correct for my car.

Last year I used Champion D16, but before this season I switched to AC C87. I have tried to go back to the D16, but it`s exactly the same.
I think the look of the C87 is ok, se picture.

I have checked timing and valves several times, settings doesn`t move from check to check.
Timing is set at 18° and plug gap is .040".

I have seen a capacitor do this.
Wilson

Next time it starts to run bad only pour cool water on either the fuel pump or coil not both. If it then begins to run well that is probably the source of the problem.

I have had coils internally short but generally that is in hot weather and lower engine speeds. Pouring water to cool gets it to run well nearly instantly. Low engine speed and uphill load heats the coils more than higher engine speed and running on the flat.

If the fuel pump (more likely in my mind) pouring water to cool the pump will not instantly get it to start as it takes some time to get more gas to the carburetor if it is vapor locking. Also if the wafers don't seal well to the seats in the pump the fuel capacity will be reduced. Coupled to heat can produce what you are experiencing. Also the springs on the arm that contacts the cam shaft regulate the outlet pressure. If those springs are weak it will reduce the fuel flow rate and be more susceptible to vapor lock. Checking the output pressure on the fuel pump should give a clue. Small air leak at the settling bowl gasket can be a cause. The housings over the years distort so I use cork gaskets as they are much more tolerant of imperfections than neoprene.

Hello Morten.

Your spark plug photo looks like the engine is starved for gas and is running out. This is what spark plugs should look like, slightly gray to tan when the air:fuel ratio is correct:

https://www.championautoparts.com/P...maintenance/how-to-read-spark-plugs.html

My '36 Chevy recently had a similar problem. I traced it to a warped fuel pump casting that was leaking where the glass bowl attaches to the casting with a thick wire "bail" and a nut. Because of the vacuum leak the fuel pump was unable to create an adequate vacuum to operate properly. That was obvious from looking at the glass bowl because the bowl only had a tiny amount of gas in it rather than being full. I removed the fuel pump and worked the lever up and down while the inlet side of the pump had a tube connected to a small gas container. That confirmed the problem. Rather than try to straighten the casting and risk breaking it I used two cork gaskets that compress and compensate for the deformation in the casting. After doing that manually working the lever up and down instantly filled the glass bowl.

On my '36 Chevy I found that a 1935-48 Ford fuel pump diaphragm is a direct fit. Ford parts vendors sell that part individually so you don't have to buy an expensive "kit" to get one inexpensive part. There are also AC fuel filters that are a direct fit in the '35-'36 fuel pump to replace the crude and ineffective filter screen. You may find a similar interchanges for your '32.

Good luck!

Ray W

Thanks, I will pay more attention to the fuelpump again.
This weekend I will bring some cold water, and then take a trip, and try to cool only the fuelpump.

But if it`s a problem with fuelpump, shouldn`t I then get the problem with a little delay from I reach 45 mph, as carburator bowl should run out of gas first?

"This weekend I will bring some cold water, and then take a trip, and try to cool only the fuelpump."

Cooling the fuel pump will have an effect if the problem is vapor lock and the point where the gas is boiling is in the fuel pump. I have no knowledge of the '32 but I've had the same '36 pickup since 1965 and in all that time there has never been a vapor lock problem. And it's been driven long distances across some really hot deserts.

If the issue is vapor lock there are other places that gas can boil like in a fuel line too close to a heat source like an exhaust part or in the carburetor due to a malfunctioning heat riser.

On my '36 the heat riser was endlessly sticking until I made a shaft and bushings from stainless steel about 40 years ago and that totally ended that problem.

"But if it`s a problem with fuelpump, shouldn`t I then get the problem with a little delay from I reach 45 mph, as carburator bowl should run out of gas first?"

I don't know. One diagnostic observation would be to look in the carburetor float bowl when the engine quits and see if there's gas in it. Your '32 uses the same basic carburetor as my '36 and popping off the float bowl cover takes only a few minutes. Just don't lose the accelerator pump/metering rod linkage clips while you're doing it.

Don't worry Morten, you'll find the problem if you methodically check the "usual suspects". With mechanical problems it's almost always something really simple, but the challenge is finding that simple thing. When you find it you'll slap you forehead and say to yourself "How did I miss that?"

I actually drive my antique rather than hauling it around on a trailer, generally alone because most other antique owners don't trust their vehicles' reliability enough to drive long distances in remote areas. So I would suggest carrying a few spares of parts that can fail suddenly like the ignition coil, ignition points (I've had a rubbing block break off on a company truck in the 1970s), condenser, distributor rotor and fuel pump and the tools to R & R those parts.

Ray W

When replacing diaphragm in fuel pump, what is then correct position of pump arm when tightening the 6 screws?
I can feel the vacuum at inlet and pressure at outlet, and I get some fuel, but not sure if it`s enough.
Is there a test I can do with pump of the car, that will tell if it`s in good or bad condition?

yes you can do a test... use a pressure/vacuum gauge.

here is my posting where i went through a fuel pump ordeal on my 1929. talks about vacuum and pressure on the bench and on the car. 1929 Chevrolet Test Fire ONE...

When assembling this type of fuel pump I hold the camshaft arm to its full travel then tighten the top screws. That way the camshaft wont operate the arm further than the diaphram has available.
Tony

I took fuelpump apart again, and went through all parts, checked if anything was warped, didn`t find any problems.
Assembled the fuelpump, checked I had vacuum at inlet and pressure at outlet, it felt as before.
Mounted fuel inlet, tried to pump fuel by hand, nothing happend, mounted pump on engine and cranked it for 30 seconds, still no fuel in glas bowl.
Disconnected fuelline, blow air through the fuelline, disconnected fuelline at tank.
Sucked up fuel from tank with syringe, mounted fuel line at tank, sucked fuel through fuel line with syringe, mounted fuel line at pump.
Cranked engine and I got fuel in glass bowl, shortly after engine started, and now I have cruised 40 miles without any problems.

Very much the same experience I had some months ago 1932 fuel tank

Glad that it`s now running, but very annoying not to have found the exact problem.
My best guess is crud in fuel line or tank pickup, or maybe a small leak that leak my vacuum but not enough to leak fuel.
If I get the problem again I will start before the fuel pump even if I get some fuel out of pump, it has now confused me twice, and I have spend so much time on carburator and fuel pump.

did you vacuum/pressure test the fuel pump on hte engine ?? see what vacuum you go ? what pressure you got ??

No I searched forum, but didn`t find your post, so problem was solved before I saw your link, but will use it if it fails again.

Your experience is consistent with lack of complete sealing of wafers in the one way valves when dry. Any gas between wafer and seat dramatically helps them seal. One of the rebuilding instructions is to put a tiny amount of oil on the wafers when reinstalled so they are not dry when initially used.

ok link was in my post :)

glad you are up and running again

If the fuelpump for some reason don`t get fuel, will they then dry out again, or is it only a problem when new?

I know, but for some reason I don`t always get mails when there is a new post, so didn`t see it until car was already running.
If problem get back, I will try your test before and after oiling the wafers. If I get ok measurements I will look at fuel line and tank.

I did this, as it also looked most logical when looking at the parts.

The pump is part of a nearly completely sealed system. My experience is the pump wafers stay wet enough for a long time. Probably nearly as long as the glass bowl still has gas in it. Reminds me of the hand water pump on our drinking water well. After a long time if no use the leathers would dry out and you had to prime the pump.