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Stalling 1938 Studebaker? Any ideas?


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Stepping back for a break is good, gives you a chance to relax the ol’ brain thinking process.  I’m going help it along with a small glass of inexpensive wine tonight (no, not Boone’s Farm) to help me🥴.  

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a) I prefer Capt. Morgan 100

b) Meant I'd just check if another carb would act different, not to go unoriginal permanently but would need the flange size. Don't have many one barrels.

c) Corollary to Murphy: what ever was worked on last, is usually what is going wonky now.

d) Always pack your own parachute.

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Swapping out a carb is a good way to melt a piston..........I have seen it several times.

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Had a problem like this on my 1928 Graham (drove me crazy for almost a month, doing everything you are doing).  Do me a favor, pull the fuel line, just before the fuel pump (check valves in my fuel pump).  Attach a hand (bicycle) tire pump to the fuel line.  Hand pump air back to the tank. you should hear air bubbles in the tank, if not, something is plugged.  Compressed air also works but my compressor is noisy, and I did not want to chance blowing off my fuel line at the tank.

 

The Graham would idle all day long, I would drive about a mile or two (35-45mph) and fall on its face, it would run, but not enough to drive home.  The next day it would start all over again, almost drove me crazy.  I bet I rebuilt my fuel pump 10 times, I was positive it was a vacuum leak in the pump seal.

 

My fuel line had a pressure resistance, it broke free and then started to bubble, hooked the gas line back up, and it has been running great ever since.  Guess I should clean out that tank....

 

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12 minutes ago, Graham Man said:

Had a problem like this on my 1928 Graham (drove me crazy for almost a month, doing everything you are doing).  Do me a favor, pull the fuel line, just before the fuel pump (check valves in my fuel pump).  Attach a hand (bicycle) tire pump to the fuel line.  Hand pump air back to the tank. you should hear air bubbles in the tank, if not, something is plugged.  Compressed air also works but my compressor is noisy, and I did not want to chance blowing off my fuel line at the tank.

 

The Graham would idle all day long, I would drive about a mile or two (35-45mph) and fall on its face, it would run, but not enough to drive home.  The next day it would start all over again, almost drove me crazy.  I bet I rebuilt my fuel pump 10 times, I was positive it was a vacuum leak in the pump seal.

 

My fuel line had a pressure resistance, it broke free and then started to bubble, hooked the gas line back up, and it has been running great ever since.  Guess I should clean out that tank....

 

 

I agree totally! This was brought up mid-way of page one of the thread. I also had the same identical problem on a 63 Impala with a 283. I had a crack in the rubber hose and I started to suck air in with the fuel under a load. 

Edited by John348 (see edit history)
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I had a similar problem with a Jaguar XK 120. The car had a brass screen filter at the gs tank, where the line to the carburetor attaches. The filter had a coating of a shellac-like material. Compressed air cleared it enough to run properly. However, for reliability, I had to drain the gas and clean filter and tank.

Phil

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Graham man. I took line off between electric pump which is near tank and turned it on. Fuel ran very well. Rebooked the line then took of off just before carb and ran it again, and again great fuel flow. I’ll give the line a try with air and leg all know how it goes. I believe I will have to do it without the electric fuel pump in line as trying to push air backwards will not be good for the pump. 
Thanks 

dave s 

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So, the carb was rebuilt just as part of your maintenance?

I don't suppose this is when your troubles started.

 

I had an old Jeep once that did something similar way back when.

I followed the hard line and along the way was a coupler. I opened that coupler and there was a small pebble in the line there that acted like a valve.

Idled fine but as soon as there was fuel demand this pebble would pull up into the next section of line but wouldn't fit and would effectively shut down the fuel flow.

Hard to say how that tiny stone made it that far.

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Dave, hopefully your head is not spinning at this point.  The suggestion to use a bicycle pump to force air through the fuel line back to the tank sounds good.  As a low pressure test system and no noise to distract from hearing the results should be helpful.  
 

My overnight head scratcher episode  came up these ideas:

1. Your electric fuel pump has a gallons per minute (GPM) rating I would assume.  Let’s say it’s rated at 2 GPM.  If you turn the pump on and feed the gas output into a container, after 30 seconds the container should have about a gallon of gas in it.  If it has something like a half gallon then there is a good possibility that the fuel pickup in the tank has a problem like a partial blockage or some other problems with hoses or fittings leaking. (You have to be pretty accurate with your timing device for this flow test)
 

2. This idea is based on your comments about the car feeling like it’s pulling a load.  Is it possible your fighting stuck brakes?  You have cable type emergency brakes, are the cables stuck?  This would bog the car down if they are.  Also, your Studebaker has the hill holder feature, is this system malfunctioning?  If it is it could apply the brakes and you are trying to overcome it when you are driving. And a long that thinking, is the master cylinder not releasing causing the brakes to drag?  Again the engine would be fighting the brakes feeling like it’s lacking power.

 

So that’s it for now.  Good luck!

Edited by TerryB (see edit history)
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Please hold on. Let’s not anyone get their underwear in a bundle over my problems, please. I appreciate any and all suggestions and based on what I’ve already tried or have ruled out as a possibility I may or may not try these suggestions right away. A very good person that knows cars backwards and forwards suggested to diagnose the problem then fix it. I will post a history of what the problem is and how it started shortly. Thanks for your help and please don’t stop trying. 
dave s 

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TerryB great idea about the electric pump. It’s a 4 gallon per minute pump. I’ll try it and also blow out the line first. The hill holder has been removed long ago as it leak badly and was not available at rebuilding time. Brakes are free and rolls easily in neutral when I have it out to test. 

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I have been helping Dave to the extent possible by phone. Offering suggestions of things to check. Unfortunately, ignition or fuel problems can be easily confused and hard for many people to determine what system is not functioning correctly and causing their problem. So the skill set of the person observing, and attempting to establish what exactly is wrong and offering help remotely are often times of limited success. Observations I would make in seconds in person can be hard to explain in emails, or over the phone. Limited tools, limited time, and a bunch of other variables make fixing a car on this forum, by email, or telephone add to the complications of getting to the core problem. With all the testing, parts replacement, adjustments, and possible other pre existing conditions that have been applied to this car.........I make the following observation.

 

Its time to start over from step one. Pull the plugs, do a wet and dry compression test. Then manually bring the engine up on top dead center, check the valve timing, as well as the ignition timing, position of the distributor, and static timing inspection. If it all checks out good, I would then start the engine, and check for vacuum leaks. I would observe the car and it’s hesitation or running problem. Then I would use a oscilloscope, dvom, and five gas exhaust  analyzer to determine if it’s ignition or fuel related. The KV test of the secondary generally will quickly indicate where the issue is. Usually only two or three percent of the time is a running problem take more than fifteen minute diagnosis. Unknown modifications done to the car, and poor workmanship and repairs done over the years also offer up as a wild card on many cars. Basically, we are limited how much help we can offer Dave. Certain times there is no substitution for a good auto tech that is hands on, on the vehicle having issues. My best guess is that Dave is at the limits of help we can offer home without one of us actually standing there helping him. If he were just a few hours away, I would just drive over and fix it for him. 
 

Dave......time to move to Florida.......better weather, and you will be close enough to where I can just run over and fix it for you. Keep at it.....you will fix it. 

Edited by edinmass (see edit history)
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Posted (edited)

Car came out of a barn in PA after 43 years. 
Rebuilt engine, trans, rear end, brakes, electrical, generator, carb, put seat covers on it. Buffed out paint. 
Car is a daily driver. I’ve put 7000 miles on it in last three years. It is not stored in winter I live in SC and weather is good year round, no snow. 
Took the girls out for a ride and all was well. 
Next day took them out and five. Mikes from home it seem to start missing. Turned around and by time I got home it was bogging down. 
I figured is was points or plugs so changed points, plugs, condenser (tried 3 different ones so far) rotor and cap. New in line fuel filter. Checked all the wires and firing order - all ok. Hood blue/bright white spark at plug. 
Still ran bad. 
It was suggested the coil could be shot so got a new one ( never hurts to have an extra anyway) still runs bad

It was suggested the electric fuel pump was bad, had an extra so switched it out. 
still ran bad. 
It was suggested the line is clogged so I took line off between electric fuel pump and mechanical fuel pump and fuel flowed very well. Did same test between mechanical and carb and fuel flowed very well 
It was suggested vacuum was bad, could not see distributor turn (automatic advance turns distributor up to 12 degrees for spark advance) so got a new diaphragm and out that on. Still runs bad. 
It was suggested carb was clogged. At this point I’m grabbing at straws so had the carb rebuilt by a local guy that does nothing but carbs. His opinion was it looked ok but seeing I already had kit might as well soak it over night and rebuild it. Still runs bad. 
It was suggested heat riser may be stuck. This was something I never gave a thought to. Checked it and found there is supposed to be a coil type spring on it and a counter weight on opposite side of intake. No spring, I don’t remember if it ever had a spring. So I don’t know if weight is automatically closing riser or opening it. Wired it in opposite direction it was in and it still runs bad. Guy feeling is the heat riser plate or valve is not even in the manifold. Don’t know how to prove that unless I just have to remove carb to see. 
Today I plugged the vacuum for the wipers. Put a T in vacuum line to distributor and ran a hose into the cabin so I could see vacuum readings while driving. 
At idle it is 14 

Start to accelerate it is 15+ 

Accelerate to about 7 -8 miles an hour and it drops to 5 to 6. 
Got back to garage looked down carb and brought to high rpm’s fuel was spraying very well. I know that could be different under load but wanted every one to know what I’ve done. 
 

I may just be stubborn headed but I still think it is advance problems but I don’t know how to prove that. The distributor can only go in one way their is no advance adjustment on this distributor per the shop manual. 
 

I am not a full time mechanic, I’m a retired ( thanks to C19) computer service bureau ( did magazine fulfillment) owner that has always worked on cars. Rebuilt Austin Healy, MGB’s, a 49 Ford F3 pickup, a few pickup trucks engines that we hauled my daughters horses all over the country with. So I somewhat know what I’m doing but also smart enough to know I’m a dummy when it comes to these things. That is why I ask for help. If I was back home in Chicago or our previous home in Lexington KY I would have 5 guys in the garage with me and I’m sure they would have this fixed. We moved here three years ago and up until the C19 I was busy at work and rebuilding the house we bought. I keep telling my wife we bought the property they threw in the house. She loved the property so what’s a guy to do. I haven’t had the time or opportunity due to the pandemic to meet any car guys here. So you all very generous people are my support group. Please keep helping me. The pups want to go for a ride, my wife wants some piece and quite and I want to drive my car!  I will buy a cold drink of your choice if and when we can meet in the future as thanks, even if your idea wasn’t the solution. 
Thanks I do appreciate it. 
dave s 

Edited by SC38DLS (see edit history)
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Posted (edited)

Ed I may just put it on a flatbed and haul it down there. It would be a ball to see the cars you get to have fun with and a heck of a thrill to have someone of your skills work on the beast. 
I will never give up on fixing it. Only fun I have anymore with this broken down wreck of a body. 
dave s 

Edited by SC38DLS (see edit history)
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I took the fuel line and used compressed air to back flow it into tank, heard the bubbles and then let the fuel flow back it came out with out any debris and the flow looked the same. I do not think I have a blocked line. 
 

 

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Ed, I think you are right about it’s time to get this to someone who either has this equipment

( Then I would use a oscilloscope, dvom, and five gas exhaust  analyzer to determine if it’s ignition or fuel related. The KV test of the secondary generally will quickly indicate where the issue is) really knows what they are doing, preferably both!  
dave s 

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One more comment from miles away:  14 inches Hg at idle is way, way too low (unless you're in the Rockies) for this engine--should be 18-20.  Easiest cause would be a vacuum leak.  Shut off the vacuum feed to the wipers for now (a leak in the motor itself or tubing thereto would cause low vacuum), check vacuum at idle again.  Then try an aerosol oil or even Brakleen at the intake manifold ports.  If idle steps up or vacuum reading improves, there's your leak.

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George, I gave him instructions on checking for a leak two days ago. Including using a special tool that’s “top secret “. 👍

Edited by edinmass (see edit history)
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Grimy -I have plugged the wiper vacuum.  The setting  is one of the things I have been trying to find out what the setting should be at idle and at higher RPM.  Ed has told me how to check it but I need to get the spray to check.  

Ed you beat me to typing this. 

dave s 

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22 minutes ago, edinmass said:

George, I gave him instructions on checking for a leak two days ago. Including using a special tool that’s “top secret “

Is that a tool that goes "sshhhh" when you find the leak?  I remember what you recommended and that Dave didn't have the Official Lotions & Potions for the job.  Other ideas: Late timing from wrong dwell?

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Ok I did Ed’s super secret special tool under the penalty of excommunication and death if divulged yesterday and that did not change anything ran the same no rpm change. Just did the vacuum test with the spray all around head and manifolds also bottom of carb and wiper vacuum where I plugged it. No change in vacuum reading or rpm’s. 
I have one more place to check what the vacuum settings should be just waiting for a return call

dave s 

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TerryB- I did check it but to be honest I have to question if I am doing it correctly and/or using the right mark on the balancer. 
I will try it again. I have a 12 volt timing light so hook the power up to the wife’s car and the plug wire to the 38’s #1 cylinder. So that should work I think. 
 

 

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11 hours ago, SC38DLS said:

At idle it is 14 

Start to accelerate it is 15+ 

Accelerate to about 7 -8 miles an hour and it drops to 5 to 6. 

 

If you then let off on the throttle does it quickly jump back to 14 to 15? Or does it stay low and creep back up?

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Posted (edited)

Frank it jumps back immediately. Also when it stalls it starts to come back by that I mean it is jumping between 4 and about 7 or 8. 
 

I guess that says it’s not a vacuum leak and more like timing??????  Or advance problem 

Edited by SC38DLS (see edit history)
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Could the secret to my success be timing? 
The white mark is about an inch to the right (facing engine from front ) of the white mark (IGN mark) when it is running. Tried to post video but can’t 

 

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At this point I'd suggest pulling the valve cover and find TDC (top dead center) by centering the cyl #1 valves (1/2 way between exhaust close and intake open) or just use a endoscope in the #1 plug hole. Timing marks have been known to be off.

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Posted (edited)

Padgett - I would love to pull the cover but I t’s a flat head 6 cylinder 1938 - no valve cover! No endoscope either. 
 

I got the timing on the mark as close as these old eyes can see it ( that’s why I put chalk mark on it) and it runs much better but not all the way there. It did backfire once when I had it out. 
I had timing light set to zero  advance on the dial on back of light. Do I turn the distributor more or turn it back a little ?  Or should the light be set on some advance number and reset timing? 
 

just thought of carb adjustment needed? 

Edited by SC38DLS (see edit history)
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If the spark plug for #1 is centered over the piston in a flathead, it is easy. pull the plug and drop a straight rod considerably longer than the stroke in. (Do NOT use a shorter rod). When the most is pushed out & centered is at TDC. Or can use a flashlight and a mk 1 eyeball. Then you know.

 

BTW would expect initial timing to be in the 4-8 degrees before top dead center range. Vacuum advance is mainly for MPG. Some VWs had no vacuum advance. Should be in the tune-up section but the higher the octane of the gas, the more advance you need (burns slower). I suspect 1938 gasoline had a lot lower octane than now (dunno what Ethyl was).

Edited by padgett (see edit history)
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Idle speed should be about 500 RPMs when checking timing too.  I don’t see it in the write up but I expect the vacuum advance should be disconnected and the line to the carburetor plugged?  I’m not familiar with setting Studebaker timing with its movable distributor.

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Posted (edited)

I forgot about the vacuum being plugged. Like I said before memory is definitely going. 
Padgett that’s the way we always did the flat head -  I long straw was what we use. 
Get it close then put car in a higher gear and rock it one way or the other until it’s at top dead center. 

 

edit - I’m so confused with all thrown at this I should have said V8 and not a flat head. 

Edited by SC38DLS (see edit history)
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Worked for a DOHC Jag also. I just put a breaker bar on the crank bolt.

 

Just looked it up and gas in 1938 was about 72 ("anti knock index") octane. Today we have 87 PON (pump octane number - about 83 research). Can anyone make a proper comparison, then to now ?

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I would HIGHLY recommend verifying the cam timing somehow, and also verifying what the ignition timing is RIGHT NOW before moving the distributor. This ran fine one day, and then it didn't, right? Who could have moved the distributor? If the cam timing, the ignition timing, or both are way off, that is a huge clue.

 

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Bloo. I have no idea how to do that unless you are saying I need to see if there are marks on the gears that line up. The timing is way off with a timing light based on the pointer and where mark is when running. The mark is almost an inch before the pointer again when running at idle. Shouldn’t it be right on pointer or very close to it ? 

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On the flathead you can make a cheap TDC gauge with a piece of dowel rod with some sharpie markings every 1/4”.  The dowel has to fit down the spark plug hole and hit the top of the piston without interference to work.  I used to take out all the spark plugs so I can turn the engine over by hand when I’m zeroing in on TDC and turn the vibration dampener to find the top of the piston travel (compression stroke).  Then at TDC see where the points are opening and go from there. 

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1 hour ago, SC38DLS said:

 t’s a flat head 6 cylinder 1938 - no valve cover!

Of course it does, it is just on the side of the block, and sometimes two of them. You have to remove them to adjust the valves.... Sometimes calles Side Covers, but you don't adjust the Sides.... English, what a language....😆

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  • Peter Gariepy changed the title to Stalling 1938 Studebaker? Any ideas?

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