Flathead Blues

F

freddybush

Junior Member
Need help with my Flathead! I finished my coupe in 1993,and have driven it with no problems until 2013. I have a 1935 Ford 3 window coupe with original flathead motor that I converted to 12volts, Mallory dual point distributor and hydraulic brakes. I felt these changes would be acceptable for safety and reliability.
Here we go. My wife and I decided to take the ford into the foothills of California near our home. Ford ran great as always till we decided to stop and get a bite to eat, we were up around 5,000 ft. As we were driving down the hill around 50 mph the ford started missing really bad barely able to stay running. I pulled over and checked the fuel pump and there was gas around the top not bad but gas so I tightened the bolts around the pump and figured that would solve the problem. I started the ford sounded fine and proceeded down the hill and after a few minutes it did it again. My Dad built the ford for my 16th birthday and connected the tail lights in January of 1970. I have experienced vapor lock and this was not like vapor lock. Anyway I let the car sit for a few minutes even though it was not hot temp was around 170-180. I made it to Jackson and decided to have it towed home.
I felt the problem was fuel so I replaced the fuel pump and thought that would take care of it but I was wrong. I then thought maybe its the carburetor so I rebuilt the stromberg, and again it would run great then do it again. I put another carburetor and it would run for a while and then do it again. I felt I had eliminated the carburetor and the fuel pump. Getting back to the vapor lock sometimes I would drive for miles without any problem but sometimes after starting it in the morning it would run great and by the time I would get out of the garage it would, I'm going to say starving for gas. What I'm saying is it will do this cold, warm or hot.
Ok, I went to start the ford one morning and as I positioned the switch to on I thought I saw the wire behind the switch move and when I reached back to check the wire it was totally loose nut had fallen off. I have to say I was very disappointed in myself for not checking the possibility of a bad electrical condition but was also happy when I found this. My thoughts were, "this makes sense, going down the hill or driving on rough roads the round electrical connector on the back of the switch would only provide power to distributor and components when touching. I wish I could say this solved the problem but I can't.
I thought maybe something is blocking fuel, so I changed the fuel filter, and ran the fuel line into a bucket just to make sure there was nothing coming up the fuel line, still did it. I also jumped the ignition switch to make sure it wasn't a faulty switch but still did it. Also checked the fuel pressure and that was fine and getting plenty from fuel pump. At this point I feel I have eliminated the fuel side of it.
I started thinking it must be electrical. First I checked all my connections and they were tight then I purchased a new Mallory cap. rotor, points, condenser, coil and resister for coil. Still have not solved the problem. I can go out and start it and it will idle great for 15 minutes and then die. I can drive it for miles and run great and then just die. Let it sit for a while and it will start like nothing is wrong. You just don't know when it is going to do this, how frustrated do you think I'm? I don't know what to do? I even changed the fuel pump plunger.
I'm so sorry for this long sad letter but I'm hoping someone will suggest something I haven't done yet. My little ford has ran so well up till this and there really is no one around my area that knows anything about flatheads anymore. Any help greatly appreciated.
 
When the engine dies, immediately check for spark at the plugs. This might give a clue from which to begin diagnosis.
 
Here I go again.........Try a Bosch 'blue super coil' Bosch pt # 00012. This coil has
an internal resistor so you jumper around your stock resistor. The electrical charac-
teristics of this coil fit the demands of a Flathead perfectly. I am thinking that since
you are now on 12 volts you have switched to neg ground as well. Be sure the neg pole of the coil is attached to the distributor.
Charlie ny
cas5845@yahoo.com
 
In my opinion this is the typical problem with these so called updates or improvements. This makes finding the problem difficult as you are not looking
at standard known symptoms. The gas on the top of the fuel pump described,
is that still happening? As suggested by Charley check the spark from a plug to
GROUND, not a plug and see how that looks. A nice crisp blue spark 3/8 to 1/2" long is what your looking for, a fuzzy little yellow spark isn't strong enough to fire and is
blown out like a candle from compression. Sorry I can't help you. I have a lot of
old Fords that have been running on 6 volts for 8o years and still run prefect. I c an get in any one of them and drive over a 1,000 miles with no fear of a brake down.
A 6 volt alternator makes the electrical system a little stronger for lights and GPS.
I'm not beating on you for the 12 volts but more of a warning for most people that
read this "update nonsense" and think it's a must do. G.M.
 
It does sound electrical. But need more info. Do as JWL said, immediately it quits, get out there and check for good strong spark. This is your first step. Report back with your findings.
Gonna sound like a broken record to regular readers here.
For reliability, you can't beat a stock (upto 1948) Ford ignition, in my experience, the Mallory replacement is not an upgrade, damn things haven't got a flathead advance curve in them, it's a sbc curve. It's also mechanical advance only, the Ford one has a vacuum brake for better timing control.
I'm not sayin the Mallory is your problem because it's a Mallory. Just making you aware that there are much better choices. Yes they often run "fine" but a swap to a stock Ford ignition will make it run fan bloody tastick!
The Mallory caps are ok though.
Rant over,
Bosch Blue coil is good.
Check your spark when it quits, nice 3/8-1/2" blue one is what you need. And report back.
Good luck,
Martin.
 
One thing he said was that he had gas around the fuel pump, the only time I have seen this is when the car had an electric fuel pump and it would pressurize the fuel pump and if it all was not well ( top bolt or screws around pump ) it will leak. Check for an electric pump and plugged filter under car.
 
"I thought maybe something is blocking fuel, so I changed the fuel filter, and ran the fuel line into a bucket just to make sure there was nothing coming up the fuel line, still did it. I also jumped the ignition switch to make sure it wasn't a faulty switch but still did it. Also checked the fuel pressure and that was fine and getting plenty from fuel pump. At this point I feel I have eliminated the fuel side of it."

This should have covered the fuel line and filter issues.
 
Could be if running the original 80 year old resistor it would heat up and pull away from a break at one of the connections, cool off and then have continuity again. GM's thought of bypassing it and using a coil with a built in resistor is an excellent one as well as checking the spark to ground after the car quits.
 
"I started thinking it must be electrical. First I checked all my connections and they were tight then I purchased a new Mallory cap. rotor, points, condenser, coil and resister for coil. Still have not solved the problem."

Think these changes would have covered that also, but that is assuming the correct ballast resister was used.
 
Aha yes But I have not been able to get gas come up the fuel line as the pump and flex line are above the level fuel in the tank. One more thought dos a 35 need a vented gas cap?
 
Believe that answer to vented gas cap is yes. At least the tank has to be vented from some source. Didn't see anything about trying it with the cap off, 34billct, that might be a good suggestion.
 
deuce_roadster said:
Could be if running the original 80 year old resistor it would heat up and pull away from a break at one of the connections, cool off and then have continuity again. GM's thought of bypassing it and using a coil with a built in resistor is an excellent one as well as checking the spark to ground after the car quits.
Click to expand...

I was just about to add the same/similar possible cause of failure as noted in post #23 of this post.....
http://www.fordbarn.com/forum/showthread.php?t=172608
 
Freddy, Since you are clutching at straws you might try looking for debris in the gas tank as V12Bill suggested.
When I ran the Fire Maintenance shop for the fire dept. we had a pumper that would act the same way. Drive any distance or sit pumping at a fire and it would shut down just like your problem. Drove us nuts ! Finally dropped the fuel tank and found a small piece of masking tape in it. The tape would gravitate to the pick up tube and the engine shut down. It would the float away until the next time.
Also, I don't know what type of condenser you have with the Mallory set up but my '41 has a stock one. It was not tight in the mounting hole due to some greasy dirt that would not allow the condenser to fasten tightly against the block. I had a Flathead on a flatbed a few times until this was discovered.
 
Its been covered here but you first need to establish that delivery is were the spark and fuel is needed at the time of the brake down ,and that's at the carb and at the plugs, lift the top of carb if its at least half full it should run ,and short the plug out ,Yellow or blue .poke a screw driver up the plug wire end .I see you are running a crab ,check the spring loaded contact inside from the wire, or remove it and place a wire through the hole .or drill a new hole .Or get the old cap and file a groove in the side and run a fresh wire from the points to the coil then coil direct to the battery ,If you do this the condenser must be connected to the wire as well .Then road test ,this will help track down the problem .Ted
 
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welcome to the 'Barn....hopefully you can figure out what your problem is and can solve it.....lots of good info from the guys .....got pics?....good luck....Mike
 
Thank you for the quick response. Just to be clear, check for spark after the motor dies? Should I connect a spark plug tester to see if Im getting fire when it misses? not sure what you mean. When it starts missing it seems if I continue to pump the gas pedal or throttle on carb I can keep it running barely.
 
My answer was also venting on the gas tank or bad coil. Once had a similar problem and the new replacement coil was also bad. Check to see if its gets too warm. Good luck. m.ralph
 
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