I've been having very slow turnover when starting my truck (foot start). When warm, it won't start. It's a 235 12v, has a new battery, new adjustable voltage regulator and the alternator has checked out. Before pulling my starter and driving an hour to a reliable shop.... What does this resistor do? It's connected to the coil and the starter. Could it be the culprit? Don
Housekeeping (Moderator) Making a Stovebolt Bed & Paint and Body Shop Forums
The resistor is for the ignition coil when running. It should be bypassed when the starter is operating. Before you do anything else, get a multimeter out and measure battery voltage when cranking. Have to ask the question re: the battery. How new is new? No guarantee that it's still up to snuff to turn the starter over at the proper speed and still provide enough voltage to fire the spark plugs. Could be the starter as well.
Kevin Newest Project - 51 Chevy 3100 work truck. Photos [flickr.com] #2 - '29 Ford pickup restored from the ground up. First car '29 Ford Special Coupe Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
If the battery is new and has a full 12v charge, the engine should spin over rapidly and without difficulty.
The usual admonitions about clean , tight, corrosion free connections apply.
Did it spin over normally and now doesn't?
The starter could be worn out, especially if it doesn't do anything when hot but spins up when it cools off.
1939 Packard Standard Eight Coupe (The Phantom) 1950 Chevrolet 3100 (Ol' Roy) 1956 Cadillac Coupe de Ville (The Bismarck) 1956 Cadillac Sixty Special Fleetwood (The Godfather) 1966 Oldsmobile Toronado (The Purple Knif) 1966 Ford Mustang (Little Red) 1964 Ford Galaxie 500 coupe 1979 Ford F-100 1976 Ford F-150 (Big Red) 1995 Ford F-150 (Newt)
The resistor is supposed to be wired in series with the ignition switch and the coil. It's there to control the current flow through the points and keep them from burning out while the engine is running. It's supposed to be bypassed with a terminal on the side of the foot start switch during engine cranking. Here's why- - - - - -
The normal output voltage of the charging system, either generator or alternator, is around 14.5-14.7 volts when running against a fully charged battery. During cranking, especially in cold weather, the battery voltage can drop as low as 10 volts or slightly less, due to the load the starter puts on the battery. To assure the ignition system gives a good spark during cold cranking, the factory installed a coil that functions- - - -you guessed it- - - - -at around 9 volts.
To keep the points from burning due to excessive current during normal running, they installed a resistor to drop the voltage at the coil to 9.5-10 volts once the engine gets started and the charging system kicks in. Unless the resistor can be bypassed during cranking (especially cold cranking) there won't be enough coil output to fire the spark plugs efficiently.
In about 3- - -2- - - -1 seconds, somebody is going to chime in with some advice to "run a coil with an internal resistor". Ignore them!
The resistor has nothing to do with cranking speed- - - - -that's controlled by the condition of the starter, the size of the battery cables- - - -and of utmost importance, the condition of the ground circuit from the starter back to the battery. All the cable connections, both from the battery to the starter, and the circuit back to the battery through the engine block and frame- - - -must be clean and tight. Don't guess- - - -disconnect and clean every connection, both hot and ground. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
An easy first step in troubleshooting a slow cranking problem.
Engage parking brakes. Place transmission in neutral. No not turn ignition switch on. Take a long screwdriver and press in the starter motor switch (red arrow) for about 3 to 5 seconds. The starter motor should run very fast (whine).
Last edited by buoymaker; Sat Dec 31 2022 01:43 AM.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
Cable condition as stated already along with cable size, 6 volt systems work best with 0 or 00 size cable, 12 volt conversions can go up to a 1 or maybe 2 gauge if everything is in good shape. Battery ground should go to the engine block then the frame and cab, block first to insure the most voltage for starting. You can not have to big of a battery cable, positive and negative should be the same size. Starters are not complicated, pull it apart and clean it up yourself. Brushes and rebuild kits should be available online, simple tools, multimeter, and shop manual will get it done.
Thank you for the great and thorough suggestions. I will try every one of them.
As a retired guy who's playing with his 1st stovebolt, I have had quite a few questions. Some of you are there for me over and over. Thank you very much. By now, you are a trusted source of information that helps keep the frustration out of the hobby I enjoy!
Thank you for the great and thorough suggestions. I will try every one of them.
As a retired guy who's playing with his 1st stovebolt, I have had quite a few questions. Some of you are there for me over and over. Thank you very much. By now, you are a trusted source of information that helps keep the frustration out of the hobby I enjoy!
Don
I often wonder how many folks new to these trucks would still be dead in the water on how to fix them if this site did not exist. I'd bet the number would be staggering.
