First I have a 48 3100 with a rebuilt 60 (or so) full flow filtered 235. I ran the numbers years ago and it is an early 60s car engine. I have trouble starting it but it runs real nice when running. I converted it from the floor button to a key start. Not many miles since rebuild. It is still 6 volts and slow to start. Like the starter doesn't want to turn it over or the engine is so tight it struggles. I have a 216 flywheel and matching starter. I have two starters - one is rebuilt and the other was checked out good. The battery is an optima red top. Battery cables are new (2 gauge), ground is to the starter base, and do not heat up when starting. This starting issue worsens after it is shut off. I believe the generator is working, the regulator (new) works, and my wiring (new harness) is good. I just don't get it. I ran the tests that I received from Nate. Thank you Nate. What help or suggestions do you have? Many thanks
6 volt, the battery cables should be 00 size, not 2. Both the ground (attached directly from the battery to one of the starter bolts) and the positive (attached directly from the battery to the top post on the solenoid).
I thought I could get by with 2 gauge. They weren't heating up? I could not figure why the starter was not spinning faster. Thank you for the responses.
If the wires aren't heating up maybe they are OK. With the help of someone to turn the key for you, check each component and connection in the high current system from the battery to the starter motor and back. Using a digital volt meter, measure and record the voltage between the positive and negative posts on the battery. Have your helper turn the key to start. Measure and record again. Now measure and record the voltage while cranking at each of these points: Battery positive post and positive cable at the battery. Battery negative post and negative cable at the battery. Battery positive cable at the battery and battery positive cable at the solenoid. Battery positive cable at the solenoid and the center of the solenoid bolt it attaches to. Center of one large bolt on the solenoid to the other large bolt on the solenoid. Clean spot on starter case (use a little sand paper to get bright metal) and center of the bolt that attaches the ground cable to the starter. Center of the bolt that attaches the ground cable to the starter and the ground calble near that bolt. One end of the ground cable to the other. And finally, from the ground post on the battery to the ground cable at the battery. Let us know what the readings are. If any of these measurements (except the first two directly across the battery posts) are more than 1/10th of a volt they are suspect.
Thanks Bill. I will get back to you as soon as possible. I have some family issues to resolve in Dallas. Thanks again
6 Volt Cranking The first thing I thought was : wrong gauge battery cables . Agreed , the next thing is ti test the battery voltage whilst cranking it , it shouldn't drop much at all with an Optima battery ~ once they're allowed to run down , getting them back to fully charged can be a hassle ~ ead up on the proper charge rate , I don't remember what it is . Yes Skeeter , the ground cable should be attached directly to the engine or tranny but if your engine cranks easily , you're O.K. for now ~ when it begins to have starting issues , fix this first when you replace the battery cables with # 1 or 0 gauge ones .
Yeah, this is an old thread, but... I'm planning my electricals out. Not finding "0" gage battery cables, but did manage to find some 1s on eBay. Positive will go from Battery + to starter. Tap from starter to feed the rest of the truck. (One big lead to the fuse block, I'll be running a Voltmeter not an Ammeter.) Ground Cable will go from Battery - to convenient spot on engine block or transmission. Ground strap from convenient spot on engine block or transmission to frame. So here's the questions -- what have y'all found to be "convenient spots"? Would love to see your pics. Also, should the alternator lead run back to the fuse block, the battery, or + terminal on the starter? Thanks!
Battery Cables The alternator wire should be heavy gauge and run unfused directly to the hot terminal of the starter . NAPA Etc. can always order in the cables you need , you just have to convince the boob behind the Counter to OPEN A BOOK . # 1 gauge should work fine. Where to connect the ground cable depends on where you place the battery .
You can also go to a farm tractor shop or store or even a shop that sells only to the big rig trucks and get the cables you need.
You stated it's a freshly rebuilt engine and both starters check out to be good. Has the engine ever started quickly since the overhaul? If it still has the rope main seals and the pistons fit tight then it may just need miles on it. One way to check this is to use a 12v battery which is a bit more involved with your truck with a key start on it. I would FIRST remove the main 6v feed wire from the stud on the solenoid, this protects everything in the truck from gas gauge to light bulbs. Remove 6v battery and set 12v battery in box and hook up cables. If you don't need to start it but just spin it over use a jumper from the battery cable post on the solenoid to the terminal that activates the solenoid. Leave switch OFF. If it spins fast then it's most likely just tight from being fresh. If you want to start then set 6v battery on floor beside battery hole and run jumper from positive to main feed wire and from negative to ground. 12 or even 14 gauge is plenty for the jumper wire size. Now all the truck is 6v except for the starter. 12v won't hurt it but will put it on steroids. You can start it and drive it to put some miles on the engine and then switch back to 6v all around. My 37 Buick has had a 6v starter (and horn) on 12v for 0ver 30 years. Probably would do 30mph on the starter and horn sounds like something that should be on rail road tracks.
