The Stovebolt Site Forums The Shop Area The Electrical Bay Ignition System Mystery

I explored my ignition system more today and it is still perplexing. It has been converted to 12v and the previous owner installed a new starter but used the old solenoid which had both an S and R terminal. Unfortunately, it won't engage the flywheel so I installed the new solenoid. It only has an S terminal and one of the housing screws is labeled R. If I run a wire from the R screw to the + on the coil the ballast resistor gets red hot when in the run position. There is also no voltage across the ballast resistor (12.5 on one side and .25 on the other). Thus no voltage is getting to the coil and it won't start.

If I remove the wire between the R screw and coil, the voltage increases across the ballast resistor (12.5 before and 4.6 after). Yet after running for about 20 minutes the coil overheats and it shuts down. (Side note, all voltages taken with the ignition in the run position but without the engine running)

So the old solenoid appears to be wired to work but won't engage (haven't had it running long enough to know) and the new one either overheats the ballast resistor or the coil depending on how it is wired. Any insight would be greatly appreciated. Thanks.

I'm going to assume you have a passenger car starter, not the one for the truck with the pedal start, but since you haven't identified what kind of vehicle you're working on, nor what engine it has, any advice any of us gives will be a wild-donkey guess. It's obvious that you have the wrong coil, possibly the wrong ballast resistor, and definitely the wrong starter solenoid.

With a fully-charged 12 volt battery, the ignition switch on and the points closed, there should be approximately 12.5 volts at the upstream side of the ballast resistor, approximately 8.5-9 volts at the coil + terminal, and very close to 0 volts at the coil - terminal. With the points open, you will see battery voltage at all those test points.

You are creating a dead short at the "R" terminal of the new solenoid. That screw is mis-labeled, and/or there is a wrong connector cap on the new solenoid. Get the right one, or forget about using a bypass wire.

It's pretty obvious you're trying to use a 6V coil on a 12V ignition system by the excessive voltage drop across the ballast resistor. Get a correct coil and it will solve most of your stalling/hot coil problems.
Jerry

Apologies for lack of vehicle identification. I have a 46 1/2 ton with a 235 out of a 53 Bel Air. You are correct, the foot start has been removed.

I'm unsure if the coil or ballast resistor were changed when it was switched to 12v. I did get a new 12v coil and repeated all my voltage readings with both coils and got basically the same numbers. The 12v coil dropped to 4.5 after the ballast resistor which didn't seem correct.

I haven't tried to use the new coil since the numbers were the same. I also checked the ohms on both coils and they were the same as well.

I'll have to look into the solenoid, but don't have much confidence in any of the local auto parts stores.

Something is still not adding up. Any additional advice would be appreciated.

The ballast resistor needs to be swapped for one with less resistance. Try a resistor for a 1955-61 General Motors vehicle- - -no matter which one, they're all the same. Also use a Delco-Remy 12 volt coil for the same vintage vehicles. No, I'm not interested in what you have already, new or not- - - -it's wrong. You're losing too much voltage across the resistor which leaves not enough to operate the coil. DO NOT leave the ignition switch on for more than 2-3 minutes with the points closed- - - -you'll fry the points if you haven't already. If there's more than .25 volts at the coil (-) terminal with the points closed, they're burned- - - -clean or replace them.
Jerry

Sounds like a plan and sounds pretty straight forward. Should I look into getting a new / correct starter solenoid with an R terminal or just go with the one I have an not use the connection to the coil? The points are giving me about .25 closed so they are fried. I have a new set and condenser, but haven't put them in yet, wanted to try and isolate problems so I can learn about each part as I go. I'll replace them after I update the other parts and check to make sure I get correct voltages.

Do you have a recommendation for where to get parts you indicated that will be able to answer any questions I have?

Thanks again!

Original equipment type Delco coils are on Ebay pretty regularly, and ballast resistors as well. Since the PC Patrol zaps Ebay links as soon as they're noticed, it's pointless to refer you to specific auctions.

The black phenolic solenoid cover is the thing that probably needs to be changed to get the "I" terminal back. Inside, it has a contact that touches the copper disc that transmits battery voltage to the starter windings when the solenoid engages, and drops the voltage off again as soon as the start switch is released. It's possible you might be able to swap the cover from your old solenoid and get back into business that way. Just transfer all the connectors to the old cover, and be careful not to break any of the small wires from the cover to the solenoid. The small wire that attaches to the lower terminal is particularly important- - - -it's the downstream end of the "pull-in" winding that makes the drive gear engage, and it's copper-welded to the terminal. Some rebuilt solenoids have that wire soldered to a ring terminal that's held in place by the connector stud. Good luck!

Drop me a private message if you like and maybe we can go into more detail on the design and function of the key start system- - - -it's considerably different than the pedal start setup used on most trucks.
Jerry

Jerry,

A direct link to an eBay auction is only useful to viewers in the next few weeks. eBay deletes auction information after a few weeks.

Stovebolt.com posts/threads are read many years into the future. Today's auction will be of no interest or usefulness next Spring or thereafter.

This is the logical/rational non-arbitrary reason for not being allowed to post eBay and Craig's List links outside the Swap Meet Fora.

If you post the words to search-for on eBay, that might be very helpful for future readers?

I'm aware of that, Tim, and that's usually what I do- - - -just gotta tweak the snowflakes with lace on their drawers occasionally!
LOL!
Jerry

Jerry,
We know your a tough talking, rough riding, straight shooting, son-of-a-buck grease monkey!? BUT SNOWFLAKES?! These are car guys with grease under their finger nails too. 😳

I hadn't considered swapping the solenoid covers, but sounds like it is work a look. Definitely less painful than asking at the local auto parts store. I will take a look at it once I pull the starter again to take the old solenoid off. I can take it apart since it doesn't work anyway. Yet the new one does slip on the flywheel occasionally as well, but it will turn it over most of the time.

I would be interested in seeing ebay links to make sure I am looking at the correct parts. In my quick coil search, I've seen them from $12 to $40, which seems like a big difference. Can you share links via private message? Either way, I'll probably be in touch once I get the two solenoids off.

Thanks again!

Since posting picture links is a little iffy on the site, (I can't see Photobucket at all for some reason) maybe we could take the discussion to email once you get the starter out on the bench. That old thing about pictures being worth a lot is so true! My email is in my profile, I believe, or that's something that can happen by PM.
Jerry

tneely. Hold on here. Wait a minute before you go buying anything else and wiring anything else. Lets confirm more info.
1. You have a 53 motor with a 6V starter with a solenoid mounted on it and a 12V system?
2. What kind of ignition switch do you have? Do you have the spring loaded one or just an on-off ignition switch with a separate push button somewhere?
3. Does your coil say internal or external resistor? Hopefully an external resisted if you have a ballast.
4. What is the part number of the coil you are using and what does your ballast resistor look like.
5. BIG QUESTION...ready? Have you been driving this truck with no troubles? What happened before "I explored my ignition system more today and it is still perplexing."
Also, I am not sure yet if you have a bypass* system. It is best to have a bypass system.
I will watch for your answers and help you. Lets back up here though.

There is a good write up in the tip section on 12V conversion. Do what it says. Jerry is pointing you to the bypass system with his suggestions.
Ballast resistor
Coil
Without an R terminal I don't think you can use the ballast system. Get a solenoid with an R or I (this terminal will NOT be a screw, it will be a stud with a nut.)

OOPs, sorry Jerry, you said all this in 2004. I wasted allot of ink, or bites or whatever.


Tim, it sounds like you're right on with your advice. With the engine running, voltage at the "+" terminal of the coil should be about 9.5 volts. This is accomplished by installing a ceramic-shielded resistor between the ignition switch and the coil. During starting, the coil needs full battery voltage, because battery terminal voltage drops while the heavy amperage load of the starter is present. To bypass the resistor, there is a terminal on the starter solenoid marked either "R" or "I". Looking at the starter solenoid from the rear, it's the small terminal on the left. Run a wire from this terminal to the + terminal on the coil. It will get full battery voltage during cranking, then drop back to reduced voltage when the starter disengages. If you're using the original 6V starter, the bypass terminal might not be there, so install a 12V solenoid, or a complete 12V starter assembly. Some later-model cars and trucks used a nickel-chrome resistance wire from the switch to the coil, and did not use the resistor. They have the same bypass lead from the starter as the resistor-equipped models.
Jerry
Not sure about the RED part for this guy.
_________________________

A 6V solenoid operated starter running on 12 volts will be a short-term situation. The solenoid will hammer itself to pieces due to the very violent engagement of the gear drive. It will also have a tendency to burn out the pull-in winding of the solenoid.

It is possible to mount a 12V solenoid on a 6V starter so the flywheel and the starter drive will be compatible. The starter doesn't really care what voltage it operates on- - - -the solenoid does.
Jerry

OK just wanted to be sure he didn't think 12V starter complete. The 6V solenoid not lasting seems not to be a problem anymore. Many folks running them long time, no trouble. The Chinese are using larger wire and better steel now

Thanks all for the additional information and questions. I now have the starter off again and took a look at the old solenoid. I now understand how they work, but don't think I'll be able to change the cover from one to the other (beyond my abilities at this point). Going to be a busy day at work, but will get back to this will more as soon as I can. Thanks!

To provide a little additional information. The truck came to me with a new starter yet used the old solenoid (previous owner sent the old starter / new solenoid with it after changing). The old solenoid was 4 post and wouldn't engage with the flywheel, the new was 3 post and doesn't connect to the + on the coil, but will engage with the flywheel and start the engine. The old coil doesn't have any markings on it so I couldn't tell you if it is internally or externally resisted. It did have ~2.5 ohms when tested. I bought a 12v coil that indicated it needed an external resistor but returned it because it gave me the same numbers as the old and I wasn't confident the salesman gave me the correct part.

I did reach out to one of the specialty online sites who recommended a solenoid and coil but said I didn't need a ballast resistor.

I must note again that my voltage measurements were taken with the key in the run position but without the engine running. I was told that this would make a difference.

As for the background of the truck, it sat for many years. The previous owner got it running and sent it my way. Since then I have had it running but only drove it a short ways before it overheated (should have checked the thermostat, oops). I think it also overheated the coil at that point as well but I was distracted by the blown radiator hose. The last time I had it running it just idled for ~20 minutes before the coil overheated and it shut down. The only other thing I haven't done is change the points and condenser, which I have.

Any additional thoughts please chime in. I've got a couple of ideas on which direction to go but just took the starter and old solenoid off again last night.

I will respond with a suggested fix when all my questions are answered. You did answer some. I won't keep asking them over and over. I even numbered them for you. Otherwise I can not ask follow ups and this will take forever. Your choice. We are not there and can not see, smell, test or hear it. We have to understand everything you have. Then we WILL fix you. I am NOT being rude I am trying to get your attention. You do not need any voltage or current measurements, you need the correct parts for the correct ignition system. Once we know exactly what we are starting with, we can continue. Otherwise it's still a "wild-donkey guess". You can do a ballast resistor style or not. I believe you now have a mix of each style. Not sure until more info from you. These two styles use two different coils, solenoids, wiring and possibly condenser.
EDIT: deleted two styles explanation due to new info from Tneely and we have discussed he has Spring loaded IGN SW.

I will try again, thought I answered all of them to the best of my ability with what I know. Keep in mind, the "new guy" under my name isn't because I just joined. I'm happy to now have a functional knowledge of what I have, I have no clue what other possibilities exist that everyone is sorting through to provide help. If I don't provide what you're looking for, its because this is my first time through this so if you need additional information please let me know.

1. I have a 53 motor with the correct starter. The old solenoid does not have any markings on it but it doesn't matter because it doesn't work. The new solenoid is labeled 6v and does not have an R terminal. The solenoid does mount to the top of the starter. It has been converted to 12v. I put in a new 12v battery and it has a generator. Beyond the ignition system no other components of the electrical system are currently hooked up.

2. The ignition switch is a keyed ignition on the dash, the foot starter has been removed. Not sure what you are asking with the "spring loaded one or just an on-off ignition switch with separate push button somewhere" The ignition switch has a positive wire from the battery, one back to the S terminal on the starter, and one that goes through a ballast resistor then on the the + on the coil.

3. The coil that came on the truck has no markings on it at all and I do not know if it was changed when converted to 12v. Sorry I don't have any further information, I thought it was possible to tell the difference between a 6v and 12v coil with the ohm readings. It does not indicate internal or external resistor.

4. No part number on the coil. The ballast resistor is porcelain, rectangular with a extension on the top for the bolt. It has a screw connector on each end.

5. Sort of answered in my last post. Ran great then ran rough and stalled. Once when driving (able to start again and limp back home) second time after idling and wouldn't restart. Hasn't been running since then because I have been digging into it. I'm not sure if I have a bypass system either, if you have a resource to help me determine that I can let you know.

Hope this helps you help me and gets you paste the "wild-donkey guess" stage. Thanks again for all the assistance, I appreciate it.

Thanks for the alternate wording, I understand now. I turn the key to the right, hope it starts, and it springs back to the run position.

Thank you for the two wiring options, I'll look into them.

One more question (which will show my ignorance / bliss). With an externally resisted coil, is the ballast resistor the resistance that is referred to or is there another resistor necessary.

Thanks.

The ballast IS the external resistance.
OK, understand spring loaded IGN SW.
Parts: Get a externally resisted coil I linked. Get a Ballast I linked. O'Reillys.
Wiring: IGN SW start terminal to S term on solenoid. IGN SW run terminal to Ballast. Other side of ballast to coil pos. R on solenoid to coil pos. Batt to batt terminal on IGN SW.

No R terminal you say? Run a wire from start term on IGN SW to coil pos. Another way to describe same wire: Wire from S term on solenoid to coil pos.
Keep the Start to S.

Should be no other ignition wires. May be charging wires and sometimes the big battery lug on solenoid is used to power other components.

See 1953 truck/car schematic for charging wiring. I think you and I agree not to wire all that until you get the ignition working. You can charge your battery with a battery charger while doing this stage.

Power for ignition components on the schematic comes from/thru the ammeter it seems. I would not supply power that way. I like: battery to starter switch with a *fusible link inline. What *they are, and how to size them, is all on Google.
I don't like ammeters or wiring to them. Using them as a hot terminal block is a bad idea. Use a terminal block and use a voltmeter.

Also it is very important that all components have a fuse, or in the case of bigger battery supply wires, a fusible link.
The coil will get hot and the ballast will get hot. Normal.

It looks like your 6 volt starter takes a "saddle mount" solenoid. I do not know of a 12V solenoid that fits. I'm sure someone knows. It's good to do but not necessary. Your 6V solenoid will work. As Jerry says it may not hold under many cold or hot starts.

Don't throw away any starters or solenoids. The starters are probably only available rebuilt and the core charge is $100+ !!!!

Good luck Tneely. You got this. You have kept your composure thru your trial by fire from us old snowflakes.

Bartamos, I will say that there was some directness that I wasn't expecting. After a deep breath, I jumped back in the deep end. I really can't complain when I'm getting free advice from those with much more experience than I have. Most importantly, you delivered what you promised. I now know (or at least think I know) what the problem is, how to fix it, and what parts I need. Just glad you old snowflakes haven't melted.

I've decided to get a new solenoid, my starter occasionally doesn't engage with the flywheel with the 6v one hooked up so I hope this will help. Also going to get a new ballast resistor and 12v coil. I have new points, condenser, distributor cap, and plug wires. Beyond that, there shouldn't be much more to change in the ignition system. If it doesn't work, I'll just jump back on here and blame you.

Thanks for the wiring run down. I found a 12v solenoid with an R terminal. I'll keep the 6v solenoid in case I have trouble and remember that there is an alternate wiring if I need it.

I have also seen wiring diagrams with an ammeter, but honestly that hasn't been included in my research. Since you aren't recommending one and I have a solution without it, I'll leave it out of the equation until I learn more. I also don't have any background with fuses or fusible links, but I have some time while I'm waiting on parts to figure that out.

Thanks again for all the info and the vote of confidence. I've learned a lot and gotten to practice my non-Sunday school vocabulary words!

The hallmark of a Master Mechanic is the ability to hurl profanity at a project for at least 5 minutes straight without repeating himself! Doing so in a variety of languages adds bonus points!
LOL!
Jerry

If starter "doesn't engage with the flywheel" again, we will have to get more info. There are several meanings to that phrase. Many phases on here are like that. Like "truck won't start". "Noise from headlights"

1. Solenoid clicks but starter motor does not rotate?
2. Solenoid does not "click" in?
3. Can hear solenoid spin and grinding with flywheel teeth?
4. Solenoid won't stay engaged but does crank motor some?
5. Frequency of the event and circumstance always the same?
6. Does eventually start?
7. No noise of any kind from solenoid or starter when Ign switch operated. Dead?
8. and so on.

We will do fuses and such later. Easy as pie, piece of cake.
Please post the 12V solenoid Part Number and where you got it for future searchers finding this post. That's if it fits and works, of course. Hope it's not Ebay.

You can blame me anytime you want. You will be right at least 50% of the time. Forgetfulness is the culprit. Forgetfulness is like..........something or other. I'll think of it and get back to you.

Wait, so all I had to say was that the truck won't start? That would have saved me a lot of typing.

To provide additional information. The starter gear spins just fine and most of the time will engage with the flywheel and crank the motor until it either starts or I release the key. I have cranked for as long as about 30 seconds with no problems. No slipping or problem once engaged. However, occasionally, the starter gear spins and just grinds against the flywheel so it is not engaging or not extending far enough. If I get the grinding I immediately release the key to prevent any wear of the gears. The starter is new and that gear is fine and the flywheel does not appear to be ground down or damaged. Could this be a problem with the 6v solenoid or is it something else? Thanks.

The problem is probably the position of the solenoid. It's adjustable, as evidenced by the slotted holes in the mounting bracket. The correct procedure for installing it is to push the exposed linkage into the "engaged" position with the battery cable disconnected and move the solenoid into position so the contact disc inside is engaged, then lock the mounting bolts down. The pinion gear should be fully engaged in the flywheel before the starter motor ever begins to turn. Due to manufacturing tolerances, sometimes it's necessary to elongate the slots in the solenoid mount in order to get proper synchronization of the gear engagement and motor start timing. This adjusting procedure should be done (and tested) on the bench before the starter is installed.

Once again- - - -stuff made 50-something years ago was not always manufactured perfectly, and the junk made in China these days has even less quality control. Expecting every part we buy to fit perfectly without a little massaging probably isn't realistic. A real mechanic makes things work- - - -a wrench jockey swaps parts and hopes!
Jerry

Jerry, I see what you mean about adjusting the solenoid. I see the slots in pictures. I've also read where a 12V solenoid may need it's bracket holes modified to fit. What I don't get is how you know where to locate the solenoid while on the bench. How do you get the "timing" right on the bench. Making sure the gear is fully engaged before spin. I can't find a procedure in a manual.

Clamp the starter housing in a vise, and put a pair of vise grips on the shift lever. Pull the gear to its full-forward position against the return spring. Adjust the solenoid so the contact disc makes its connection just as the gear reaches its full-forward travel. An ice pick type test light or an ohmmeter can be used to check the contact. Test the operation electrically by leaving the starter motor connection at the solenoid loose and apply voltage to the "S" terminal. Ground the large terminal that would normally power the starter motor. The pull-in winding will hold the solenoid in the engaged position and a feeler gauge can be used between the gear and the starter nose cone to check for full engagement without hammering the nose cone.

All this is "Starter rebuilding 101" for people who don't rely on rebuilders to do it right the first time. I do the same electrical check on starters with enclosed linkage to check for worn or bent parts before installing a rebuilt starter. The motor spin timing on a starter with enclosed linkage can be delayed in case of premature motor starting by grinding a small amount off the pin that the solenoid plunger hits at the end of its stroke- - - -the one with the copper contactor disc attached to it.
Jerry

I have read there is a 3/16 "pinion clearance". Is that for this situation? and where is that dimension measured? What do you do with the vise grips to "pull" the gear? Are you just operating the lever? Why do you need vice grips? Just trying to learn.

The vise grips are used on the starters with the shift lever exposed, like the one we're discussing here. Clamp them onto the exposed lever as a handle to overcome the return spring and hold the gear in the engaged position. Nose cones with the linkage enclosed are a little more difficult to time, but most problems with them are due to the Y-shaped shift lever getting worn where it engages the Bendix. If the round pivot points are worn, some rebuilders weld material back on and mess up the motor start timing.

"Pinion clearance" is the measurement that keeps the starter pinion from bottoming in the flywheel ring gear teeth on starters that bolt to the block vertically. Since the starter pinion is below the crankshaft centerline, shimming between the starter and the block decreases the tooth engagement. I spray paint a few flywheel teeth and spin the starter to see how much paint gets rubbed off, and shim accordingly. This does not apply to bellhousing-mounted starters.
Jerry

Thanks

Also trying to learn from this; is this not knowing about the adjustment need why the replacement/rebuilt starters I installed on my long gone '71 had that high pitched grinding sound on start up?

Sparky, around that time frame there were shims that went between the starter and the block. Sometimes you used none sometimes 1-2 until you got it right. That could have been the cause of your grinding.

Yes, the block-mounted starters were notorious for the drive teeth bottoming out in the flywheel gear and making quite a racket. The shims moved the starter housing down, and away from the tooth gullets in the ring gear. The simple way to check tooth contact was to spray paint an arc of the flywheel teeth and shim until about 3/4 or a little more of the tooth depth got the paint rubbed off by running the starter.
Jerry

If I'd only known then....

Thanks guys.

Thanks for all the additional info. I'm going to have to digest it a bit. I think I understand, but without the parts in front of me it is a little confusing. I know the basics on how the starter and solenoid function, but I'll have to do a little more homework on adjusting them. No use playing with old parts so I've got some time before the new ones get here. I'm sure more questions will come up as I get back to work. Until then, time to look into starters 101.