The Stovebolt Site Forums The Shop Area The Electrical Bay 69 C10 Starter or Solenoid Problem?

Hello. I have a very strange problem with the starter/solenoid/alternator on my 1969 C10.

When cold, she turns over with plenty of cranking power, and starts and runs fine. After driving on a short trip (say 10 miles), and I turn the engine off and then try to start the truck, there is a problem. The starter barely turns over and acts as if the battery is almost dead. The engine will give a small attempt to turn over, then delay a second, and then makes another feeble attempt to turn over, and sometimes she fires up, and other times I have to roll start her.

Last time I left the engine running and put a voltmeter on the battery terminals. The alternator was charging the battery to 15 volts, and when I turned off the engine, the voltmeter showed the battery slowly dropping from 15 volts down to 14, to 13, and after some time it stayed around 12.75 volts. Is it normal for the alternator to charge the battery so high?

I also watched the ammmeter in the dash, and during the entire trip, it was showing it was "charging". Turning the headlights on did not seem to change the position of the needle on the ammeter gauge. In the past, I think the needle quickly went back to the middle position on the gauge when driving (especially during the day, and no electrical items being used).

When the truck fully cools down, there is once again plenty of cranking power and the starter spins over with authority.

Is it possible that the alternator is overcharging, and that the starter does not like getting 15 volts (after the truck has been running for awhile)?

Or, is this just a sympton of either:
1. A bad solenoid
2. A bad starter
3. A bad coil

Another tidbit of info. that may or may not be important: I think our fat cat must have crawled up into the engine bay and stepped on a plug wire.....which caused the plug to come off the #6 spark plug. And Murpheys Law applies, and the plug wire fell right on top of the starter solenoid, with the electrode facing the solenoid. So, I think that the solenoid was getting a good electrical jolt for several months before I took time to check into the problems (the engine was not running up to par, but sometimes with only one plug wire off, its easy to just think that maybe the points/condensor/plugs just need cleaning/replacing). I think the high current from the ground wire was just grounding out on the solenoid, and no damage was done.......but I thought I would mention this just in case. Dern Fat Cats!

So, thanks for any suggestions you might have.

Dwight

First your charging voltage is too high. It should be about 14-14.5 That is not causing the problem unless it has damaged the battery. Did you put a load test on the battery? The rest of those readings were normal. Next take a good look at the cables. Some of the cheap after market cables have undersized wire in them. They should be 4 gauge at least. You didn't say what size engine you have. Often someone has put the low torque starter on the larger engine. The high torque starter can be identified by a spacer between the selinoid & the terms. that comes out of the motor. A 327-350 or 292 should have the high torque starter.

Sounds like a bad cell in the battery. As George suggested, have a load test done on it.

Wrenchbender Ret.......Ok, the charging voltage is about 1/2 volt too high......is that over-charging the battery, and a bit too much, and harmful to the battery? I will do a load test on the battery to see if there may be a bad cell. However, when the truck sits for a few weeks, I will test the battery and she is maintaining about 12.5 volts. She has plenty of cranking power when she is cold, but the problem arises after she is warmed-up.

Sorry....I forgot to mention that this is the standard small block 307 V8, with a 2 barrell carb, headers, dual exhaust, and 3 on the tree. Still has the stock points/condensor (not electronic ignition). The battery cables are the good heavy duty ones, and have been on the truck the 25 years which I have owned her. (Kept clean and maintained at the battery posts. However, I have not removed the cables/wires at the solenoid/starter and cleaned in many years).

I will do the load test on the battery and let you know the results. However, why would the battery seem so powerful when cranking the cold engine, and then struggle and barely turn over the engine when warmed-up? I would think that the battery would have a bit more juice after charging for 15 minutes as opposed to a cold start with the battery down at around 12.5 volts.

I will also look at the starter and see if it is a high torque or standard. Again, the starter has been on the truck for over 25 years, and I never had this problem until recently.

Now I am thinking "valves". If the valves warm up and are not adjusted with enough clearance, then maybe the engine is cranking and an exhaust valve is not opening up to relieve pressure, making the engine hard to crank when warm? However, I thought that these 307s had hydraulic lifters, and never needed adjusting. Is this true?

Thanks for all the input.

Cletis.......10-4....will do the load test.

do you have a heat shield between the headers and starter? Mine does the same thing if I drive it a long time and the underhood temps get up there, let it set 15-20 minutes and cool down and, it spins fine again. I ended up putting a larger batt wire going down to the starter and also ended up with a new battery (mine was 5 or 6 years old).

69 Cuda......Nope,no heat shield between headers and starter. But the headers are pretty far away from the solenoid/starter. Never had this problem over the past 25 years, and the headers have been on that long.

I actually thought that the No. 6 plug wire that was resting on the solenoid was electrically heating up the solenoid as I was driving the truck, and that caused the problem. But after putting the plug wire back on the plug (definately made her run smooth again), she still does not want to turn over when the engine is warm. Also, the temp gauge is not getting hot....just stays on the cool side of normal.

All the parts are now old.....so, it could be anything from the solenoid, starter, voltage regulator, coil, or even the battery (but the battery is newer).

Do you know if the valves are adjustable on the 1969 307V8? If they are, then I still think that maybe the exhaust is heating up, and then not letting gasses escape properly, and hence the engine does not want to crank when warm.

I have no idea why but a battery with a bad cell will do that. It's not that the engine is warmed up but the battery is warmed up.

cletis......Ok, Im going to check over the battery real good. Since she has been charging at 15 volts, maybe the water has been boiling and are half dry, and could need replacing. Actually, this would be an easier fix than a bad starter.
Thanks.

The 307 has hyd. lifters. That theary about the valves is not good. Engines can tighten up when hot when they get older. Carbon in the combustion chamber & behind the rings can raise comp. & tighten up as the pistons expand. If the battery is good you probably need to pull the starter & go through it. The ignition coil would not likely effect this. Yes. An overcharging condition will shorten bat. life.

Check the battery terminal voltage during the hot start problem. If it drops below about 9 volts with the starter engaged, try a different battery. If the problem persists with a known good battery, it's time to look for internal engine problems that are causing the rotating assembly to tighten up when the engine is hot.

Cold cranking voltage with looser engine clearances should be somewhere in the 9.5-10 volt range, and you should be able to crank the engine for 15 seconds or so with the ignition disabled without a noticeable slowdown of cranking speed. My best guess is a battery with limited cranking amps and/or a compromised reserve capacity.
Jerry

Wrenchbender Ret/Cletis.......Thanks for verifying that the 307 has hydraulic lifters, so I can rule out the valve adjustment idea.

I did a load test on the battery today. Clamped on the load tester and hit the load button for about 10 seconds, and the needle on the tester showed the battery was right in the middle of the "Weak" yellow range. Before testing, she was at 12.5 volts, and after the test she was at 12.3 volts. I will now pull the battery out and check each cell for specific gravity.....I am betting that I have a bad cell, or there may be several cells getting dry (since the alt. has been charging at 15 volts).

I still dont understand the scientific logic as to why a weak battery has tons of cranking power when the engine is cold, and barely turns over the engine when warm.

Hotrod Lincoln....."Youre gonna drive me to drinkin, if you dont stop drivin that h-o-t r-o-d L-i-n-c-o-l-n"....great song...Commander Kodi, or something like that.

OK....I will measure the volts while the starter is cranking and let you know.

Holy Cow, Batman......I sure hope there isnt internal engine issues as you said. Im now actually "hoping" that I have a bad battery......a much less expensive fix.

Has the distributor timing, or points been recently worked on? Sometime when cold the engine will crank fine, but when hot will grunt while cranking if the timing is slightly advanced, or if the point dwell is not correct.

My bet is a bad cell in the battery, but if the points haven't been checked in a while, look at them and maybe the inside of the distributor cap for burnt terminals.

Roy Rodgers.....No, I havent replaced the rotor/points/plugs in several years, and havent put many miles on the truck. But thats a good idea about the timing being off, or dwell incorrect.

I will replace the battery if it has a bad cell, and if it still has the same poor cranking issues when the engine is warm, I will go to the next tests.

If you have a real load tester, one with a carbon pile variable resistor, you can take a voltage reading during a hot start attempt, and then use the carbon pile to drop the voltage to the same level and see how many amps of load it takes to create the same terminal voltage. For instance- - - -hot start voltage of 9.5 volts might convert to a 400 amp current load. That would be an excessive current draw for a good-condition starter, indicating excessive drag inside the engine.

Most "battery testers" have a constant 100 amp load built in, which is virtually worthless for any serious check of a battery's cranking capacity. They're sales gimmicks to make an already-weak battery seem really bad and sell a new battery. I have a Snap-On digital battery load tester with a very heavy duty variable load cell which can be used for accurate evaluation of a battery, but it's also about $2500.00 worth of professional-quality equipment. Checking specific gravity and cold cranking amps after a 15-second load test is the only effective way of evaluating a battery's capabilities, but very few shops and virtually no retail battery vendors even know how to do that type of testing.
Jerry

Hotrod Lincoln.....Wow....you have some great equipment! My load tester is just one of those cheap types....the element inside gets cherry red-hot, and I think it is a constant 100 amp load.

I guess that under a load, it shows that the Volts drop, which is a sign of a bad cell. So, it is showing my battery in the Weak zone, and next I will pop open the cell covers and see how the acid levels are, and do the spec. grav. test.

Thanks for the info.

If you have to top off the cells, it's OK to use use clean tap water unless your local municipal water system has an extreme amount of dissolved minerals. Slow-charge the battery overnight before checking specific gravity or you might get a false reading from the water you just added not mixing with the acid thoroughly. Full-charge specific gravity should be somewhere around 1.265-1.300 on all cells, with no more than a .015-.020 variation between cells. A totally discharged cell will have a S.G. of 1.100 or less.

Electrolyte that gets below the level of the plates for an extended period of time will allow the exposed plate material to develop "sulfation", an extremely hard deposit of Lead Sulfate that is very difficult to dissolve by recharging the battery. I have had some degree of success reclaiming a sulfated battery by repeatedly discharging and slowly recharging it, maybe 10-15 times. Use an old sealed beam headlight to completely discharge the battery, then recharge at a 10-15 amp rate. Repeat as necessary. Good luck!
Jerry

Hotrod L./Jerry. thanks for the tips.....I will try that if the levels are low. I do have distilled water, which I will use if they are down. Some people claim that they can add a few teaspoons of magnesium and that can bring a battery back to life (maybe it helps reduce the sulfates?).

However, if the levels are low, I will need to correct the overcharging issue and the potential boiling of the electrolyte. Maybe corrosion (resistance) at terminals between the alternator and voltage regulator makes the regulator "think" the battery is weaker than it is, and then sends too many amps/volts to the battery. Had this problem on a motorcycle I had. Will do some poking around and follow up this week.

Thanks.

Lead sulfate is a normal byproduct of a lead/acid battery discharging, but as long as it stays submerged it re-dissolves back into the electrolyte easily during recharging. When it dries out it forms a very stable crystalline form that is hard to dissolve. A battery that stays in a discharged state for a long period of time can sulfate, even if the electrolyte level is not low.

A sulfated battery can cause a voltage regulator to go to its highest setting almost immediately after startup because the internal resistance of the battery indicates it's fully charged. Unless you have an adjustable set of points in your regulator, simply installing a good battery might solve your over-voltage problem.
Jerry

Hotrod...Jerry.....Boy, you are definately an expert when it comes to batteries/electrical issues....amazing. I do hope it is just a battery failure issue, and not something else....will let you know.

Hey....another quick question since you are so knowledgeable in these matters: I have an old 20s vehicle that I have been restoring, and it has a 6 volt battery. I do have a larger battery charger with the 6 volt option, but I was wondering if I could also hook up one of those small 12 volt trickle chargers without doing harm to the battery. Your opinion? Or, is there a simple diode/voltage reducer thing I can hook inline to make it work?

Hotrod Jerry......Well, I took the battery out so I could open the vent caps, and the electrolyte was low. Looks like two bars running accross the top, and then the thin plates below them. The fluid was below the two bars and barely covering the thin vertical plates. I poured about half quart of distilled water in to get to the right level, and now have it on a trickle charge as you suggested. Will do the test tomorrow.

I measured the volts before removing the battery, and it was back at 12.5. After the load test yesterday, it had fallen to 12.3, and somehow came back to 12.5 by today.

I also removed the old Voltage Regulator and opened her up. Inside, I used some thin emory paper to clean the two sets of points, and cleaned the plug connectors.

Update:

Had to put the testing on hold for a couple weeks.....issues, then the blizzard.

Could not locate my specific gravity battery tester, so after topping off the battery and charging, I put the battery back in and took her for a test drive. She cranked great when cold, and I drove on the highway for 10 minutes. Came back and raised the hood while the truck was idling, and put a voltmeter on the battery terminals.....it read 14.6 volts. I then reved the engine up to about 2000 rpms, and the battery showed 15.25 volts. I turned the engine off, and immediately tried to start, and it started fine. I turned it off, and waited 5 minutes and tried starting.....this time, just that slow sluggish sound of a starter that did not want to turn over. I checked the battery, and it was reading only 12.25 after failing to start.

My conclusion is a bad battery. Will replace it, and then test the charging rate at idle and at 2000 rpms......Im hoping it will be down to a normal range so as to not boil my new battery. If its still charging high, I will replace the voltage regulator.

Thanks for everyone's input.

OK- - - -couple of comments- - - -no, the 12V trickle charger won't work well as a battery maintainer for the 6V. You could find a heavy duty wire-wound potentiometer like a really big radio volume control and use it as a voltage dropping resistor to bring the voltage down to 7 volts or so for a battery maintainer for the 6V. Drop me a PM or an email and I'll draw out a circuit you can use for that. You'd need a 0-200 ohm potentiometer with about a 500 watt rating for the circuit I have in mind.

Even with the sulfated battery that would result from low electrolyte level, the 15+ volt reading is a little high from the regulator. There's really no need to replace the regulator- - - -just try adjusting the one you've got first. The set of points behind the Field wire is the voltage control. You need to very slightly decrease the spring tension on those points by either bending a tab or turning a screw. A very small adjustment makes a BIG change, so proceed carefully. Adjust the voltage to 14.5-14.7 volts with the engine at a fast idle (1500 RPM) against a new, fully charged battery. Be aware that the setting will lower slightly when the regulator cover is installed because the cover is a better conductor of magnetism than air, so adjust it .1 to .2 volts higher than the final reading you're looking for.

The final check on voltage is the electrolyte level in the battery. If you're needing to add water frequently, the voltage adjustment is a bit too high. Good luck!
Jerry

Jerry,

Just thinking here......would a house A/C dimmer switch work, and just hook up between the trickle charger and the 6 volt battery? Like you said, set it to where its putting out about 7 volts. I have seen the 6 volt trickle chargers for around $25, and thats probably cheaper than trying to buy the parts you are speaking of to make one (although the home-made one would probably be alot better quality).

Regulator on 69 C10: I will take it apart again and look, but I am thinking that there were no adjusting screws, so I would have to slightly bend the tabs. There are 2 sets of points inside the regulator.....you are indicating that I need to adjust the "field wire" points.....is this the one which has the alternator wire running to it? So, my goal is to reduce the tension a small amount so the points will close a bit easier. Let me know if this is right, and I will give it a try. 14.5 - 14.7 volts sounds alot better than the 15.25 its putting out now.

Thanks.
dwight

OK, my mistake- - - -I thought you were dealing with a generator system that has 3 sets of contacts inside the regulator. You've got the early-style external-regulated alternator. That regulator has a set of field relay points that will be open with the engine off, and a set of spring-closed voltage regulator points. The spring-closed points are the ones that need adjusting. Don't mess with the field relay- - - -it's either good or bad, and won't need adjusting. Slightly reduce the spring tension on the VR points, run the engine at fast idle,, and look for 14.5-14.7 Volts at the battery posts with a multimeter. If you want to check the alternator output, turn on all the accessories you can, like high beam headlights, wipers, heater fan on high speed, cigar lighter, etc., and check the battery voltage at fast idle under full load. Anything above 12.5-13 is OK with a big load applied.

I looked up some potentiometers on Ebay- - - -one heavy duty enough to adjust battery charger output is going to cost somewhere in the $30.00-$50.00 range, so a dedicated 6V trickle charger will be a better choice. Keep a close watch on the water level of the battery when it's on a trickle charger- - -you don't want to let it get low. No, a household light dimmer probably wouldn't work well for that application.
Jerry

Jerry,

Yep, this is the early style alt. with the external regulator mounted behind the front grill.

Adjusting the regulator.....so, it sounds like its better to take the cover off, but leave it mounted behind the grill/headlights so that I can adjust it while testing it. Im hoping it might have an adjusting screw for the tension, but I cant remember.

More info.: I took the caps off the battery and used some metal wires attached to my voltmeter to check the volts from cell to cell. Making sure the metal lead does not go too deep and touch the metal rod in the electrolite (which gives a false higher reading), I got about the same reading of 2.0 volts on each one. I even got 2.0 with one lead on the positive battery terminal and the other lead in the last cell beside it. However, on the negative battery terminal, I got a real low reading with a lead on the cell beside it, and the other lead on the neg. post. Is this negative post reading normal, or a sign that this is the bad cell? Also, after charging the battery to a good 13 volts (on a 10 amp charge for a half hour), the battery slowly goes down to the 12.35 range.

Will continue kicking this one around until the problem is solved.....Im kinda betting that a new battery will be the answer, and this will also reduce the charging volts from the regulator.

A normal lead/acid cell that's fully charged will have a voltage of 2.1, for a total 6-cell voltage of 12.5-12.6 but using the electrolyte as a test medium isn't a very good method. With a sealed-top battery that's about the only option, but it isn't very effective. It's beginning to sound like the battery is a good part of your problem, but that oddball charging voltage reading needs to be corrected. Here's another quick load test- - - -disable the ignition so the engine won't start, and crank the starter for 15 seconds with a voltmeter attached to the battery posts. After 15 seconds, with the engine still cranking, a good battery will be above 9.5 volts. Don't run the starter much longer than 15 seconds or it can overheat and damage itself- - - -definitely not more than 30 seconds.
Jerry

Jerry.....Ok....will do the cranking test with voltmeter on battery. Then I will go out and get a new battery if it falls below 9 - 9.5 volts.

Update......Jerry, I did the cranking test for 30 seconds, and had the voltmeter resting on the windshield so I could read it. It dropped down to 9.35 volts at the lowest during the cranking.....so, it seems to still have some life in it.

I took off the old starter and made an attempt at putting the new one on......it absolutely drove me crazy since the 3 bolts did not want to quite line up. I scrambled from underneath the truck with the new starter and did a thorough comparison with the old starter using a micrometer. The 3 bolt holes matched, and they even machined the middle one a bit more so it could pivot some (and I guess stand a better shot at fitting). So, it seemed that it should fit. However, no go after several frustrating attempts. Finally I examined the two starters and the new one has more cast iron for the solenoid connection area, and it was made 1/4" closer to the starter nose. That little bit of a change caused it to rub on the engine block, and would not allow the bolts to go in. What a pizzer! So, now I have to try to find a manufacturer that makes the old style to fit my 69 Chevy 307.

Any suggestions if Advance Auto cannot find a better fit?

Try swapping the nose cone of the old starter onto the new one- - - -just be sure the bushing that supports the front of the armature shaft is still good. That small bushing has a habit of wearing out and allowing the armature to contact the field coil pole shoes, resulting in a "dragging" starter that doesn't come up to full speed. It's not terribly difficult to swap nose cones, but the solenoid will have to be removed during the procedure. Disconnect the terminal that goes into the starter housing, remove the two screws holding the solenoid to the nose cone, and twist the solenoid 1/4 turn to disengage the front tab. There's a pretty stout spring in there, so don't let it catch you by surprise!
Jerry

Jerry.....I took the ill-fitting starter back to A.Auto, and they pulled down another with the same part number. This one was an exact match to the old one, so I exchanged it. That was a huge relief......took it home and it fit into place perfectly.

Engine started right up, but I still have not had time to run her up the road to get the engine warm, and then try starting. I am hoping this does the trick.

Thanks for all your help and suggestions.

Be sure to deal with the over-voltage situation by either adjusting or replacing the regulator. One other suggestion might be to retro-fit the vehicle with a later-model internally-regulated alternator. The 10-SI alternator that was an OEM item from the late 1970's forward is a simple swap, and eliminates the external regulator.
Jerry

Jerry.....and anyone with some ideas:

Well, I put the new starter in, and she started right up, no problem. Today I did the real test of driving her, getting her warm, and turning off the engine, and then trying to start.

Took the truck to the landfill with a load of trash, and I was so confident that my problems were over that I backed in, and turned the engine off. Unloaded the trash cans, and hoped in the seat to start, and I got was a "errrrr........errr........er". Barely turned over. Sounded as if the battery was almost dead. A lady gave me a jumpstart, and even with her big truck running, the starter was having a hard time turning over......but finally she started up.

Drove her home with no issue.....the engine sounds and seems to run fine, although there is a bit of hesitation (time to clean the points, adjust the dwell). When I got home, I left the engine idling while I checked the battery voltage. Once again, she was over-charging......at idle she was reading 14.8 volts and when I increased the RPMs to around 2000, she read 15.5 volts. When I shut off the engine, the battery read 13.7. 10 minutes later the battery was at 12.8.

So, I know that the voltage regulator is adjusted too high....I need to try to tweek that down.

So, the old starter was working fine......the new starter has the exact same symptons......starts fine with a cold engine, but does not want to start with a warm engine. (Note: Engine oil pressure is great....starts off high, but as the oil warms up the pressure goes to the normal area (gauge a bit past the middle notch). The water temp runs cool, barely getting up into the normal range. I was also watching the volt meter, and at times it would jerk to the right, showing above-average charging going on, and I was not running any electrical items.

Is it possible that the solenoid and starter does not like having 15 volts of juice flowing into it?

Also, I did a load test on the battery last week, and it showed it was getting into the weak range, but not in the "bad" range. I also did the cranking test for 30 seconds, and the volts dropped to 9.35, which is still good.

So, any ideas as to what could be going on? Is there something internal that could be heating up and then causing the engine to turn hard?

H E L P..........

Just a thought.... how about you turn it by hand when it is cold, then get it hot and turn it by hand again... just make sure the ignition is OFF!!

Rusty Rod.......Thats a good idea, but the trouble is that I have tried turning with the alternator belt in the past, and I could never get the engine to turn that way. Not sure if there is room to get a big socket in front of the lower crank pully.

I guess I could also do a roll test cold and hot.......see if there is a major change in the resistance when I pop the clutch in 2nd gear when cold vs hot.

Has proper sized battery cables been discussed?

justhorseyaround.......Yep, someone asked about that, and I have great battery cables, heavy duty. But why great starting when cold, and a no-go when warm?

Everyone......a mechanic friend emailed and said it could be the waterpump bearings about to seize up.....they get hot when the truck is running, and when I turn off the engine, they create alot of resistance. Pump was making a bit of noise a few years ago, but I never put a new one on. Not making noise now, but I guess it still could be going bad.

Comments on the pump idea?

Im gonna get the truck warm, then loosen the belt to the pump, and see if it starts. If so, then its definately the pump.

I never would have guessed water pump.

On a scale of 1 to 10, water pump problems would be about a 23! It's more likely you've got bearing troubles or pistons getting tight enough to give the engine a lot of drag when it's hot. How does it start after about a 15-minute cool down?

There's nothing I can think of about the starter that would have a problem with high charging system voltage. Unless someone has drilled and tapped the crankshaft for a center bolt, you won't find one on a stovebolt six- - - -the balancer is a press fit. Some of the balancers have a 3/4" square hole that a ratchet or a 1/2"-3/4" square drive adapter will fit.
Jerry