Logo
FULL SITE MENU

ballast resistor failure

B

briang0

Regular Contributor
Went down to the boat tonight to go out. bb chevy point ignition Started her up to warm up after about 5 minutes she sputtered and died I had replaced the resistor while trouble shooting a different problem about 2 years ago, it only had about 30 hrs on it.. I check and the ballast resistor had failed. I replaced it with my spare the one I removed 2 years ago and off we went. About 1.5 hours later I'm returning to the dock and she dies about 50 feet off the float would not restart. Luckily the wind and the current were with us and we floated into the dock. I checked and the ballast resistor had failed again. I had an old resistor and I installed it and she started right up. Any ideas on what could be causing this. The only thing I did this year was install a new starter and of course a tune up. I'm wondering if I swapped the r and s wires on the solinoid when I installed the starter if it would start at all or be causing this. I'm going to go buy a couple more resistors just in case but if they only last 1.5 hrs I'm not going to be going far. She has been running real good since she went in Memorial Day. Any Ideas?
 
Time to toss that setup out and go with a high performance, 12 volt, "no external resistor required" coil. Seriously. What you got there is Model T technology. About 50 bucks at Jegs or Summit will buy you a nice, modern coil that will make you and your boat much happier.

Jeff

PS: If you agree with me, call their tech guys, tell them exactly what you have, and they'll tell you what to buy. And tell them you'd prefer to avoid any more of those stinkin' ballast resistors (since them might recommend one).
 
Resistor failure can be caused by excessive voltage output...whatever you decide to do, you should check the charging system output first
 
You didn't switch the R & S leads as you know when the key was turned to RUN.

Agree with bobbyc to check the alternator output voltage.

Not all ballast resistors are created equal....a bad batch is not unheard of.

If you take jeff's advise, also consider a breakerless conversion kit to eliminate the points. If you are going to update the ignition system, might as well eliminate the high maintenance portions.
 
Ok I took Jeffs advice and called Summit. The tech said no problem you just need to find a 1.4 ohm or higher internal resistance coil. I check and have found a 1.5 ohm coil. It just sounds too easy am I missing something. Will I have to change the points or condenser what about the point gap? It is currently set at .020. Is more better should I go to 3 ohms. Confused
 
briang0 said:
Ok I took Jeffs advice and called Summit. The tech said no problem you just need to find a 1.4 ohm or higher internal resistance coil. I check and have found a 1.5 ohm coil. It just sounds too easy am I missing something. Will I have to change the points or condenser what about the point gap? It is currently set at .020. Is more better should I go to 3 ohms. Confused
Click to expand...

If you have to start the boat in -20 deg, you might wish for the ext ballast resistor. But for real world boat starting, yes, pitch the resistor, fit an "internal resistor" coil, and you are good to go. Once you get that undercontrol, you might chase down an electronic equiv of those points/condensor. Better long term reliability and spark advance stability also. THese engines run hard, burn a lot of fuel, do it a favor!
 
Don't know what went on during the discussion with Summit but I'd be a bit leary of using a coil with a primary resistance of 1.5 ohm without a resistor. More like 3 ohms sounds reasonable for a coil with an internal resistor. The idea is to limit the current flowing thru the primary side so things don't burn up. You can try it but I'd have a resistor and an extra set of point on the boat.

The point gap shouldn't change unless you use some exotic coil. The gap is a proxy for the dwell angle the points run at which sets the energy stored in the primary circuit.
 
I was down at the boat tonight and took some measurements this is what I found. With the current ballast resistor I measured both sides while running. I have 12 volts on both sides. I traced the wires back from the resistor and one side comes from the solinoid the other comes from what appears to be the switch. The side from the starter goes to the coil. This setup makes no sense from any wiring diagram I have looked at. I replaced the ballast resistor and coil about 2 years ago troubleshooting a no start situation. I took the old coil to a Napa store and they handed me a new coil that had written on it use external resistor and a new ballast resistor. I'm wondering now if the old coil had a internal resistor and the previous owner never removed the old ballast resistor. It looks like now I'm going to remove the resistor and replace the coil with a internal resistor coil. Is it correct for me to keep the wire from the key switch and remove the wire from the r termial on the solinoid?
 
Last edited:
That wire, from the solenoid to the coil, is how that setup sends a full 12 volts to the coil during cranking ONLY. Let off the key, the solenoid drops out, and the ballast resistor circuit takes over to deliver about 9 volts.

If you're getting 12 volts on BOTH sides of that resistor in RUN, there's something wrong there! One side should be 12, the other around 9 volts.

Jeff

PS: One of my boat mates (a sharp electronics guy) converted his Chrysler electronic system to eliminate the stock ballast resistor and 9 volt coil. He bought a massive, 45,000 volt 12 volt coil and wired it direct (using a 0.8 to 1.5 ohm resistor in line to eliminate voltage spikes). The spade terminals, the solenoid circuit, and etc. are gone, replaced with bolt on connections. Motors run better than ever before!
 
Is it possible that the solenoid is sticking?? Keeping the resistor line high? The starter was not brand new it was my spare. I ordered a 3 ohm 12v coil last night. When that is installed and running will I see 12v in and 9 out to the points? I did check the output of the alternator and I have 14.5 volts at the battery.
 
If you have 12 V on both sides of the resistor, either the resistor is shorted (no voltage drop across it due to no resistance) or the coil's primary winding is open (no current flowing thru it, which means no spark).

If the solenoid was sticking, the starter would be engaged.

If you switch to the internal resistor coil, you'll only see 12VDC on the + terminal; the nominal +9VDC point will be inside the coil's case and not measureable. The voltage at the - terminal will be either +12VDC or zero, depending upon the points being open or closed. Also, if you switch coils, you can tape off the lead from the solenoid's R terminal, if desired.

PS - resistors can't eliminate voltage spikes, or even dampen them, without a reactive component.
 
briang0 said:
I have 12 volts on both sides.
Click to expand...

If there is 12V to ground on both sides, then there is no power dissipated by the resistor. Does it feel cold? You have been burning out resistors, and this statement is not consistent with that fact. These resistors normally run hot, hot enough to burn you.
 
The resistor was warm but not hot I could easily touch it. I'm hoping to go down again tonight and check the voltages again. The new coil will not be here until next week. I was hoping to use the boat this weekend. I might just go buy a couple ballast resistors just in case.
 
..."..resistors can't eliminate voltage spikes, or even dampen them, without a reactive component. "

Interesting. I know they keep the coil from burning out if one accidentally leaves the ignition on overnight. Without a resistor the coil dies in an hour or so.

Jeff
 
For a simple resistive network: Power = voltage*voltage / resistance.
so, if you left 12 volts across a 1.5 ohm coil (points closed), you have 144/1.5 = 96 watts dissapated by the coil. It will get as hot as a 100 wat light bulb, pretty hot. The coil gets damaged.

If, on the other hand you have a ballast resistor ahead of the coil, it's more like 8 volts across the coil, 8*8/1.5 = closer to a 40 watt light bulb. The coil stays healthy.
 
So does that mean I should keep a ballast resistor even though I get a coil with an internal 3 ohm resistor? I'm easily confused
 
Yes, of course, the conclusion!

Here are my conclusions:

If you are running old style points, condensor, and need to start this beast below -10 degrees, use an external resistor coil, wired correctly to shunt the ballast during cranking.
For the 99.9% of us who don't need to start in extreme conditions like that, but want a reliable ignition system, the first thing to do is buy a "internal resistor" coil, and throw away the ballast resistor and probably one extra wire.
The next step is to replace the points/condensor with a reluctor type pickup system.
Any future steps would aim at increasing the spark energy, with EST, or some cool marine rated aftermarket kit (MSD, jacobs, etc). This will allow enough spark during plug fouling (worn engine), high rpm (racing mode), lean burning (let's hope not), and other difficult conditions (low voltage cranking).
 
UPDATE:
I installed a 12v 3 ohm coil tonight. Coiled up the wire coming from the r post on the starter and taped it up where it would not get wet. Motor starts and runs fine. I will take it for a shake down cruise tomorrow. I am wondering what should I keep my eye on to make sure the new system is work well. I felt the coil after letting the engine idle for about 10 minutes and it was cool to the touch. Felt the wires going to and from the coil and they were cool also. I plan on checking the points tomorrow night after a couple hour cruise. Recommendations?
 
Took her out tonight for about 1 1/2 hrs. Started up great ran out at about 1500 rpms for about 10 minutes went up to 2500 for about 30 minutes everthing was good stopped to check the coil temp it was warm but I can keep my hand on it no problem. Brought the rpms up to 3000 no problem ran her like that for about 15 minutes. When I brought her up to WOT she sputter and stumbled so I came back down to 3000 after a minute or so I tried again and the stumble was gone but I could only get about 3200 rpms out of the engine. I was never able to get to 4000 usually 3500. I'm on a river that has a super strong current so if I'm heading into it I would get 33 - 3400 with the current 3500 tops. I'm a little concerned with the stumble but since it went away I'm not to concerned. One issue I do have is when I got back to the dock as I slowed down to come in I couldn't get the RPMs down to the idle which is 650. I never had this issue before not sure if it has anything to do with the changes I was going to adjust the cable. I have never timed the engine I can't find the timing marks on the flywheel and it's impossible to do it from the front of the engine. So I'm a little closer but still not where I want to be. How would I know if I was overheating the points. Thanks

Brian
 
For proper WOT operation, just about everything on that engine needs to be solid. For instance, you need to time the engine to about 28 degrees at 3000 rpm or so. If the spark plugs and dist. cap are over 2 years old, replace them. This could account for the lower than expected rpm at WOT. Are the props clean? For the stumble that comes and goes, this could be dirty fuel or some crud in the carb. HOw old is the gas?

Explain the lack of access to the front of the engine. How do you get to the belts, the RW pump, etc? You cannot even see the timing mark indicator at the balancer?
 
You need to find a way to accurately time that motor! If not, you could be looking at burnt pistons--especially since your motor seems to be lugging badly: WOT only gives 3,500 rpms on a good day? Something is wrong here.


Jeff
 
Due to the over hang of the deck I only see the harmonic balancer from the sides. I do have enough romm to get my arms and tools in to change belts. I have the bruses to attest for that. I did have someone tell me once to cut the cabin steps out and put them on hings to be able to access the front of the engine but not sure that would be a good think for the structure of the boat. The engine is a crusader built 1964 BB Chevy 409 that is shoe horned in there not by me. I'm hoping to save my pennies and then sell that engine and put in a much newer 350. I know very well what the marks look like on the front but what does the timing mark on the flywheel look like? I have spent a lot of time looking for it but never have been able to find it. I'm planning on bringing my timing light and dwell meter down this afternoon. Although the dwell is not adjustable just figured I'd check. I'll try again to look in the front but I'm a little leary sticking my face in there with all the moving parts. I replace the points, plugs, Condensor, rotor, and distributor cap every year and the gas and fuel separator are less than 1 week old. Keep you updated. Thanks for all the support.

B
 
Last edited:
briang0 said:
Although the dwell is not adjustable just figured I'd check.
Click to expand...

THe dwell is adjustable, although there may not be an external distributor access. If dwell is too low, this will cause high speed miss, since the coil is not allow enough time to build up its magnetic field. Also, timing changes will dwell (point spacing) adjustment. Set the final timing after the dwell is set. I don't have specific dwell specs for that engine, but 30 degrees +/- 2 should work for you.
Many engines have a bellhousing cutout at the top to measure idle timing. You may see a small pointer in this area, this will line up to a dot or some feature on the flywheel at about 10 deg BTDC. This might have to be the way to time your engine. Visual the movement of the flywheel feature as you increase rpm beyond idle. #1 cylinder wire and a simple timing light should work for this.
 
Thanks dd I have always worked on engines that had an external dwell adjustment. I am planning on heading down to the boat tomorrow night after work. My fathers day present today was replacing the power steering pump in my son's car. Well at least I got to spend some quality time with him. `I have the owners manual on the engine so I have all the specs.
 
I was able to check the timing tonight. I had to bend into a unnatural position but I could see the markings. I had to clean the metal plate but once I did that I was able to see the marks and it is exactly 10 degrees BTDC. I was not able to check the dwell because both my meters were broken. I guess not using them for 30 years helped. Went out for a ride even though I didn't adjust anything ran for about 1.5 between 2000 and 3000 RPMs and everything was great. I even got her over 3500 rpms as soon as I went to wot she started to sputter and I got a strong smell of gas. I'm starting to thing I have a problem with the secondaries in the carb. I have an Edlebrock 1409. I have never adjusted it or really touched it except to clean it. Is there and adjustment for the secondaries? I'm going to replace the wires I was thinking on the way home that they are at least 4 years old so I will replace them this week. Not sure were to look next.
 
Sounds like progress.

You aren't gonna like this but I think you'll find the consensus is you need to check your timing advance as well as at idle. If the advance mechanism isn't working properly, you'll never get to WOT and your cruise economy will usually suffer as well.

I'd suggest making sure the ignition is "by the book" correct before starting with the carb adjustments (yes, there are several). If you don't have one, get the manual from Edelbrock's www site.
 
Yes, you NEED to check the dwell. Its very easy to set the points too far apart, get too little dwell, and ruin high speed performance. I would not dive into the carb just yet.
 
I am planning on getting a new meter and a advance timing light over the next few days. I believe I set the timing light to ~38 degrees or what ever number it is suppose to advance at 3000 rpm bring the rpms up to 3000 and when I point it at the timing mark it should read 0 or will it read 10 because I'm starting at ten? If both look ok I"m going to replace the plug wires and then move on from there. Thanks for the help.
 
Back
Top