Volvo AQ130 Ballast Resistor Help

[elv_1986]

Does anyone know if a Volvo AQ130 (OHV) should have a ballast resistor in the +ve wire to the coil when running?

I'm just fine tuning my rewire, the Seloc manual says one wire to the coil, with a ballast but nothing about a second feeding 12v to the coil for starting?

Thanks

 

[JKay]

Does anyone know if a Volvo AQ130 (OHV) should have a ballast resistor in the +ve wire to the coil when running?

I'm just fine tuning my rewire, the Seloc manual says one wire to the coil, with a ballast but nothing about a second feeding 12v to the coil for starting?

Thanks

There is a wiring diagram in the manual,you can get yours on the link below

http://www.volvopenta.com/VOLVOPENT..._ENGINES/Pages/out_of_production_engines.aspx

 

[elv_1986]

Thanks for the link. It is showing the same as my wiring diagram, a wire from the ignition switch to the coil with a resistor. I just cant understand the reason for this resistor?

 

[Swordfish]

Thanks for the link. It is showing the same as my wiring diagram, a wire from the ignition switch to the coil with a resistor. I just cant understand the reason for this resistor?

Hi, The resistor may work in the same way as those used on the Volvo V8 engines, the coil uses 12v to start, then 6v to run engine.

Paul

 

[elv_1986]

but there is only one feed to the coil, through the resistor?

 

[superheat6k]

Why have a ballast resistor

The coil for the ignition will work with a 6vdc supply, so the ballast resistor is to split the battery voltage at 12 - 14 vdc in half so the coil sees the 6v it wants to work properly.

However, and the reason the engine maker opts for a 6vdc coil rather than a 12v, is that when the engine starters operate the massive surge from the batteries to the starter motors causes the system voltage to plummet. If the coils were rated for 12 v the spark would disappear as soon as the starter operated and the engine would struggle or possibly never start.

Instead during the starter operation the battery voltage is bypassed around the ballast resistor, so although the system voltage has dropped considerably, there is still penty to satisfy the ignition coil and provide a nice fat spark at the plug.

Thats it !

 

[Swordfish]

but there is only one feed to the coil, through the resistor?

Hi, I'm not sure how the wiring goes on the 130, in this photo, ballast resistor is held to coil with yellow cable tie, can you see the two purple wires on the left, and single on the right. It may be that the reduction in voltage is only used on the GM V8.

 

[JKay]

I think your on the right track as a mate "converted" my 131's to run the system you describe,so as standard may have run 12v coils to start ?

 

[elv_1986]

So it looks like I need to alter the way this works from the way Volvo originally wired it.
I need a 6v coil, and need to add a 12v supply to the coil when it is turning over.

Would it matter if the coil gets power from both wires when it is trying to start? As it stands now my +ve is live when the key is in the run and start position.

 

[superheat6k]

12 v supply to coil

No, this will not be a problem.

The simplest way to do this is to take a feed from the starter side of the solenoid heavy output cable direct to the coil (same position as the ballast resistor connection +ve), thus when the solenoid energises to operate the starter the 12 v feed is sent direct to the coil.

The permanent feed via the ballast resistor is simply bypassed, as the electricity will take the path of least resistance, but only whilst the starter is operating.

To work correctly the resistance of the ballast resistor should match the operating impedance of the coil, which will vary from its non operating resistance. If two resistors of equal value are placed in series across a voltage the voltage drop across each will be equal.

The simply check that the coil is properly powered is to meausre the voltage across it alone with the ballast resistor connected. A 6V coil should put up with 8V without harm, but would not sustain a higher voltage for a prolonged period.

 

[andy59]

Dont want to nit pick but if you take the 12v feed to the coil for starting from the load side of the starting solonoid , when the engine is running you would end up with 6v at starter motor , i think it should come from the +12v from the starting circuit ( ignition switch ) so that when the key is not turned +6v from coil is connected to nothing .

 

[superheat6k]

12v supply

You are quite correct on this - apologies, so yes the 12v supply from the ignition switch to the solenoid would be preferable.

 

[markcw]

D0 what i did and remove the ballast resistor and buy a 12 coil, but i did have to upgrade to pertronix 12 v spark module, job done, no stupid resistor anymore no points, old technology out the door.

Boat starts so much better now on the dime a quick flick of the key and she running was not like with the 6v system.

 

[spannerman]

Just checked the Volvo workshop manual and there is no 12v feed from the starter or ignition switch for starting, just a feed via the ballast to the coil.

 

[elv_1986]

I think adding another 12v feed off the starter may be the way to go after hearing all your comments.

Spannerman, my manual says the same as that, but it confused me why there is only one wire with the ballast.

 

[spannerman]

If you are going to do it then either check you have a separate output on the cranking position at the ign switch from the terminal feeding the starter, or connect it to the starter solenoid wire at the starter via a relay or it will backfeed and energise the starter continually. Don't ask me how I know!. (fitted a Toyota ballast coil to my Mini Cooper back in the 80's and found out the hard way I needed a relay to isolate the coil from the starter after the engine had started).

 

[VicS]

FWIW
When these, and similar, engines were fitted in Volvo cars built for operation in cold conditions they had ( from 1976 onwards) such a ballast resistor in series with the ignition coil.

During cranking the full 12 volts was applied to the coil from an additional terminal (16) on the starter motor solenoid.

During normal running the reduced voltage reaches the coil via the ballast resistor.

No relay... just the extra connection on the solenoid presumably connected to an extra contact in the solenoid

 

[coolbreeze48]

Does anyone know if a Volvo AQ130 (OHV) should have a ballast resistor in the +ve wire to the coil when running?

I'm just fine tuning my rewire, the Seloc manual says one wire to the coil, with a ballast but nothing about a second feeding 12v to the coil for starting?

Thanks

I know this is an old thread, but just in case anyone else may have an issue with this problem, here is my 2 cents worth. I have an AQ130, 130hp, twin carbs. The coil which is on my ignition system is a resistor coil, being the ballast resister is built into the coil. The wiring diagram does show a ballast resistor, and if your coil is not a resistor coil you will need the ballast resistor, if it is, you will not. If the coil ohms out to 3 ohms or right at that, it is probably a resistor coil, check ohms from positive to negative terminals. If you need to add a ballast resistor to your ignition system, be certain that it is wired in such a way that it does not keep the starter solenoid hot in the run position or else your starter will stay engaged. Think relay.