• Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

External ballast resistors - do they go bad?

tdskip

Yoda
Country flag
Offline
Hi guys - do external ballast resistors like in the picture below go bad? Should they be tested from time to time? How best to test (multimeter presumably) and what am I looking for?

Hot-Spark%20Ballast%20Resistor.jpg
?
 

70herald

Luke Skywalker
Country flag
Offline
Anything can go bad. To test it you need to check its resistance with your multi meter. I should be about 1-2 ohms.
Do you have any reason to suspect it is not good? Unless it has been overheated it is really unlikely that it would go bad, and they can withstand allot of heat.
 

dklawson

Yoda
Offline
While the ballast resistor can go bad... you would know in an instant if it did.

After the engine starts, all the coil power flows through the ballast resistor. The failure mode for a ballast resistor would be to "burn open". If that happens, the resistive element burns in half and no more electricity would flow. In short... no power would reach the coil and your engine would stop.

As above, normal resistance would be between 1 to 2 Ohms.
 

71MKIV

Jedi Warrior
Offline
As you crank the engine would be trying to run until you let go of the key, then it would quit.

Shorting the two wires together would get you home if you are not more than 20 minutes from home.
 

Mychael

Senior Member
Offline
Well if they came from a broken home, poor upbringing, but don't despair with love and education you can turn them around. :square:
 

SkinnedKnuckles

Jedi Trainee
Offline
Mychael said:
Well if they came from a broken home, poor upbringing, but don't despair with love and education you can turn them around. :square:

Ha!
 

Banjo

Yoda
Country flag
Offline
Ask anyone who owned a 70s-80s Dodge truck. they mounted them to the firewall where the rainwater would run down over them when you opened the hood. *poof* done. Most owners of those trucks had an extra in the glovebox, and a piece of inner tube screwed on the firewall just over the resistor.
that was the exact symptom. Would try to start, then die as soon as you let off the key.
 

Bob Claffie

Jedi Knight
Country flag
Offline
Just to clarify the situation, they don't "taper off". Either they work or they don't so testing is rather pointless. Bob
 
Similar threads
Thread starter Title Forum Replies Date
E MGB external alternator regulator MG 2
T external sealant for oil leaks Spridgets 6
Zimmycobra For Sale Misc. External Engine Parts - 1966 TR4A Triumph Classifieds 1
andrea Problem with the throttle linkages due hing external temperature Austin Healey 34
T TR4/4A TR4A wiring - gear reduction & external solenoid? Triumph 6
T External Mirrors - advice requested Austin Healey 10
T External Trim Restoration Restoration & Tools 1
Hap Waldrop Ray's external oil system Spridgets 3
Bob McElwee Bugeye Hardtop External Latches Spridgets 2
TR674 External oil line Triumph 23
eschneider external rocker oil feed line Triumph 13
A Internal hinge converted to external? British Motor Corp 4
Jim_Stevens TR2/3/3A Ballast resistor to prevent hyperflashing Triumph 5
Lotus Club SoCal Ballast Point Long Beach Social Lotus 2
Marla TR4/4A Ballast or Non... Triumph 6
2wrench TR6 1974 TR6: Ballast vs Non-ballast system. A look at the wiring. Triumph 58
NutmegCT ballast resistor Other Cars 10
A Ballast resistor Triumph 7
SilentUnicorn MGB ballast wire mgb 77 MG 2
TulsaFred Ballast resistor Spridgets 28
regularman Ballast resistor mystery Spridgets 2
A ballast resistor 75 mgb FORUM Navigation Questions 0
A MGB ballast resistor 75 mgb MG 2
H Ballast resistor MG 9
RynoBoy74tr6 Ballast resistor location.... Triumph 10
newmexTR3 TR2/3/3A Pertronix on TR3 Ballast Resistor or no? Triumph 3
8 BALLAST RESISTOR???? Triumph 12
john_j Coils and ballast resistors Rover / Land Rover 2
T Wedge Cut wire on TR8 Ballast Resister Triumph 2
J Spitfire Spitfire Ballast Resistor Triumph 3
C Ballast Resistor Spridgets 34
B TR6 TR6 / Pertronix / Ballast Resistor / etc Triumph 13
RichC Primary Ballast Resistor Ignition? MG 1
R Link to Ballast resistor wireing Jaguar 0

Similar threads

Top