You are here:

Classic/Antique Car Repair/1980 Rolls Royce Ignition


QUESTION: Good afternoon Vern,
Is their a way to check the distributor amplifier or ballest resistor on a 1980 RR Silver Shadow II?  In previous correspondence with me you had suggest that they may be my problem.  One additional thing that I have noticed is the coil seems to have a constant voltage on it and it doesn't discharge until the starter switch is turned off.  Thus firing once.  Any help?


ANSWER: Not That I am Aware of. What exactly is it doing?
I have had both the coil and the ballest resistor replaced.
A bad ballest resistor can produce several symptoms. The most
common is shutting of the engine while driving. However, a
bad coil could cause the car to run rough or hard to start or
not start at all. I guess even a bad coil could stop firing in
the middle of driving.

---------- FOLLOW-UP ----------

QUESTION: My 1980 RR Shadow II has no spark to the plugs. Took resistance readings on the existing coil. Side to side (primary winding?) was .7 ohms.  Side to middle = 4.95 K ohms.  Voltage to + coil terminal was 11.48 volts.  Voltage to negative coil terminal was .648 volts.  Thought coil was weak so replaced coil with NAPA ECH IC 277.  Still did not start.  Took resistance readings from center of distributer cap (coil wire side) to connection that rides on the distributer rotor.  No continuity so replaced the distributer cap.  Still did not start so replaced the distributer rotor.  Still does not start.  The voltage to the new coil positive terminal is 5.93 volts.  The voltage to the new coil negative terminal is 1.45 volts.  Don't know why the change in voltage. Any suggestions on what to do next would be greatly appreciated.  I had started the car and backed it out of the garage befor it died.  Started it again after some difficulty and drove it back in the garaage.  Have not been able to start it since--8-9 days.  

Hi Bill:
I notice you check the coil and replaced,
but what about the plugs themselves? If OK,
then the problem is mostly in the Amplifier
inside the distributor or the Ballast Resistor.

Inside the distributor there is a small circuit board
with a silver amplifier on it. This kit can be removed
and replaced.

The Ballast Resistor is a silver steel plated unit mounted
on the firewall that control current to the coil.

Either the Amplifier is bad...not enough current to the plugs, or
the Ballast Resistor is current to the plugs.

Hi Bill:
I think you have the wrong coil.
I believe coil NAPA Coil IC277SB 12V does NOT require an external resistor and
you car has a external Ballast Resistor. See my original post below...

Try using Coil ECH IC88 (but make sure it states: REQUIRES EXTERNAL RESISTOR)

Classic/Antique Car Repair

All Answers

Answers by Expert:

Ask Experts


Vern Bullock


I can answer most questions about autos built in the 1920 through 1990. Mechanical issues and technical questions are my expertise. I also have a general knowledge of most older automobiles. Keep in mind, I can only provide answers if the questions are very specific and complete. Without details, I can only speculate and that's not good for solving your problem.


I have owned and maintained Silver Shadows for over 10 years now. I find most mechanics and even Rolls Royce mechanics have very little knowledge about these automobiles. I have researched these cars in quite a bit of detail and can pretty much tell you what is wrong, if you can describe the behavior in detail. I have saved quite a few RR owners a lot of money and aggravation due to improper diagnosis. I am the owner of Classy Transportation, LLC a luxury limousine service specializing in antique cars, classic cars, vintage cars and exotic cars.

All around the Internet

I hold a BS degree in computer science and a MS degree in mechanical engineering.

Awards and Honors
I regularly compete at car shows and average around a dozen awards annually.

Past/Present Clients
See Web site at:

©2017 All rights reserved.