Are Lucas electricals as bad as everyone says?


A few weeks ago, I reached the point in the resurrection of my 40-year-dead Lotus Europa Twin-Cam Special where the drivetrain was finally back in the car, and the intake, exhaust, and coolant systems were buttoned up. The time had come to drop a battery in, twist the key, pray to The Automotive Powers That Be, and check for oil pressure.

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2019/05/13/lucas-electricals-as-bad-as-everyone-says

I love it - great article. I own a Triump GT6 chock full of Lucas’ finest and am currently working thru to try to get the beast running. I’m an optimist so keep plugging away. The plus side? Lucas electricals may be a mess but they WERE simple…so generally not too hard to fix even for a novice like me.

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A third offered that many, if not most, of the bad rap of Lucas electricals doesn’t come from the electrical components themselves, but from the ham-fisted attempts at jury-rigging around the problems—for example, wires hastily cut, spliced, twisted together, and wrapped with electrical tape, which is a recipe for poor electrical connections.

Can confirm: my '74 Spitfire has what can only be described as … “interesting” wiring additions to it. I’m the third owner, my Dad was the second, so I can only presume that the alternations were done by the original owner. For example: at some point, the turn signal stalk switch failed. Rather than sourcing a replacement, the DPO drilled a new hole in the wood dashboard, bought a DPDT toggle switch, and wired the turn signals through the new switch with speaker wire. I’m not sure how that repair was any easier or cheaper than the $21 it cost me to source a replacement stalk from Victoria British, but to each their own.

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“A third offered that many, if not most, of the bad rap of Lucas electricals doesn’t come from the electrical components themselves, but from the ham-fisted attempts at jury-rigging around the problems—for example, wires hastily cut, spliced, twisted together, and wrapped with electrical tape, which is a recipe for poor electrical connections.”

This is the money quote that alerts me to simply walk away from the completely delusional. If Lucas stuff didn’t fail, there would be no cobbled repairs. “American mechanics are the reason SU carburetors have a bad reputation!” Nobody ever touched a carburetor that hadn’t acted up or ceased acting like its twin on its own. “Lever-arm dampers are just fine,” which is why there are tube-shock conversion kits. “The Jaguar XK is one of the best engines of all time,” which is why there were two major companies sustained by replacing them with stove-bolt V8s. English cars are great for people who prefer wrenching to driving.


Anybody that complains about Lucas has obviously never had any dealings with Magnetti Marelli electrics. The simple Lucas systems on my toys are reliable if they have not been messed with by previous “auto electrical specialists”. If in doubt when buying an LBC, make sure that you remove any previous electrical “improvements” and confirm that the system is installed in accordance with the applicable wiring diagram and reliability should result. My small fleet gives me acceptable performance considering the average age is 40+. One of my pals has just traded in his 4 year old benz SUV because of an on-going rash of electrical gremlins emptying his pocket.

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I had a 63 TR3, it was 5 years old when I got it, never had an issue with the wiring, but maybe because it didn’t have that many miles on it, I think it was in the mid 60,000 range. It always
started and was ready to go, never had to do that much wrenching on it.

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I drove a 75 Spitfire for 13 years starting when the Spitfire was already 10 years old and the only electrical fix needed in 13 years were new brushes in the starter.

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I’ve driven a 67 MGB since 1979 and got over 200000 out of the starter. Keep your grounds clean repair what joe the Chevy mechanic buggered up and enjoy your British car!


I’ve owned many British cars. 99% of the time if something electrical doesn’t work it’s usually a bad ground.

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What a great way to start the day, many good yuks. Looking forward to next weeks addition. PS when you master the Brit stuff graduate to the big time tackle a mid 60’s or 70’s Fiat and earn your PHD. Jim


There is a reason why they drink warm beer in England…it`s because they have Lucas refrigerators!!!


I happen to be the Technical Coordinator for the North American MGB Register, which serves all post MGA MGs, including the MGB, MGC, the post Abingdon cars, and the 1100 and 1300 sedans and of course the Midgets.

The British wiring codes are amazingly simple and easy to learn. Brown is power, black is ground. After it is switched in the ignition switch, Brown becomes white. When White is fused, it becomes the green wires, and when Brown is fused, it becomes the purple circuits. When Brown goes through the headlamp circuits it comes out as Red with Green stripes for parking lights, which do go through the fuse block and come out red to go to the lamps, and red with a white stripe to go to the dash lights., and bown comes out of the head lamp switch as blue for head lamp dip switch. blue with white stripes are main beam, and blue with red strips are dipped beams. Any wire that has a black stripe is a typically a switched circuit ground (like a lot of negative side two wire horn systems) and green wires tend to feed the convenience things on the car. The yellow wires are for the alternator or generator. There are more, but armed with this info you can troubleshoot almost any system on a British car.

Grounds are the big problem, keep them clean and assemble them with silicone dielectric grease. the little bullet connectors throughout the car need to be likewise cleaned and assembled with dielectric grease, and check to make sure the heat hasn’t overcome the springback of the metal for the secure connections. Some of the weaker contacts in the switching can greatly benefit from having a simple 12 volt relay placed in the circuit to take the electrical load and heat off the switches. Although early British cars typically have two fuses for the entire car, and the later ones have four (up to the early eighties) the electrical systems if properly cared for and kept in good order are almost bullet proof.

Dave Braun


Magneti Marelli - the company that gave Lucas a good name!


As a DeLorean owner I can vouch for the, um, “unique qualities” of Lucas electrics. The good news is that the problems are well documented and (relatively) easy to fix.

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Correct as far as it goes. Motor cycles are really where Lucas earned their reputation.


My poor Bultaco Metralla suffered from Lucas electrics: yes, they were as bad as you might have heard.

Curse you, Zener Diode!! Who needs lights?

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When I got my 67 MGB the hardest electrical job was undoing all the fixes the PO had done to the car. The Lucus wiring usually had bullet ends that connect to sleeves that can cause problems. The bullets are brass and the inside of the sleeves are steel, the resulting dissimilar metals can corrode. I just cleaned up the bullet ends and replaced the sleeves, (they are real cheap) renewed the grounds and put every together with dielectric grease. I also put relays on the headlight circuit since the old switch was failing. Been 17 years now and no electrical problems.


Interesting article that covers what many of us have to tackle when dealing with a classic car regardless of the heritage.

Too many times even with the new models, we have all witnessed the results of a person with little to or no experience & the best of intentions tries to add wiring & making a dog’s breakfast if not equipped with the right tools, parts or researching on how to complete addition of electrical accessories so it is something to be admired in the future by the next owner.
In most cases of butchery I think it’s from wanting to complete the job and nothing further. Out of sight, out of mind.

There are a lot of upgrades we can perform to make our older systems more reliable if we can’t replace the entire harness one needed avenue is to having cleaned connectors and a good electrical connection grease/sealer.

It’s always a good rule of thumb to take into consideration that an old car will need to have the wiring harnesses replaced or gone through to make it as safe & reliable as possible.

Safe driving everyone!


Never understood the benefit of having a positive ground on Lucas electrics.

Never understood driving on the left hand side of the road.

Never understood the need for Whitworth bolts.


I worked as a mechanic for many years, starting in the early 70’s. I worked on a lot of European cars of the 60’s and 70’s. I can’t tell you that any one was noticeably better or worse than the others. I sometimes thought that Robert Bosch was fighting Joseph Lucas for the title of prince of darkness. And Magnetti Marelli wasn’t any better. Throughout my career I found that the vehicles condemned as unreliable were almost always the ones that the typical American car mechanic didn’t understand. I’ve certainly had to repair Lucas systems, but I’ve repaired at least as many Bosch, Magnetti Marelli, Ford, Delco etc systems. They all fail. Understanding the system and repairing it properly are the key to reliability.

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