R.I.P Lucas starter (V12)i

Hello everyone,

Returning from a 100 miles trip, the starter simply died , luckily in front of the garage .

I had bought a high torque Starter 10 years ago from SNG, which I never installed as I thought it impossible to reach the top bolt fixing the starter to the belll house in an automatic. Luckily at the UK Jag site I found a photo showing very clearly a hole in the transmission bulkhead allowing to reach that bolt from the inside, so I manage to renove it without major difficulties , after removing exhaust, canister , lower mud shield etc . This is not documented anywhere in the workshop manual . :roll_eyes:

The starter looks impecable, but there is clearly a short circuit somewhere . Problem , the starter I had from SNG is for early models , with 29 mm pinion, 11 teeth my car from 1974 has the 25 mm pinion with 9 theeth so I need to buy a new one .

Question-1 : Which starter would you recommend , I have reserved the Lucas one in SNG, any views ?

Question 2 Any advantage in rebuilding the old starter instead ? It’s more difficult to put that one in , but I wonder if the original pre engaged one has any advantages . After 50 year and 120k miles the pinion seems new … but the new ones are much smaller and lighter, drain less current and turn the engine faster.

Many thanks


Reaching the top bolt from.the interior :

The ‘wrong’ starter I had in stock, for engine NR up to 1S7000, 29 mm 11 tooth :


If properly rebuilt it should last another 50 years. That’s what I did with mine.
I also prefer the sound of the original one.


It might be a trick of the light but a couple of the copper armature coils look as if they’ve come into contact with something - just as they come out of the commutator? May have been just in the dismantling? In any case nothing appears burnt. At your present point of progress I would be stripping the solenoid and looking for burning at the contacts there. My XJ6 is still running its original unserviced Lucas starter - now plus 150,000 miles. I did, however, refurbish the solenoid.

Yes. You know it’ll fit and work ! :slight_smile:

The modern starters are popular and most people are happy with them, but…

Years and years ago I put modern high-torque starters on both Jags I owned at the time. There were a few glitches. Eventually it all worked out but, personally, I feel like the juice wasn’t worth the squeeze. Since then I’ve stayed with original starters and, when needed, had them rebuilt locally.

Just my two-cents


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A stock starter is pretty robust.
Your commutator looks great and even the brushes look good. As stated, check the solenoid.
You need a shop with a growler to check the armature.

Mini starters are like anything else. There are good ones, and there is cheap junk.

Doug has it correct. You know it fits, it’s lasted this long and was designed for that motor! If it were me I’d take the old starter to a long-established repair shop,have it thoroughly overhauled back to original specs then reinstall it. When it fails in another 50 years you can address your options at that time… :thinking:

My 2-cents too!

Happy Trails,


I have to agree with everyone here: the stock starter, in good nick, works just fine.

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I’m with Doug probably rebuild for $100 and it will out last you ,sell the other one
Lite wt starters are all the rage on aircraft for obvious reasons but what they don’t tell you is if the engine kicks back the starter often breaks
They are not robust enough to take the power of the kick

Thank you all.

Piece of missing information, the sympthom was a click click click with no movement ,Indicating the solenoid was ok but as soon as the starter engine connected the battery voltage went down to almost zero , desctivated the solenoid and the process restarted .

Then with the starter out I bypassed the solenoid and connected directly to the starter engine , big spark and barely no movement - meaning shirt circuit somewhere.

I am with you regarding fitting again the original after repair, but there are a few things such a rubber isolator which is now brittle and I’m sure cannot be found easily. Then Belgium is difficult for this type of repairs, not like in the UK or US. Anyway, first I will see what caused the problem .

But on the other side , I heard no positive opinion on less current drawn and more torque , meaning quicker startup ? Also reffing the old one again is heavy and a very tight fit , and only one hand fits to handle the 11kg beast … Ok this can be sorted out I think .

Starters in an automatic are critical , I don’t want to be stranded In the middle of nowhere …


No need for higher revs, if the engine is healthy and properly tuned it should fire up right away.

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I can’t see any advantage to using an old style starter if a new light weight geared starter works. I don’t care if it turns the engine over faster. I do like less weight and less current draw.

The old stuff, properly maintained, worked. No argument there but the new stuff really can be an improvement. I’ve got an electronic fuel pump, LED lights, and 123 ignition for the same reasons. They’re all an improvement over the old stuff and they’re all things that can be without modifying the car.


It is kind of like comparing apples to oranges, and I never did get the chance to install it in my Jaguar, because the original 53 year old Lucas starter worked fine, but the Gustafsson starter that I got for it is exactly the same one that they spec for 2 liter Rovers. And it transformed the Rover!

The NADA-spec Rovers (10:1 comp. ratio) had a known issue of throwing out the Bendix constantly, especially when cold. It was a very frustrating situation, sometimes leading to 10 or 15 tries to get the engine started. I believe it had to do with the power pulses, or in this case compression pulses, of a four-cylinder engine versus the much smoother cranking of the six cylinder Jaguar engine.

The car cranks much livelier now, and never kicks the starter out. Some people on here have indeed reported good results with the Gustafsson starter, and I would not have hesitated to put it in my E type.

This will probably drone on and on in one of those useless back-and-forth about “how all the good stuff was just fine back in the day and who needs this newfangled new stuff!” discussions, but I tend to agree with your main pointsg.

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It sounds like you are asking for troubleshooting advice?
You have it off and apart. Either take it to someone who has the test equipment and have it rebuilt, or check and see what you can find, repairing and issues yourself.
Based on the very limited information you have provided, I would not be surprised if one of the end bushings/bearings is worn out and the armature is touching the fields, preventing it from turning and thus pulling high amps. But that is just a thought.
Yes, there could be a short, but I would suspect you will see the burn spots.

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So this is how it all looks disassembled .

All looks fine , except rubber dust cover solénoïde, brittle . I cleaned everything, measure for any grounding and no defaults found .

I put all back but same problem . Meaning possibly internal short of the filed coils, who knows . I will take the field coils and armature to test if I find someone around with a ‘growler’ as suggesred by @Big2Bird

Question Does anyone have the specifications of the resistance of the filed coils ?

Bottom line, evem.if it all looks impeccable, we are talking about insulation material for 50 years n an oven . For an automatic a Starter is a critical component and rebuild has to be done with quality for reliability. A full rebuild is too much work and would need to be done properly, meaning someone who has also the rubber protection parts (eg, on the solénoïde etc) …In addition as the whole thing is out it would be a good policy to change the solenoid . In practical terms this all means sending it to the UK (I’m in Belgium) where those parts still exist in a few specialised workshops, at a cost, not forgetting custom taxes now.

Way-ahead On the other hand new starter, two days delivery time , 300 euro (270 USD), reliability (hopefully) and much less current drain and easier installation (@montauk1989 )

But of course , I will keep the original one. @Doug_Dwyer @Wiggles @Dick_Wells - were I in the UK and I would possibly follow your advice . @Jagjim1 - 100 IUSD would be only for shipping costs …

I think this is the wiser thing to do …

I will report back when car will be ready , I will not work on it before mid Nov.

A-word-of-caution will you disassemble a Starter take care with the position of the fork actuated by the solenoid . It looks simetrical but it’s not and I did not take note of the original position. When fitted in the wrong direction it will work but the gap at the end of the pinion end-course cannot be adjusted to the right specs .

Many thanks to all


PS @Marco , the car starfed very well also with the old starter


If it’s still apart I would check the armature coil resistance - ohm meter to each opposing segment on the comm. They should of course measure same. Check for shorts between armature windings with ohm meter to adjacent comm segments. Field coils will also measure similarly to one another. Also check these to ground. Finally check the solenoid terminals to ground for shorts. The brushes still look pretty good to me - there is a spec for length to changeout. Specs for the various resistances should be in the factory service manual - my cars are older but the books have them listed.
If it’s back together test the terminals to ground - might find a short if it’s there (whilst rotating).
As some of us have noted there is no sign of burning.

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Hi Rui,

If you are in Belgium I understand, if it’s anything like Germany, finding a suitable repair shop to overhaul the starter may be easier said than done. Generally Germans don’t repair, they replace! That said, first thing to ask a rebuild shop is if they have a “Growler” machine to test the armature. An Ohm meter isn’t sufficient!
That’s a later version starter and that’s good for parts availability. Most likely the armature will be good, just needing a dressing of the commutator and segments and a visit to the Growler to verify function. I would also request new brushes and springs - 50 year old springs need replacing! Replacement coils are available but take special equipment to replace them.
While your initial check may indicate all is well I would put my trust into a shop that specializes in repairing/overhauling such equipment. While it’s out I’d replace the starter solenoid as a good-faith precaution. For 50 years it’s served it purpose well. Now it’s time to let a specialist restore it for another 50 year adventure.
When the start sequence is initiated the Starter relay sends voltage to the solenoid causing it to engage. If battery voltage is low the resulting start sequence may work but arcing damage may be done to the solenoid contacts. The only way to tell is to take the solenoid apart. If I have the starter out replacing the solenoid is a minor cost!
Clearly shown is the arcing that has happened. Sometimes, depending on battery voltage, the contacts fuse making the solenoid stay engaged!
My recommendation - take the starter to a reputable repair facility and have it overhauled. In another 50 years you may have to revisit this!! Money well spent IMHO.

Happy Trails,


I put a gear reduction starter on my series 3 23 years / 100k+ ago. The car fires instantly. For a while a couple of years ago I had some vapor lock issues which took some cranking to overcome. The starter could crank and crank.

An ohm meter or test light is perfectly satisfactory to do the first round of diagnostics. Either will find an open circuit on the armature or a short between the armature coils, if the insulation resistance is poor or short circuited. If the tests suggest a “fail” then a potential “root cause” diagnosis - at the fist level - can be made. If they are inconclusive then take it to a specialist.
As I read it Rui is in two minds as to whether or not he should persist with a repair or swap out for a gear reduction unit. If the test lamp or ohm meter test fails and a simple repair cannot be identified, then, I think he has his answer and he will save the money he might otherwise spend on a specialist to purchase a new unit. My money is still on the solenoid at this point, from the little we understand.

There’s all kinds of YouTube’s on how to do this stuff these days ,spend sometime researching
Or pack it up nicely and convince the wife that she needs a holiday to a location that has a starter alternator repair shop there a dime a dozen in Canada although not as plentiful as they use to be
These shops often work more on industrial equipment now like fork lifts etc .
Get it to me and I’ll take it to a shop for you
Maybe someone is travelling :luggage: ?
Hard to believe you can’t get it done at home shipping will kill it just don’t get rid of it

Jim, Rui lives in a very restrictive, controlled society, I would image rules much like Germany. Living in Stuttgart for 8 1/2 years German Federal laws were so much more restrictive than what I was used to in the States. They didn’t have auto parts box stores so if you needed a part the dealer was usually the only source. When you took your vehicle to a dealer for, say a CVS joint boot replacement, if the dealer found ANYTHING not meeting TUV specs they were required to fix it. Tail light bulb out! It was replaced. Wiper blades worn. They were replaced. Broken windshield - replaced!!! Having unrestricted speed limits on parts of the AutoBahn, the German Federal system didn’t trust rebuilt or overhauled parts. Factory new was the standard!
If the starter solenoid is the problem then a quick dressing of the armature contacts may restore it, along with a new solenoid, for a few more years.
I’d put it all back together, install a new solenoid and retest. Fingers crossed - he may get lucky!

Happy Trails,