Hi to alls
What would you recommend to me to replace the original Lucas C42 DC generator by an alternator ?
My Jaguar MK2 is equipped with power steering

Regards
Gérard

There are a couple of alternatives on the market that are a direct replacement for the generator and look exactly the same but have an alternator internals. They come with the pick up on the back for the power steering pump and can be positive or negative earth but I don't know why you would fit an alternator without converting to Negative earth. They all push out a lot of power 40 to 45 amps. Not sure if you require so much power in a 1960s Jaguar as we are not running all the modern electrics of today.

The first is the https://www.powerlite-units.com/sear...23&_a=category Not cheap at £636.

Then there is the Powerlite. https://www.autosparks.co.uk/powerli...isted-steering Very expensive at £800.

The third option is https://www.multisparkignition.co.uk.../dynamator.htm Again a direct replacement and has all the features of the Dynalite and Powerlite but at a cheaper cost of £189. The Dynamator pushes out 45amps. This is the one I fitted to my car 5 years a go and not had a problem with it.

The most economical way to update to alternator is to fit an ordinary Lucas 12 volt alternator from post-'67 British cars, vans and trucks. We used to do this al the time on older cars in the '70s and '80s. I know Lucas parts are no longer available new but I got a replica Lucas alternator for about .£40 off e-bay for my Ford tractor about four years ago and it has been fine. There are plenty of old Lucas alternators around but parts for these are getting very scarce. I'm pretty sure any period 12 volt alternator, such as Bosch or Japanese, would also fit with the minimum of fuss.

For an alternator, you have to convert to Negative Earth and this means the original Jaguar clock cannot be used as these are Positive Earth only. Also the radio is likely to be Positive Earth but may have a switch underneath to convert to Negative. Otherwise that will also have to be replaced with a later Negative Earth model. Everything else will work fine on positive or negative earth with no problems.

Ray.

Were there Lucas alternators that had power steering pumps on the back? I've not seen an original Lucas that could do that.

not Lucas but Rock Browning in Texas used to sell an alternator described as coming from a diesel truck that had the proper hookup for the MK-2 and S type power steering.
I don't know what happened to Rock or his inventory. He just disappeared.
He was the guy who designed and developed an a/c system for our cars.

I thought the original post needed an alternator to just replace the original Lucas dynamo, and had a separate belt drive for the power steering pump. I must have misunderstood.

Ray

I have converted numbers of early Jags from positive earth to negative earth. I am not aware of any problems with the original clocks having a polarity change (apart from them generally needing cleaning and lubricating to get them going)

My '66 S Type had been updated with a Lucas alternator by the previous owner and everything worked fine apart from the clock and the positive-earth Radiomobile radio. These both seem totally kaput, as well as the self-parking on the wipers.

I did the usual research by Mr Google, asking around, classic car forums etc, after removing the non-working bits to check on the bench. I discovered this is appears to be a common problem but I could do nothing with them. I found a company that will update these clocks with new inner works but it's quite expensive.so I've fitted a neat 2 inch Neg Earth spare 12 volt clock over the parcel shelf. I'll still probably get a proper modified clock for the rev counter when I've managed to justify the cost to myself and have picked up another spare non-working clock to repair.

The wiper wiring wasn't easily rectified for some reason or other so I've got the parking of the wipers off to a fine art now but it's still on the to-do list. A used Radio CD player from a local breaker for a tenner has sorted the wireless out.

How do you insulate the original clock from earth, Bill, to keep it Positive Earth? It would be great if I could just fix my old clock to keep its originality. The dash isn't quite the same with a Hesketh motorcycle clock underneath.

Ray

The polarity sensitive clocks were later ones with a diode to suppress arcing across the contacts. It might work if you take out the diode and carefully clean the contacts. The cheap repair, though it requires a bit of fiddling, is to replace everything behind the face and the hands with a quartz movement and a battery (or if you want to add USB to your old car, use that to power the quartz). The quality repair is to replace the contacts with transistor switching; it maintains some originality including the gentle tick for those with ears sensitive enough to detect it. I think that's what the Clocks4Clasics kit does.

PS. I imagine that with a Google search to design the circuit and some soldering it would be possible to transistorise a clock for minimal cost.

Thank you - I'll keep looking for a spare clock so I can play with it. I've got a spare rev counter, with no clock, so I can mess around without taking the car off the road.

Ray

in the US, www.jaguarclock.com modifies existing Jaguar clocks for $85.00 USD with a reversible mod in case you want to go back to a non-working clock. Positive or Negative ground.

Recently there was a post by Rishi where he stated he did some surgery on his clock with a kit from Clocks4classics. Changed the points to a PCB. https://www.jaguarforums.com/forum/m...3/#post2827861
Unfortunately there is not a big write up on it but details of Clocks4classics can be found here. https://clocks4classics.com/ There is nothing on the website to say they convert from Positive earth to Negative earth so it might require an enquiry with them either by phone or Email to confirm.

The Clocks4Classics kit is suitable for positive and negative ground. I think their early kits had to be connected the right way round; the more recent are dual polarity.

Thanks Pete.