Alternator Conversion - Does your car talk to you?

Post by: **Galwaylotus** » Sun Jul 03, 2011 2:20 pm

Well, my hand has been forced. Yesterday I checked to see why my battery was going flat and found only 10+ volts at the battery with the engine running. The controller was installed upside down so I had to remove it to get at the adjustment screws. When I did, I found the mounting tabs on the resistor in the base had rusted away so there was no contact. I've been threatening to convert to an alternator and the car is telling me it's now time!! :roll:

Just unfortunate that it will be off the road for a few weeks whicle I organise the parts and convert the tach to negative earth.

I'll post progress reports.

Post by: **billwill** » Sun Jul 03, 2011 3:43 pm

>and convert the tach to negative earth

And the battery connections ! Don't forget them !!

>and convert the tach to negative earth

All I had to do to mine was open it up and swap-over the positive & negative wires inside.

Post by: **RichC** » Sun Jul 03, 2011 6:30 pm

anotherone bites the dust!
I hope all goes to plan for you.
there's an ever diminishing number of us +ve earthers out there.... bit like flat earthers ....

Post by: **Galwaylotus** » Sun Jul 03, 2011 7:30 pm

billwill wrote:>and convert the tach to negative earth

And the battery connections ! Don't forget them !!

>and convert the tach to negative earth

All I had to do to mine was open it up and swap-over the positive & negative wires inside.

No battery in the car right now. I took it out to put it on charge. Today I took the opportunity to remove the tach and to trace the cables from the fuse panel in preparation for replacing it with a 8-fuse blade type panel. It takes me a while to start a job that isn't always straight forward but when I do start I dive right in!! :lol:

Post by: **billwill** » Sun Jul 03, 2011 11:33 pm

You still have to do something about the battery cables !

The former + and - clamps may be different sizes and/or may not be long enough to reach the battery terminals unless (perhaps) you rotate the battery 180 degrees.

Post by: **ceejay** » Mon Jul 04, 2011 12:10 am

When I rebuilt my S2 back in the eighties, the first thing my auto electrician
did was to convince me to get rid of the Lucas electrics - inc generator,
and associated regulator buzz box, etc.
He built a complete new wiring loom to suit the new alternator, the switches
operate various components through relays. There are plenty of earth terminals,
there has not been any major electrical issues since.
It does not hurt to bring the electrics up to more modern standards.

Post by: **ericbushby** » Mon Jul 04, 2011 5:22 pm

I have recently changed my tach to neg earth. There is a green wire on the supply tag and a 150 ohm resistor on the earth contact near the tag. Change those two connections.
Also change over the connections to the white wire which passes twice through the input transformer on the back of the tach so that the signal current still goes the same way. It took me several hours of soaking with WD40 etc to open the unit without any damage.
Then 10 minutes to do the job, followed by derusting and painting.
Eric in Burnley
1967 S3 se type 45 (not running yet--next week!!!)

Post by: **Galwaylotus** » Tue Jul 05, 2011 5:32 pm

billwill wrote:You still have to do something about the battery cables !

The former + and - clamps may be different sizes and/or may not be long enough to reach the battery terminals unless (perhaps) you rotate the battery 180 degrees.

Not to worry. The PO left the earth cable long so I can use the cables as they are. Thoughtful of him. Just wish he'd built it as a negative earth in the first place! :roll:

I got the bad news today. I rang Speedy Cables and there's no problem converting and refurbishing the tach. It's just that the lead time is four weeks!! I want to do our club's summer run on the 23rd

. I guess I'll just have to bridge around the tach and reinstall it when it's converted.
My plans to go for a Denso alternator have taken a knock as well. I can get a 45A Lucas ACR for less than half the price and it won't require changing the mounts so, in the interest of time and money, it looks as though Joe Prince of Darkness wins again!

Post by: **Galwaylotus** » Sun Jul 10, 2011 7:45 pm

Update time: I only got a short window this weekend to work on the car but at least I got the dynamo off. While I was digging around in the engine bay, I thought I could see the whole crank pulley above the frame cross-member. I may try to remove it without releasing the engine mounts. I'm still limited to when I can get dry weather and pull the radiator. I hope to get the alternator this week. I have decided to leave the water pump driven by the rear groove (same setup as original) and to drive the alternator off the front crank pulley. I'll have to have a spacer made for the fan and either move the alternator forward or have a step-out pulley made for the alternator. Stay tuned!! :roll:

Post by: **alexblack13** » Sun Jul 10, 2011 9:04 pm

Hi,

This is just my humble opinion and do feel free to completely disregard,but why do you see the need to drive the new Alternator via a separate drive belt? Yes it is quite important not to over tighten the belt to help preserve the pump bearing, but the Alternator will happily drive very well with a quite slack belt with no issues what so ever. Keeping a good eye on the belt condition and the spare in the boot will make sure you have no problems at all.

You are fixing something which ain't broken at all.. Or am I missing something?

My Alternator equipped Sprint runs the belt quite slack in fact and has never muttered a 'cheep' yet. The car's electrical system is quite a light loaded affair, and separate Alternator belt drive systems are (I think) quite un required.

Keep us posted as you go...

Alex...

Post by: **Galwaylotus** » Sun Jul 10, 2011 9:15 pm

Alex, I never disregard feedback from those that have been there and done that! As it happens, I may need to delay the new pulley and if so I can get some experience with the alternator in a "standard" setup. If you think I can get away with the one-belt system running no more tension than with a dynamo, it would certainly be an easier conversion!

Thanks for the input.

Post by: **alexblack13** » Sun Jul 10, 2011 9:35 pm

You will have no problems. Don't over tighten the belt though.. Leave about an inch of slack.

Even at night with headlamps and lights etc never had any drive problems at all. Try it 1st and if you find you have the need..Report back...

:wink:

Alex....

Post by: **elansprint71** » Sun Jul 10, 2011 11:39 pm

Agree completely with Alex.

Post by: **UAB807F** » Mon Jul 11, 2011 5:26 am

Another one for "same here". I was amazed just how slack the belt could be and still work, and that's with a very old 17ACR.

Post by: **Galwaylotus** » Mon Jul 11, 2011 9:16 pm

Ok. I picked up my new alternator this evening and did a quick trial fit. It looks as though I'm going to need a longer fan belt. The distance between a line running through the centre of the mounting and adjustment screw holes and the centre of the shaft is different on the alternator (Lucas ACR 17+) compared to the dynamo. I think it will fit ok but I'll need a slightly longer belt. I'm also going to see if I can get a spacer for the rearmounting flange to the mounting bracket. I'll get some heavier cable for the connectinn between alternator and battery too as the rated current goes up from 22A to 45A. :roll:

Alternator Conversion - Does your car talk to you?

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