Upratedg Alternators

[Deleted]

RatSport have uprated Lucas alternators advertised in January's (!) Practical Classics. I have problems keeping the battery charged. The alternator is working but driving in the cold , wet and dark still runs the battery down (and it is fairly new) so I am tempted to change. Is it just a matter of buying one of these uprated jobs and replacing the old one with it or are there other electrical issues to be addressed / parts changed if I go for an 80 amp replacement alternator?
Thganks in advance for any help

[p5tgc]

The change to a higher output alternator is not too difficult, but as the original alternator had external control over the regulator and warning lamp a bit of minor re-organising of the wiring needs to be carried out. Jim Walker covered this in detail in a past issue of Take 5, (November 2000) using a Lucas LRA147, as used in many Ford Cortina / Capri /Transits. This is a 45 amp unit and I can vouch for the ease of fitment, improved output and reduced noise.

[Deleted]

Thanks that is very helpful. I have only been a club member for about a year or so so if anyone has can e mail or post me a copy of the Nov 2000 Take 5 article I would be very grateful.

[Smallfry]

Remember though, if you fit an 80 amp alternator...........which is no problem in itself.........that you must upgrade the feed cables to it.

[p5tgc]

Quaker,

Send a note of your email address to me at [e-mail] and I will email a scan of the article to you.

regards

[Deleted]

Thanks to both of you for your assistance, it is very much appreciated.
All the best.

[RichardF]

Quaker, I have also seen the Ratsport advert and have taken the plunge on the 80 amp alternator and the high torque starter motor - the latter being quite expensive. However, with my early retirement planned for next August, I am spending the money while I have it coming in so to speak. I am additionally fitting a new (and thicker) main battery cable from the boot to the engine compartment and also upgrading any associated wiring.
I hope for a "no hurdles" modification (yeah, right!) regarding the alternator as I changed my Riley Elf's dynamo for an alternator and did not require too much head scratching. However, the P5b is a bit more complicated with having a relay etc in circuit, so I will have to do some homework on this as I am unsure at present what it actually does and whether I can omit this or not.

Regards to all
Richard
Southampton

[Phil Nottingham]

Alternators with bulit in regulators dispense with the relay and warning light can so its just a matter of bridging out the the warning light can and disconnecting the field isolating cables. Its best to arrange all ignition fed supplies except the coil via a realy anyway as it protects the terminals of the switch particularly if its the thief proof set up as these will be charred anyway. The actual wiring for the alternator is dead straight forward

The main problem will be upgrading the already heavy wiring to/from the alternator/starter solenoid/the big main junction strip under the dash. An extra cable from the solenoid and a completely new alternator feed would be the best option. the existing cables will be inadequate on their own.

The ammeter is a shunt affair but could be overloaded I suppose in extreme circumstances or far better put another resistance in either parallel or series with the existing resister and recalibrate the meter. The main battery cable is well worth upgrading given its length and age.

Study the wiring diagram well - have it enlarged to A3 its much easier to follow and its not that complicated in the end

Hope your retirement plans work out and good luck

[RichardF]

Phil,

Many thanks for the advice - all taken on board. I have also ordered heavier cable to replace the other wiring I will disturb and want to replace with heavier gauge. As I am at work and it's really quiet, I have already enlarged the relevent part of the circuit diagram and, as you say, it's much easier to read.

Regards and thanks again
Richard
Southampton

[RichardF]

A quick update.
The new 80 amp from Ratsport alternator arrived and fits perfectly onto the V8 without modification - except, the pulley is slightly smaller in diameter. My original pulley is 3.1" dia., the new one is 2.52" dia. With a bit of math, this works out approximately 1:1.26 in ratio, meaning the new alternator will rev more for any given engine rev. More math means at 3000rpm, the old pully gave 5490rpm, while the new smaller pulley gives 6960rpm. A call to Ratsport tells me that I cannot over-rev the alternator; even if this were marginal, I rarely do over 60mph anyway (I enjoy the P5 ride).
I did request a larger pulley from him but he cannot help me as he gets the whole units from Montreal in Canada. Notwithstanding this, I thought I could just swap the old/new pulleys, but no! The new alternator's spindle is much bigger than the old one and anyway, I can't for the life of me get the nut undone. So, I have a choice to return the alternator and stay as is or, keep it and live with it. One other thing though. Because the new pulley is slightly smaller, I have come to the end of the adjustment for belt tension. However, 2 minutes of filing an few mm gave the extra tension (old belt). I haven't wired it up yet but will update when I do.
Richard
Southampton

[RichardF]

Latest update.
I have fitted the new 80 amp alternator and wired it up and all works okay. Good positive charge showing with all loads on. There was no need to fiddle with the alternator adjuster arm as there is plenty of adjustment left on it; I suspect the V belt on the spare engine I initially tried it on is the wrong one fitted (too big).
Richard
Southampton

[Deleted]

I all can some one send my an email from the nov 2000 take 5
On changing to a lucus alternator from a ford
Thanks
Vince [e-mail]

[RichardF]

Vince,

I have a copy and can scan it at work tomorrow. I will then send you it via e-mail.
Regards
Richard
Southampton

[Deleted]

Hi thank you very much

[RichardF]

Vince,

I have e-mailed you with the modification information.

Regards
Richard
Southampton

[Deleted]

HI all i have just been given a lucus LRA 101 34A
Will that be ok to use or do i need a higher one
Thanks

[RichardF]

Latest on my alternator upgrade: It had been working absolutely fine. Then one day I started the engine up and the ammeter went to full + defllection (80 amps). This naturally perturbed me somewhat. I changed the ammeter and the symptom remained. I also noted that with the ignition on and headlights on (engine not running), there was no discharge showing on the ammeter at all; regardless of the load. My suspicion was lack of regulation of the alternator output.
I have since sent it back to RATSPORT who have subsequently sent it to somewhere in Norwich for test/repair. Fitting the old alternator back in brought all back to normal. Thank heavens I did not remove any of the original items.
Will keep you updated.
Richard
Southampton

[Welsh Warlock]

Could someone please e-mail me a copy of Jim Walker's article from Nov 2000 as I can't find that issue. i think I loaned it to someone who was doing the conversion!

[e-mail]

Many thanks

[p5tgc]

Scans emailed to your account as requested.

[Welsh Warlock]

Thanks Trevor.