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MG MGB Technical - Fiesta Alternator Upgrade

Well, the old 17ACR died on my sister's '70 BGT, so I've replaced it with a Ford Fiesta unit (55Amps), which should be enough to cope with her high powered stereo (no other major accessories or loads).

I upgraded to an 85 Amp Bosch unit in my '70 GT, but it required a little more fiddling and engineering to mount, whereas the Fiesta really is a straight bolt on. Sadly the much ballyhooed Saturn unit is not available ANYWHERE in the world but the US (and shipping makes it too expensive). Having said that, I'm very, very happy with my Bosch unit (BXF1255A), and can also recommened it to anyone.

Thanks to Bob M for his well-read tips on the Fiesta upgrade. My experience:

1) Straight bolt on. Just had to move the internal tap piece in the back alternator lug a little

2) Had to trim a little off the original lower mounting bracket, as the slightly larger fan of the Fiesta unit just caught it.

3) The Fiesta unit is a nudge 'fatter' - so needs to be lifted/rotated clear of the engine mounting point. This requires a slightly longer fan belt - an extra ~30cms over the stock 900mm.

4) The wiring was very straight forward: the old lugs slipped out of the original plastic sleeves and clipped right on. Also added an extra 10ga brown up from the starter solenoid, just to ensure maximum output availability.
Curtis Walker

Thanks for the kind words, I am glad I DID NOT remove that site when I was thinking about doing so some months ago. And thank you for your feedback! Feedback like yours is how others get the benefits of your experience and I learn something new that may help finesse the site into something better and more informative. Cheers!
Bob Muenchausen

No, thankYOU Bob!

Just an small update - I actually needed a 940mm fan belt to allow the alternator to clear the engine mounting point and I suspect this will be what is generally required for those looking at this upgrade. 940mm is also the absolute maximum the OE lower bracket can stretch to - a fine line indeed, but successful :)
Curtis Walker

Curtis,
I was once caught out installing the Bosch unit without access to a longer fan belt. I figured out after test-running it that the alternator body was rubbing against the engine mount, and when I removed the alternator I found a nice divet in the soft aluminum! Not having a longer fan belt on hand, I gritted my teeth and used a die grinder to carve a bigger notch out and ta-da - no more rubbing. (not a recommended method!)

Adam
Adam Birnbaum

Can someone give me Bob M. address, am interested in Fiesta Alt. switch
Gary G

Hi all.

Just out of curiosity..

It is very tempting to think that a higher output alternator will be beneficial somehow, but is this really the case ?. How many times have you heard of a car stopping because the battery had gone flat in a car with the charging system and battery in good condition and the engine running ?.

My personal experience with a Land-Rover having a 30A alternator, an ammeter and a voltmeter suggested that the 30A unit was quite adequate.
The ammeter never indicated a discharge of more than few amps.

The only circumstances that I can think of where a bigger alternator would help would be being stuck for a long time in traffic in the dark with the HRW and heater on, but a little common sense (eg switch to sidelights, reduce the fan speed) would resolve this.

A high-power stereo doesn't actually consume a huge continuous current, unless you have it operating at silly volume.

I always switch off all electrical loads and run the engine at a brisk tickover for about 30 seconds before stopping the engine (unless it is only a brief stop), as my experience with the Land-Rover' instruments taught me that this tops-up the battery for the next start.

Converting from a dynamo is a different matter, of course, as is running an off-roader with a winch, etc, or a modern car with electric everything.

BTW, I thoroughly approve of fitting teted or re-built parts from the breakers, so a Fiesta alternator does have merit.

Comments anyone..? Don
Don

Gary

Here is Bob's web site that includes information on fitting altrnative alternators. http://www.s95408591.onlinehome.us/index2.html

Regards,

Barry
B.J. Quartermaine

Hi Don,

My B/GT has had a Fiesta (Bosch) alternator, as
well as an ammeter, for several years going.

Once the engine is purring, the ammeter needle
never goes into the negative (-) irregardless of
what electricals are switched on...unlike it did
with the stock Lucas 16ACR.

With the Fiesta alt, I've driven with wipers, heater
blower, high beams, overdrive, and radio - all
running simultaneously and smartly (no dragging
or sluggish movements, no dim lights) - without
seeing the ammeter twitch a single bit. With the
Lucas 16ACR you have to budget your amps and
prioritize which electricals to have active, or off.

For those without an ammeter - the first thing you'll
notice is that all of the lights will shine noticably
brighter...including the dash panel guage lights.
If you have dim, hard-to-see, guage lights; this
mod will go a good way to fix it.

The next thing you'll might notice (after running a
few miles) - is how more smartly the starter spins
at the next startup. Having the extra amps also
keeps the battery(s) charged more completely.

Also: I don't have an electric radiator fan on my car,
but I would imagine that the Fiesta alt has more
than enough muscle to keep one spinning strongly
all day & night without nary a complaint.

Here in the U.S., there is no parts cost penalty for
swapping to a Fiesta alt. In fact, a rebuilt Fiesta
alt is a shade cheaper than a rebuilt Lucas unit
- so that day's lunch is included in this mod.
Daniel Wong

Don of Cornwall:

With the Lucas alternator, on winter days, when I had the radio, heater fan, headlights and wipers on, the red light on the dash would glow dimly. Since I drive the car in commute traffic, this would occur for extended periods. This was annoying to me, as I imagined my battery very gradually draining. Maybe it was never enough to make a difference, but why should I have to even wonder? No other car I've owned had this issue.

When the (second) Lucas unit expired, I opted for the higher output Fiesta unit. It wasn't hard to find, it wasn't expensive and the added output allows me to run all of above accessories without worrying about battery discharge. My question is: When it's so easy to do, why *wouldn't* someone opt for an upgraded alternator? (Unless you're building a show car.)

It is interesting to me that you start your post wondering if the stronger alternator is beneficial, then end it stating that you run the motor at fast idle to top up the battery for the next startup. It seems to me you answered your own question.

I hope you don't take this as inflammatory. I've read your posts often and respect your experience and opinions. I offer this as strictly one man's opinion.

Best wishes,

Matt

Matt Kulka

Don,
The empirical experience of what seems to be hundreds of folks (looking at the counter on my webpage), who have converted to the Bosch unit, seems to validate its choice and use. Many of these conversions, like my own or Danny's or Gerry Masterman's, have now been in use for several years without problems or disasters. I hear very little complaint about the conversion other than the odd sniggle about a fan belt that is now too long/short or having to grind away a small bit on the adjustable bracket to get clearance for the alternator's fan.

You could simply install the later 18ACR Lucas alternator, if originality matters, as I have been told several times by good authorities on Lucas units that it reflects changes to the old 16AC and 16ACR units which bring it in line with the performance and features of the Bosch unit.

The real point to me of converting to any of alternative is better performance in the ways that are important to you and how you drive. Most folks who have converted to the Ford Fiesta Bosch unit (and other options) report that they are well pleased with how their charging system now behaves, and they can go on and concern themselves with other things about their cars.
Bob Muenchausen

Yes!
This is a wondeful conversion. Mine has been on now for about two years.
Why?
'Cause now I have an alternator that has lasted for two years.
Which the Lucas units did not!

Safety Fast
Dwight
Dwight

Hi all.

Having read your comments with interest, I think the concensus is that if you use your car as a daily driver in winter or if your original unit expires, it is worth upgrading.
I will probably get a Fiesta alternator from the breakers and refurbish it over the winter, even though my BGT is not a daily driver, and is taken off the road for the winter.

I do believe that the "run the engine at a brisk tickover for about 30 seconds before stopping" routine is beneficial no matter how good your alternator is, especially in winter.
I also use a mains powered trickle charger occasionally on all of my vehicles, and always get at least 7 years life out of a battery.

Thank you everyone !... Don
Don

Don,
Just for comparison, the Sears DieHard battery in my GT was installed 4/98. It has been kept charged by the Bosch unit alone with no special care or procedures ~ simply driven as an average daily driver does with possibly 3-4 routine clean ups of the battery and battery connections in the meantime. And it is still in the car and still does its job without any sign that it is ready to give up yet.

Not trying to sell you on the Bosch, Don, but I thought you might like to have something to compare your experience to. Yours must be in pretty good order to last 7 years with large chunks of time spent simply sitting over the winter. I am sure that is why the trickle charger has proven so useful, I used to do the same with my MGA which suffered the same fate.
Bob Muenchausen

Hi Bob.

Maybe I am biased.. though I live in Cornwall now, I was born and brought up in Birmingham (England) and my maternal grandfather worked for the Lucas car parts division in the 1940's, 50's and early 60's.

I recall that the employees seemed generally quite proud of the company, and it remains my opinion that genuine Lucas parts were of generally sound design and good quality during that period.

Even my first road vehicle (a bicycle) had a Lucas bell !.

In the 1960's there was quite a fuss when someone realised that having a school next to the Lucas factory making lead-acid car batteries might not be such a good idea, but I think that both the factory (now Lucas-Yuasa) and the school are still co-existing.

I lived fairly close to the Wilmott-Breedon factory, and would sometimes watch, through the always-open windows, the car parts going through the multi-bath chrome plating lines.

That's enough nostalgia for today !.. Don
Don

Don,
I really have nothing against Lucas components, tho lots of Yank britcar owners seem to. I will say tho that I noticed in the 40 years I have been tinkering with cars that there seems to have been a genuine change (upgrade, if you wish) in the quality of Lucas products after about 1962. Not sure why that would have made a difference, but most of my Lucas electricals from that date forward have been as trustworthy as anyone else's. I look at Delco, Mopar, and Philco units I have worked with and find they are all good but actually no better in the long term. However, the Japanese seem to have discovered how to make exceptionally reliable electricals in the mid 60s which I guess spurred the rest to get their products up to snuff.

I did the Bosch conversion originally because it was passed on via this BBS and because it was simple for someone changing from the old 16AC unit of 68 to something better. Hindsight says I could have done essentially the same with the later Lucas 18ACR, altho I am given to thinking that most any alternator would work if a person wanted to fiddle with the wiring enough to get it right. I didn't, so I chose the Bosch and passed on, along with others, how to do it.


Bob Muenchausen

Hi Bob.

Agreed ! I am sure that your site has been really useful for lots of ppl, we need more like it.
I am a great believer in the merits of improvement by modification. I sincerely hope that I didn't give a different impression.

Thank you for your efforts !.

For the record I have no problem with Bosch (or other makes) parts, though I am not sure that parts (brushes, bearings, etc) are as readily availible as recent-ish Lucas parts are here in the UK.
Having said that, I guess most ppl are happy to buy a factory reconditioned unit anyway, so don't need parts. I personally find refurbishing things like a spare alternator, starter motor, distributor, etc, rewarding, (working on a bench is so much more comfortable that wrestling with an exhaust or something under the car !) but I understand that it is not for everyone.

Don
Don

Bob, three years now after the changeover to Bosch. No issues, halogen lights front to rear, high power audio, wipers,fans, fogs and blinkers on, no red light on dash. Thanks to your site for helping this schlep out.

cheers,

Luigi
Luigi

This thread was discussed between 25/08/2005 and 07/09/2005

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