Cooling with electric fans

[peterdpps]

Hi Vegas
Short answer,I think, is yes you would need negative earth and an alternator but I would stand corrected.

[vegas602]

Thanks guys, my car has had a lot of time and effort spent getting bodywork and mechanicals up to very good condition by a previous owner , who only took the car out on fine sunny days. its fitted with OE power steering, which I find ok, but when driving in the dark, the lights noticeably are poor and do dim when the revs ease up! Ive always liked using classics as much as possible and want to use it considerably more, so had thought about an alternator conversion anyway, and it would be nice to be able to fit a radio (not got one at the mo), use sat nav etc.. so had thought about changing to neg earth.Phil

[piman]

Hello Phil,

I suspect an alternator will not make a bit of difference to your lights (Assuming you dynamo is up to scratch). First likely problem is corroded/poor terminations including the earth. Are you still on the original bulb headlamps?
The easiest modification you can do is to buy new headlamp units that use halogen bulbs and fit a relay, along with adequate sized cables, to power them. A relay is beneficial even if you retain your original lamps, as lamps are very sensitive to voltage, a small increase gives a much greater light output, hence my comment about poor terminations. It also has the benefit of reducing the load on the light switches, (They may also also contribute to poor light output due to high resistance contacts).

Alec

[Martec]

If you decide to fit an alternator, don't make my mistake of fitting a 45amp alternator. I blew 3 of them so fitted a 65 amp unit, no problems now.

The load with lights ( particularly dipped or main beam) wipers and heated rear window is quite high, too much in my case for a 45 amp unit.

I can't remember what but apart from a heavy duty wire between the alternator and starter solenoid a few other bits will need changing.

Brian

[piman]

Hello Brian,

that sounds a bit strange, unless you have a lot of other ancillary circuits? Lights 13 amps, wiper 5, heated screen 20? plus ignition etc 5, so a 45 amp should be adequate. That's all my Triumph has and that has an additional pair of 60 watt headlights.

did your ignition light come on when on full load, or the ammeter if you retained it show discharge. (Which is a point as the ammeter is not really rated for an alternator)

Alec

[Martec]

Hi Alec,

Like you I worked out the load and thought the 45 amp ACR (early) alternator would be fine, the first one was a spare for our TC Marina which had been uprated from a lower ampage alternator as they were nolonger available.

But what transpired was that the heated rear windscreen I had fitted was very power hungry (not all are). My local Electrical agent tested the load after the third alternator failure and suggested the 65 amp alternator (easily available in Europe where most of our failures occured), just a lot bigger to fit into the narrow space.

Not so long ago I looked at a kit for an E type and it was fitting the 65 amp unit. The electricians told me that a 45 amp Alt. will supply 40 amps all day but 45 amps only for a short time before complaining ( one pole went down and effectively I only had 1/3 of the charging available, sidelights but no wipers!). The 65 amp is the same 60 amps all day.

These are now old style alternators ie 2 wire as the modern alternators are 3 wire or more, basically the ECU's stop the charging when the car is accelerating so power isn't wasted at that time for battery charging. Hence the old style are cheap £50 to £90 compared to modern car model specific Alternators at £250 or more recon.

So I would recommend fitting the bigger alternator for a negative earth conversion or bigger still if electric power steering was considered.

I didn't help myself by deciding that our power steering pump (hydraulic) needed to be more accessible than the alternator so it is a sod to change as it is mounted on the passenger side engine mounting (unbolted from below then removed from above). An interesting job when done in Slovinia when lying on a piece of cardboard and the use of a borrowed large trolley jack.

Brian

[piman]

Hello Brian,

I hadn't realised that they are not continuous rated, but I suppose that's par for the course with the economy minded car manufacturers.
That's interesting to hear about the reduction in charge when accelerating, but new cars are a foreign beast to me and I do not get my hands dirty on them if I can avoid it.

Alec

[vegas602]

Hi Guys, thanks for the info, will definitely go the route of higher amp alternator if I change the earthing. Alec, the lights were changed by the previous owner to new halogen (H4 I suspect, haven't checked) units. interesting point about switches and resistance etc.. as the dash guage rheostat/dimmer has very little effect on bright ness of gauges, so there may well be a problem there. Phil

[piman]

Hello Phil,

what can be a problem with gauge lighting is dirt inside the glass. Not too difficult to remove the gauges, and remove and clean internally. Slow and a little tedious but probably worthwhile.

Halogen lamps should give a very good light so I think that it is general deterioration in the loom and switches. Fitting a couple of relays and some sensible cable to feed them is a good idea. If you would like a more detailed explanation just pm me with an e-mail address and I'll give you a more detailed explanation if required?

Alec

[vegas602]

thanks Alec, will pm you.Phil