240 100A alternator

jamesinc

Looking to uprate the alternator in the 244 with the e-fan and now an additional pusher fan for the AC.

jamesinc

bump

familyman

You probably don't want to get it from this far away, but I think I saw one on Tradera a bit over a week ago. Do you think it needs more than 80A? (I noticed FCP only has replacement brushes/regulators for 80A alternators.)

jamesinc

My estimates put the max possible load right around 80A. That's stereo loud, wipers on full, main beams and driving lights, radiator fan on high, blower at max speed, rear demister, horn blaring, and lots of shitty wiring connections with resistance across them.

Vee_Que

740 100a mounting points don't match do they? You can use some form of Bosch falcon one iirc.

jamesinc

Can't i shim it or something

familyman

jamesinc;122945 wroteThat's stereo loud, wipers on full, main beams and driving lights, radiator fan on high, blower at max speed, rear demister, horn blaring...

Well, at least we'll know who has the 100A alternator fitted. ;-p

Vee_Que just jogged my memory... I remember reading a thread somewhere, where someone pulled two alternators apart. One with higher current, but he used the back section of the old one to get the same mounting points. No idea where I saw it but pretty sure they were bosch.

egads (she/her)

Talk to an auto electrician and they should be able to rewind your current one for higher output.

Vee_Que

@Angus242164 has the answer on that. I have a 740 alternator and 240 bracket, I'll have a look. The denso unit is way better.

Angus242164

I'm pretty sure 740/940 mounting points are the same in spite of the location and brackets being totally different to a 240, if I'm correct then your best bet is a 940 Denso 100A alternator from a self serve wreckers/somebody here.

What I have done in the past, back when 940's were too new and expensive to be in wrecking yards, was to take a standard 240 Bosch 55A alternator and an 85A Bosch alternator of the same series, and fit the 85A internals and newer generation regulator to the 240 casing, creating a bolt on 85A unit that looks original.

The 85A units are from VN-VR Commodore, TR-TS Magna and early '90's Camry's. I'll probably do this again in future, for my 245L, my 164 and my Kingswood.

DCW242

A 740/940 alternator definitely works on a 240, I've had a denso 100AMP one on my 240 for a few years. There was also a bosch 100amp one used on 940 turbos.

240

@DCW242 does it bolt straight on or does it need some modification?

@Angus242164 is there a reason that you plan on using the 85A swap again rather than using a 100A 940 one?

Just curious as I may well do this on my car in the future.

Actually another question - I have an e-fan in my 240, and when it comes on, the volts drop a fair bit on the volt gauge. If I'm driving with headlights on and rear demister too, the volts are very low. Do I fix this with a higher amperage alternator, a battery with higher CCA, or both?
(Note - I don't know the Amps of my current alternator as the label has worn off.)

familyman

240;123023 wrotewhen it comes on, the volts drop a fair bit

Depends what you mean by a 'fair bit'. But analog gauges are usually wired to work one of two ways:

1. Deflect the needle by sampling current (but actually display it as volts), or,
2. Just connected across a +ve and -ve (so both reading, and displaying, volts).

(I had a look through the circuit diagrams, but couldn't see the wiring for those extra dash gauges. But #2 is more likely.) So if it's dropping from say 14V to say less than 10V, then maybe you have an unhealthy battery and turning those things on really does drop the voltage... Or it's more likely to be a poor connection in one of the circuits you're turning on (including the voltage gauge circuit itself).

In other words test battery capacity. If that's ok and the gauge really bothers you, start checking connections. e.g. There's a bunch of grounds in the dash area. You could confirm this using a multimeter... If turning those things on drops the dash gauge a lot, but a multimeter across the battery terminals does not show a similar drop, then that confirms poor connections.

You could also rewire the headlight switch to carry a much lower current, so it only activates a relay which is mounted closer to the headlights themselves, to reduce voltage drop on that circuit (and produce better light).

240

Turning on the headlights and rear demister reduces the volts by about the amount you'd expect; the issue is that coupled with the efan (which 240s were never designed to run) the overall drop in volts is significant. So I don't think there are any faults. Hope that makes sense.

familyman

As above though... if multimeter terminals 'dug/pressed into' the battery terminals (to give a good connection) doesn't show the same voltage drop - then there's a poor connection somewhere. After all, the gauge is just another type of 'multimeter'. So what shows on one, should show on both. If different, it could be a poor connection, too-thin wires to carry the current on one circuit, poor connection on a fuse, loose ground, etc.

240

Good point - I will try it with a multimeter straight on the battery terminals - but I still doubt that there is a fault, as I explained. (The e-fan has a big power draw by nature, and 240s were simply designed at a time when cars weren't fitted with equipment that drew that much power.)
So basically - I need to know if a more powerful alternator, battery or both, is the answer (even though it's not really a huge issue).

Angus242164

240;123023 wrote@Angus242164 is there a reason that you plan on using the 85A swap again rather than using a 100A 940 one?

I may well use a Denso 940 one on my 245L, as it should be an easy fit as per Duncan's post, but in the case of the 164 and Kingswood, the 940 alternator's mounting points don't line up with the brackets on those cars.

I also have one or two of the 85A alternators here already so the cost for me is minimal.

familyman

240;123028 wroteI still doubt that there is a fault, as I explained. (The e-fan has a big power draw by nature, and 240s were simply designed at a time when cars weren't fitted with equipment that drew that much power.)
So basically - I need to know if a more powerful alternator, battery or both, is the answer (even though it's not really a huge issue).

Not saying there is (or isn't) a fault. I'm just referring it back to what you said about the gauge.

Remember even a small battery can put out a lot of amps. So you wouldn't see much (or any) difference on the gauge between a healthy smaller battery and a new larger battery. You also shouldn't a difference on the gauge between a healthy smaller alternator, and a new larger alternator. Any (big) difference you DID see (on the gauge) would probably be due to 'solving' poor connections by removing/replacing battery/alternator terminals.

So if you want to upgrade to a larger battery/alternator, it sure can't hurt. I've paid $40 extra for a larger battery in the past. Just remember a larger battery won't do it 'better' than a healthy smaller one - it just does the same thing for longer. Same kind of thing with a larger alternator. It would recharge the battery a bit sooner, and provide a bit more current for engine/lights. But the only way to tell if you need them is either to estimate, or actually measure, the current draw of each circuit like James did - to tell if it's needed. (No point buying an 100A alternator, if you have an 80A fitted, but are only drawing 60A - unless you just want to, of course.)

I'm just saying it might not be causing what you're seeing on the gauge. And if you want to find what is causing that, this is the order I'd do things, checking the gauge after each one:

* Check/clean battery terminals.
* Check battery water level. (Only add water before charging if the plates are exposed. And only add so the plates are just covered, because charging expands the electrolyte and it could overflow.)
* Charge the battery (with a 240V charger, not by driving).
* Check/clean alternator connections.
* Have the battery load-tested. A decent place will check alternator output at the same time.
* Check/clean voltage gauge connections.
* Check/clean connections of each circuit that causes the gauge to (significantly) drop.

Vee_Que

Also the quality of the battery is more important than size, ones with calcium and tighter packed lead cells will hold charge for longer and have a higher cca than a cheaper battery of the same size (500-650cca in the case of a 740 battery)