Alternator replacement

[Brenjacques]

Hi all,
Noticed over the last few days that the alternator has started whirring and I think its long overdue for a replacement as it also doesn't 'switch on' until its been revved past 2k rpm. My car is an 85 GTS single carb DX engine and the alternator is the original. I have a Euro car parts local to me and they supply a few types, cheapest being RTX branded, second is a Remy type. Just wondered if anyone had experience with these? Don't want to buy something rubbish that's going to whir from the get go (been there before) and I want one that's going to at least last me a while. Don't know if these are any good? I heard Remy are okay but never even heard of RTX.

[Nate]

Rtx is a no from me. We had one put on the MG. Lasted all of about 200 miles

Delco Remy is a reputable brand, but I've never knowingly fitted one of their alternators

[essextom]

could get yours refurbished.

[Brenjacques]

Thanks for the help, I would have prefered to have got mine refurbished but due to me currently needing the car daily it's not really convenient. I went with a delco, after reading more reviews about RTX type I decided that's a definite no go.

I've since fitted it but now facing an issue. Seemed to work fine when fitted but today driving it at night I've noticed the lights are a bit flickery especially at idle speed. The battery light hasn't lit at all but it looks as if the system is being starved of voltage or current. The old alternator never did this so I'm a bit peeved 'cos it was on a surcharge and my old one has gone! Any suggestions on what to look for? I don't want it going on me all together so need to try and get this sorted out. I'd expect if it is a real problem then the battery light would come on but strange that there is an obvious flicker in the lights.

[GT_II]

If there was a surcharge, I assume it's a recon rather than brand new alternator? If all your connections and belt are tight, it is possible a component on your new alternator is faulty. If it's flickering randomly rather than as a strobe effect, it might be that the new alternator brushes are not fully bedded in. If you're still getting flickering after a few hours of running, I'd ask the supplier for a replacement.

[essextom]

check the earths.

[Brenjacques]

It's a brand new alternator, bought it from Euro car parts but looks like they do a surcharge on all of their alternators. I'll re-check the tension of the V belt. I did give all of the wire connections a clean so they should be fine. I'll recheck everything, check the earthing and give it a week and see how it goes, if it's still playing up after then I'll take it back.

Going to check the voltages on the battery, would imagine it to be about 13.5-14.5v running but can anyone confirm what I should have at idle and revved as I don't have this data.

[GT_II]

You would normally only be asked for the old one back when you buy a remanufactured part, but it should in theory be as good as a new one, with everything checked over and parts subject to wear and tear replaced. The running voltage is determined by the voltage regulator on the alternator and should be pretty static, regardless of revs. Haynes do not list the charge voltage, but I would guess around 14V.

[Brenjacques]

Right, so I've re-checked everything. Earthing is fine, all connections are fine. I tensioned the V belt a bit more and tested some voltages. I do doubt the alternator, on my meter it's constantly unsteable and measuring between DC 13.9-14.5 volts, this was at idle without revving the engine. Find it a bit odd for it to vary like that at a steady rpm so I'm wondering if the reg or alternator itself is at fault. Also checked AC ripple at the battery terminals and again varying between 200-500mV, seems a bit high to me, anyone else think so? Wouldn't imagine there to be much AC at all especially at the battery as it should work similarly to a capacitor and absorb the AC voltage. I'd really only expect a few mV AC to be measured there.

Beginning to think the new alternator is at fault which is really annoying as this problem wasn't here at all with the old one.

[james butler]

checked the brushes?