'93 440Si Alternator Shenanigans

'Ello folks! First post and all that, and although search has brought up some relevant info, I've not quite found exactly what I was looking for. So, bear with me please...

I finally bought myself a Volvo 440Si last week. She Who Must Be Obeyed has been raving about how good they are as she had the 2.0i 440 a good few years ago and loved it, so after seeing one in amazingly tidy condition, only 70,000 genuine miles and with a brand new MOT for only £300 I couldn't resist. It drove/drives lovely, nice and quiet, surprisingly nippy and lovely and comfortable. It even came with over half a tank of juice.

So far, so good. Just a few minor niggles, 2 illumination bulbs out in the instruments and a randomly-working rev counter.

Until 100 miles or so later..

Coming out of Morrisons with the shopping, and upon starting the car, I notice the battery light was not going out. Swine, failed alternator I thought. However, it was not just the battery light. The brake warning light, temp warning and low fuel light were also lit, but not as brightly as usual. Brake warning, for example, is fully lit with the handbrake on, but noticably dims to the same level as the temp/fuel light.

With these other lights illuminating, I was hoping against hope that it may have been a malfunction behind the instruments. I had a slight fiddle with the Valeo alty, and upon taking the warning light wire off all lights were extinguished. I forgot to check by taking the wire to earth if that would just illuminate the battery light or if it would illuminate all the aforementioned lights but anyway, a knackered alternator seems to be the problem.

Upon searching around, it seems that in some cases more than just the battery warning light will illuminate, apparently to help draw attention to the fault. Is this true?


Just to check it was not summat in the instruments, I put my trusty meter upon the battery, and found no signs of charge whatsoever.


Whilst doing all this, I found the (trumpet blast) *MEGAFUSE* in line from the alternator to the battery, and according to the meter it had blown not quite open, but to the tune of 8KOhms. Testing with the engine running I had 12V on the battery side, 0V on the alternator side. I also tried bridging the fuse for a short period, to be rewarded with a shower of sparks.

So, also looks like the alternator has blown short circuit, so in hindsight, huzzah for the *MEGAFUSE*.

So, finally, I come to my point. Does a shorted alternator indicate mere regulator failure, (easily replacable and cheap from what I've read), or would this be a more serious (read expensive) diode pack/rectifier fault? My suspicions are with the more serious one, but as money is tight as hell for the next two weeks, the cheaper I can make the repair the better.


I have a written off Clio deisel outside, and I notice the alternator upon that is the same make, although slightly differerent wiring, with an extra wire attached. However, I believe that extra wire runs the rev counter. Provided the mount is the same and the pulley is the same diameter, I imagine I could get away with using that for the time being.

Seeing as alternator failure appears to be one of the more common faults with the 440/460/480 series, is there a more reliable unit that can be fitted? I believe certain Bosch units will work, for example. Is the Bosch unit more reliable than the Valeo? What other cars can I take the alternator off and that'll fit without any headaches?


Finally, huzzah for plenty of space in the engine compartment, and double huzzah for the alternator being easy to get to. My knuckles are rejoicing as I type...



Cheers in advance for any hints, tips, general advice ect.

Update.

Well, a diesel Clio alternator can be persuaded to work on a 440. I have proof!

Slight wiring difference, the Clio alternator appears to need an extra ignition-switched live to energise the field coil in order to start charging. I did think I could get away with a temporary live just to get things going (idea was to send this live via the starter solenoid, in order to fire the field up just enough to start it "self powering", but alas no joy. Even when running and charging at a healthy 2000rpm or so, removing this live removed the charge..)

So, switched live it is for now. The pulley size is slightly larger on the Clio unit. Not enough to need the belt changing, but just enough to ensure the 10mm tensioner bolt does not line up with that metal block, so back to tensioning the belt the old fashioned way, levering a nice hefty length of wood onto the alternator body with one hand whilst nipping up the bolts with the other.


You might ask why I'm letting myself in for all this guerilla mechanics, but I'm on the bones of my bum with regards to money for the next week or two, so something had to be done so I can remain on the road until I have the spare cash for a proper replacement alternator.


Anyway, huzzah for all the space under the bonnet in the Volvo. It took about an hour in all getting the alternator off the Clio, no room whatsoever to work in and the radiator/air filter block has to come out in order to get the swine out. Compare this to about 5 minutes taking the alty out of the Volvo..


End result for all this faffing around, a usable charging 440Si again. I'm a bit nervous having no *MEGAFUSE* in line at the moment, the Clio never had one in line, but I'm sure I've got a 75A mains fuse knocking around the shed somewhere, and the Clio alty is only rated at 60A I seem to recall, so I'll put that in line for now. Better than nowt I suppose.


All part of the fun.