TR6 New Alternator Rec.

Hello forum,
I Have a shorted volt reg on my 1973 tr6 alt. Does anyone have a recomendation for a replacement Alt. I am not opposed to wireing a new plug on, just want to make sure bolt holes and pully line up. I would like a little higher amp say 60 or so. I have heard some GM alts would work, don't know which model #. Any help would great. Thanks

Not sure how available they are now, but there is a Bosch alternator that bolts right up, same plug and everything. Original application was 78-80 Ford Fiesta with AC (or with Bosch alternator). Don't be fooled and get the Motorcraft alternator, it doesn't mount the same.

Rated 55 amps as I recall, but delivers it at much lower rpm than the old Lucas does. We put one on a buddy's TR6 and it would keep up with his high power stereo at idle. Don't recall for certain, we might have had to move his old pulley to the Bosch.

I believe you can also buy replacement regulators for the old Lucas.

Thanks TR3driver, haven't looked into a regulator replacement yet. Not sure if I even want to keep the lucas, sounds like maybe a bearing is about to give also.

Here's the Fiesta on my 74..Pretty much a plug and play although the fan belt is 1/2 " longer than the one you see in the TR6 parts catalog for the 74.

The application is for 78 to 80 Ford Fiesta with A/C and rear window defrost.
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Here's the GM 7127 in my 73.

A few more mods required, but it's availability and lifetime warranty from AutoZone make it attractive.

I was doing a little research on this myself over the weekend and found this site from Paul, which I think is pretty useful. Give it a go:
https://www.74tr6.com/alternator2010.htm

+1, or +2 whatever it is, on doing the upgrade. Very useful improvement.

I bought the 110 amp alternator from rareelectrical.com on eBay. The fit up was easy and it works great. Minor mods to the mounting bracket. Slightly longer belt.

https://www.ebay.com/itm/400313494637

If you do go the Bosch 55 amp route, don't make the mistake I did, make sure that it comes with a fan and pulley before plunking down your money. I did this many years ago and found out the hard way that it was a tough size to match up (at least at that time) and of course, the one I bought had no fan or pulley included. I wound up going junk yarding online to find a dead Fiesta with the correct alternator just to get a fan and pulley. A couple of hour drive later and I had it but I don't know how much luck you'd have finding one today, those old Fiestas weren't all that common then and are all pretty much out of the system by now. From a Ford and Bosch perspective, they were NLS when I was looking for them.

That's a good point about the Bosch. I brought the fan and pulley from my Lucas to a machinist to enlarge the holes to fit the Bosch shaft..I believe he charged 12.00.

bunzil said:

I was doing a little research on this myself over the weekend and found this site from Paul, which I think is pretty useful. Give it a go:
https://www.74tr6.com/alternator2010.htm

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I second this! I have the Bosch 55 amp and it's not quite enough when driving at night in the rain with the radio on. 55 is marginal. I'd go with 95 amps or better.

Pan,

I got a Bosch from Amazon several years ago. The PN is 13107 and looks like they have one now (https://www.amazon.com/BBB-Industri...d=1404512853&sr=1-1&keywords=alternator+13107). But the 1-star feedback from the Amazon buyer confirms what Tybalt said - no fan or pulley. I enlarged the fan with a file and found a metric-spec pulley on eBay. And like Poolboy says, you'll need a longer fanbelt.

Jeff

Thanks everybody for the suggestions, I am considering the 110 amp by Rareelctrical, I know its a bit overkill but has the pulley and just needs minor wire in. Not sure about bracket. Rustbucket say minor modification. We will see..

If I recall correctly, all I had to do was grind some off the boss where the tab that the mounting bolt goes through to line up the pulleys, and clearance the front plate on the engine a little. I'll take some pics next time I have the hood up, which is pretty often!

Correction, the "bonnet" up!

Check out the 2 Alt replacement articles Paul rego Did.
You need to find the newest one which is a 95 Amp somewhere on his page
https://www.74tr6.com/

So, I bought the Rareelectrical 110a I can't quite understand if I am wiring the unit correctly. I did have to shave the spacers a bit, but mounted up real nice. As of now I can not get a charge to the battery, volt meter shows less than 12 when engine running. I though the instructions were clear, but they did not say what to due with the small separate brown plug from the existing alt. I have a 73' with 2 large brown and 1 small brown/yellow on the plug and than a separate small brown plug.
The instructions said to combine the 2brwn with the red wire from the new alt and attach to the bat lug on back of alt. Than attach my brn/yellow to the 2 brwns on the alt plug. and leave the grey as acc. No mention what to do with my other small bwn plug? I know this is a little hard to visualize without a picture, I will try to take one.
I noticed none of the wiring diagrams show the 4th wire with separate plug going to the original alternator. Can someone tell me what this was for?
Thanks
Brian

PanP said:

I noticed none of the wiring diagrams show the 4th wire with separate plug going to the original alternator. Can someone tell me what this was for?

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Check page 86.00.02 in the workshop manual, I believe it shows the extra wire. I believe it was the "sense" wire, that lets the voltage regulator "see" a more accurate picture of battery voltage (without being fooled by the voltage drop through the main output wire).

From the description, I'm pretty sure you don't need the old sense line. Just tie it back and insulate it, so it can't touch anything. It's wired directly to the battery, so it will let the smoke out if it touches anything.

Linking either one of the big brown wires to the red wire and the output lug on the alternator should be enough to make it work, at least a little bit. Sounds to me like it has gotten damaged somehow and no longer works. You might take a voltmeter or test light and double-check that you can see battery voltage at the lug, with the engine off. It's possible (though not likely I would think) that there is a problem where they attach to the battery cable. Also worth checking that the voltage at the lug doesn't go up with the engine running at fast idle.

PS, I don't mean to say that you shouldn't wire both big brown wires to the output lug; only that it should work some even with only one connected.

Turns out to be a bad Alternator. Sent it back to Rareelectrical for a replacement. They were very responsive and easy to deal with although I did have to pay for shipping to return the defective unit, one of the downsides to buying online
New one should be here this week hope I have better luck. If all else fails I will be getting a common Delco from Oriely Auto and modifing the mounts to make it work, probably should have done that in the first place.