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TR6 76 TR6 Alternator

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FLB76

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I have had my second TR-6 (1967) since 1994 had have had to replace the alternator because of a problem with the bearings. After putting the new one in place, I noticed (for the first time it dawned on me) that there were only two wires on the alternator plug. A heavy brown and a small brown/yellow. There is also a small brown ih the harness, but the female connector is too small to fit on the alternator blade. Should I get a larger female connector for this wire? I have noticed that the alternator warning light does not come on when I start the car, but does when I shut it down.

Frank
 
Actually , I think his fingers move faster than his brain.
His post is titled 76
 
Yes, my fingers were too fast. It is a 76 TR-6 that was built near the end of the production series (CF57005U). Somewhere along the line a DPO removed the air pump and the alternator mounting and replaced it with an alternator that looked to be from a '74 or '75. I have a copy of the TR-6 wiring diagram from Dan Master's book. From what I can recall, before I had to replace the alternator it never had three wires connected and never gave me a problem. After the replacement alternator was installed, the alternator warning light will sometimes glow when the car is started and sometimes it won't.
First thing I guess I need to do is to take the alternators someplace that can tet it to see if it is working. Until I get that chance, should the small brown wire be connected to the alternator?
 
The small brown wire does not need to be connected to the alternator, unless you have one of the (few I think) alternator versions that has a separate small tab for it. It won't hurt to connect it to the big tab (as shown in the above diagrams), it just won't make any difference to the light or anything else.

If the warning light does not come on when you turn the key on (before starting the engine), then I would say there is a problem, most likely with the alternator but possibly in the wiring to the light (the brown/yellow wire on the small tab in the 3-way plug). Could even be the plug itself not making good contact with the blade in the alternator or a break in the wire just outside the plug.

That big brown wire has to carry the full output of the alternator, so if it or the plug are looking a bit "tired", I would consider replacing the plug. (Actually, if it was my car, I would be running the heavy brown wire to both big tabs. IMO even that 3/8" quick connect isn't enough to carry 45 amps for very long.)

O'Reillys will test them for free (at least the ones here will).
 
Thanks for the clarification on the small brown lead. I have removed the brown/yellow lead from the plastic plug and directly connected it to the alternator and it still does not light when the key is in the on position before starting the car. If I ground the connector, the light does come on. We have an O'Reilly's near us, so I will check with them. BTW, should the alternator be on or off the car?

Frank
 
I don't know how O'Reillys does it, but the alternator shops want it removed. They use an elecric motor to spin it up to a very high speed while instruments measure the load and out put. I don't think you'd want to rev your engine up that high in neutral.
Maybe the FLAPS do it diferently.
 
I believe they will do it either way. The off-car tests are probably more comprehensive; but they checked output voltage and max current for me with it (a generator in my case) on the car.

Don't recall the engine rpm, but it was not high enough to be a concern and only took a few seconds. There is really no reason to spin the alternator very fast anyway, unless you're trying to stress-test the rotor.
 
Most alternators will put out there maximum rated amperage by about 4000 rpm. Some need to go to about 5000. That's of course alternator speed, so engine speed is closer to half of that. At our shop, we generally don't go go past 5k rpm unless we think that there is a problem on a returned unit such as a flying short in a rotor. In those cases we run the test manually up to higher speeds.

Of course, modern alternators are getting more complex in their operation and a most of them now have at least some control from the car's computer. We have to simulate all of that on our testers, and of course, each manufacturer has their own ideas on how to go about it. Believe it or not, all of this extra control on how the alternator charges is in an effort to eke out some extra fuel mileage by trying to keep as much load off the alternator as possible.
 
The Lucas documentation says to run the engine at 3000 rpm; probably because some installations use less than 1:2 drive ratio.
 

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you could upgrade to the ford fiests(bosch unit) I think its a 55 amp unit, thats if you have to replace it, but on my 71 TR6, the alt lamp lights with IGN on, and goes out when the car is running so something is amiss, best to trace down wiring, I didnt get my wiring issues resolved till I purchased a new wiring harness, it easy to install too

Hondo
 
O'Reilly's checked the alternator ans said it failed to produce any output. Before I get a replacement, is there any wiring that should be checked to keep another alternator from failing? The one that just failed (a rebuilt) was only about 3 monthd old.
 
FLB76 said:
Before I get a replacement, is there any wiring that should be checked to keep another alternator from failing?
Click to expand...
Just the heavy brown wire to the battery (especially where it joins with the battery cable) and the ground path from the alternator to the battery. Some people have reported trouble getting a good ground through the alternator mount, and added a heavy ground wire from the alternator case to the battery ground cable (but I don't see how you could fail to get a good ground through the mount if the bolts are tight).

FWIW I went through the same thing a few years back on the wife's Toyota. Went through 5 or 6 rebuilt alternators until we found one that would last more than six months. Car wiring was checked several times, all questionable components replaced (including the battery); but on the final go-round the only thing that changed was the alternator itself. That one is still working today (though we gave the car to my daughter). Fortunately the vendor replaced them under warranty, but it was still a giant hassle.

As I see it, the rebuilders are having the same problem with poor quality parts that we have.

PS the Bosch alternator that Hondo mentions is a good alternative. It bolts right up, takes the same plug and everything (but usually does need the little brown wire). However, they seem to have become hard to find recently. All of the on-line vendors that used to carry them don't have them now, and my local FLAPS said they couldn't even order one (although they could send mine out to be rebuilt).

There is also a Delco equivalent, which may or may not be easier to find.
 

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TR3driver said:
As I see it, the rebuilders are having the same problem with poor quality parts that we have...


There is also a Delco equivalent, which may or may not be easier to find.
Click to expand...

Yes, that is a big problem. Everything from bearings, to rectifiers, to voltage regulators. The regulator problem is the worst. We found that in a lot of cases, re-chipping the originals is a better way to go. Most of the chips available are actually of high quality. Most times we have to pick and chose different parts from different vendors to find quality stuff. It's a real headache. Of course, vendors change their suppliers and more often then not,a decent part we were buying is no longer acceptable.

Randall, are you talking about a Bosch offered by Delco or an actual Delco manufactured unit? I'm not aware of any unit manufactured by Delco that replaces the Bosch...that pic you posted is a Bosch. Delco does have their own line of <span style="font-weight: bold">re-manufactured alternators</span>...one of our competitors.
 
Thanks for the reply about the wiring. I was concerned that a short somewhere in the brown/yellow wire may have caused a problem with the alternator.

If I would replace the large brown wire that goes to the odd connector on the positive battery cable, how do you open that connector? Or would it be better to run a new lagre brown wire to the battery post?

After searching on-line, I found a REMY (DELCO-REMY?) unit model 13107 that appears to be a match to the Bosch unit.

Does anyone know of a location in the St Louis MO (southwestern Illinois) area that would do alternator rebuilding to replace failed electrical components?
 
FLB76 said:
...

After searching on-line, I found a REMY (DELCO-REMY?) unit model 13107 that appears to be a match to the Bosch unit.
Click to expand...

Yes, 13107 is the industry Lester number that fits the Fiesta and will replace the Triumph alternator.
 
martx-5 said:
Randall, are you talking about a Bosch offered by Delco or an actual Delco manufactured unit?
Click to expand...
I thought it was actually made by Delco, but to be honest I did not investigate all that carefully. I do see now that the photo I put above is a Bosch with just the Delco logo in the background; so you are probably right about it actually being a rebuilt Bosch. Thanks for straightening me out.

FWIW, Rockauto has the Remy 13107 listed on-line for $73 (plus S&H but with core charge). But they say it may take them up to a month to deliver.

If you go poking around for alternatives, be aware that only Bosch replacements will fit the TR6. The majority of Ford Fiestas used a Motorcraft alternator that will not fit without substantial alteration.
 
FLB76 said:
If I would replace the large brown wire that goes to the odd connector on the positive battery cable, how do you open that connector?
Click to expand...
It has been awhile, but as I recall the plastic cover should snap open with a little prying. It's old enough though that it may break in the process. The connector is considered part of the battery cable anyway; it's not really serviceable separately. About all you can do is inspect for corrosion and maybe clean up the tab a bit.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Or would it be better to run a new lagre brown wire to the battery post?[/QUOTE]
I probably wouldn't, just because extra wires on the battery always looks so amateurish to me. I see TRF has that cable assembly on sale for $25, so that is what I would do (if there is a lot of corrosion inside the cap).

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Does anyone know of a location in the St Louis MO (southwestern Illinois) area that would do alternator rebuilding to replace failed electrical components? [/QUOTE]
Sorry, I don't know of any specifically. But I find that almost any independant auto parts store can send them out to be rebuilt.
 
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