alternator

[nick]

My '79 7 is fitted with a Lucas LRA 101 alternator. Rimmer sells a 17 ARC. Mine is a three wire. The LRA 101 on my car is barely showing above the min line on the gauge. When I add services the bat voltage drops and the gauge goes into the red. I have a rebuilt Lucas on my shelf. It's a three wire from a TR7 but one of three posts is very wide. I will have to get a new connector but don't know where to get one that wide. Also, does anyone know which wires go on which post?

nick

[jclay (RIP 2018)]

The Brown wire in the middle goes to the starter. The other large brown wire goes to the black terminal on the Red battery cable. The thin brown/yellow connects to the small lug and goes to the charge indicator light in the dash.

Why not install the Saturn alternator. Download instructions from my download page. Link at bottom of post.

jclay

[url="http://web.mac.com/jclaythompson/iWeb/Site/Welcome.html"]My Triumph Site[/url], [url="http://web.mac.com/jclaythompson/iWeb/Technical/Intro.html"]Technical Stuff[/url], [url="http://homepage.mac.com/WebObjects/FileSharing.woa/53/wo/HJMTK8gsojtwKleP.1/0.2.1.2.26.31.97.0.35.0.1.1.1?user=jclaythompson&fpath=Triumph_Articles&templatefn=FileSharing4.html"]Download Page[/url]

[PeterTR7V8]

JClay, what is the function of the wire going to the starter? The middle connector on my 3-wire alty isn't connected.

I have learnt to disconnect the battery or put tape around the top wire connector whenever I disconnect it as it tends to short quite spectacularly when it touches the block. Damn thing makes me jump every time!


Never say die. At least not while you're still breathing.

[nick]

The Saturn Alt is certainly an option. However I scored a used Alt a couple of years ago and had it checked and cleaned along with new bearings installed. So I would like to use that one until it craps out. My only impediment is aquiring and wiring in a pigtail or set of connectors to fit it. There's a guy in Ohio that has TR7 parts but I can't think of his name. He may be able to snip the connectors off a 7 and send them to me.

nick

[cliff]

Peter, if the battery lead you disconnet makes a large arc and spark, it sounds to me as if you have disconnected the hot lead which will arc and spark when it touches anything. The black lead to groung/earth is the proper lead to disconnect. This lead should be routed to ths chassis or engine. If the ground/earth lead makes a mojor sprak, you may have a bad short somewhere in your electrical system
Cliff[8D]

Don't use force, get a bigger hammer!!

[nick]

Comparing the Haynes elec diagram to my car makes me suspect major wiring changes. The two brown wires that should come out of the Alt are white and are spliced together. From there the single wire goes up to the Red Bat wire. The start motor has the Bat red wire and a white wire which I suspect comes from the start relay. No other wires on it. It all works with the current Lucas Alt so I just dropped it off for repair. I'm not sure my used Lucas that I have on the shelf will play with this setup.

nick

[jclay (RIP 2018)]

The brown wire that goes to the starter is the wire that charges the battery. The brown wire that goes to the middle connector on the battery is the one that monitors the battery and tells the alternator whether to charge or not.

This is VERY important in the TR8 electrical system! The connector in the middle of the main battery run is located under the carpet in the passenger's side footwell on the TR8 and it has a tendency to corrode. (Image!) Because it is never seen, most owners don't believe there is a connector in the run. When it corrodes, the alternator thinks the battery is discharged and will continue to charge. This causes premature failure of the alternator.

There is a service bulletin about this problem and the fix is to connect both Brown wires to the starter terminal, which shortens the run to the alternator and does away with the increased resistance caused by corrosion problem.



jclay

[url="http://web.mac.com/jclaythompson/iWeb/Site/Welcome.html"]My Triumph Site[/url], [url="http://web.mac.com/jclaythompson/iWeb/Technical/Intro.html"]Technical Stuff[/url], [url="http://homepage.mac.com/WebObjects/FileSharing.woa/53/wo/HJMTK8gsojtwKleP.1/0.2.1.2.26.31.97.0.35.0.1.1.1?user=jclaythompson&fpath=Triumph_Articles&templatefn=FileSharing4.html"]Download Page[/url]

[nick]

Took the LRA 101 Alt to the electical shop. Checked out perfect. When will I learn to trouble shoot the simplest things first. On my car the two wires that come out of the alt are spiced and go to a connector which joins them to the Red (positive) battery cable. I found that connector had corrosion and was slight lose. Cleaned and tightened and it all works fine.

nick

[Cobber]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by nick</i>

Took the LRA 101 Alt to the electical shop. Checked out perfect.

<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

<font size="2"><font face="Comic Sans MS">Now Nick, I hate to be the bearer of bad news mate, but you are going to have to remove that alternator from your car and put it on display in a museum!
As it is the sole example of a fully functioning Lucas alternator in the world! </font id="Comic Sans MS"></font id="size2"> [:D]

80'Triumph TR7, , 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
85'Alfa 90, 69'Ford F250.
76' Ford F100

[nick]

Yeah, you're right. But to my knowledge this LRA 101 was not used on the TR7. I think it puts out 34 amps and is much smaller than the ARC that I have on my shelf. Although I think that spare is the big one used with AC cars. It looks like this one went in with no braket mods. The wiring has been moded so that the two wires off the alt are spiced together and go to the positive bat cable.

nick