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View Full Version : TR6 Up-date to Bolt On 72 amp Alternator for TR6



Brosky
02-06-2008, 05:44 PM
Based on Casey's post in my prior thread, this is what I've found.

Update: The alternator info for 72 Amp mentioned by .

Company info https://www.elreg.com

Picture of suspect https://www.elreg.com/product/772.aspx

<span style='font-size: 11pt'>Brand New Lucas part number, less pulley LEA0057</span>

<span style='font-size: 11pt'>Price $115.71 FOB Buffalo, NY
</span>
The sales rep is sending me case measurements to confirm the alternator will fit, but is sure looks it to me.

This is listed in their heavy duty, industrial alternator section. That makes me wonder if there is any static supression built in? I'd hate to listen to a high pitched whine all day.

I think this will require some wiring updates, at least the lead from the alternator to the starter, but if it's a bolt on with no modifications to brackets or harness, it's a no brainer.

I don't readily see the (+) male terminal that's above my (3) connector and the little black box isn't on this one. I've never had one of these apart, so I don't know what's inside that little unit.

tomshobby
02-06-2008, 05:52 PM
Paul, are you considering replacing your new Bosch with this? If so is it because of the new electric fan?

martx-5
02-06-2008, 06:01 PM
That little black box on the outside of the Bosch unit is the regulator. It also contains the brush holder assembly. Most Lucas units have the regulator contained internally, so you don't see it from the outside. Make sure that unit is internally regulated. Also, the radio noise supression is handled by a capacitor. Those are usually internal, and have generally been incorporated in all alternators since day one...but it doesn't hurt to ask.

Edit: Why do you need 72 amps?? That's alot of current. I can't fathom why any TR would need more then about 55-60 amps. That's with the electric fan, the blower for the defrost, wipers, all lights, and the ignition system going.

Brosky
02-06-2008, 06:41 PM
OK Art & Tom, here is my thought process. The Spal 16" fan (ala TR6 Bill) draws 21 amps on startup and levels at 17. I will have my halogen bulbs on in the PL700's at night and whatever else may be running, like heater fan, etc. I do drive with the top down when it's cold outside and keep the heater running. I also drive with my lights on in the day time as a matter of habit.

I thought that the halogens may push it over the edge. I will be installing the Dan Masters headlamp relay package for the lights.

Agree/Disagree? I'm open for suggestions.

Art, I expressed concern about the capacitor as this was listed on the HD side and not all commercial (farm, industrial) have the same components as automotive.

I posted this as information for all. I really don't want to spend another $115 + if I don't have to.

TR3driver
02-06-2008, 07:17 PM
I'm with Art, don't think you need that much.

Unless there's something you're not telling us, like the 300,000 candlepower driving lights or the stereo that can be heard in the next county.

/bcforum/images/%%GRAEMLIN_URL%%/grin.gif

Anyway, I got by just fine with a 55 amp (nominal) Ford alternator in my TR3A, with 100 watt halogen headlights, 16" Hayden fan, and a loud stereo (has to be loud to hear it on the freeway).

tomshobby
02-06-2008, 07:27 PM
Paul, not questioning your choice, just wondering how you came to it. Like Randall, I think it might be somewhat more than needed. I think of all the new cars on the road with the same kinds of components and air conditioning besides.

LastDeadLast
02-06-2008, 07:46 PM
Paul,

I'm running the Bosch alternator with no problems. I've got same accessories that you've got too. I'd only buy the other if you have problems with keeping a charge (You've already bought the Bosch right?).

Why spend the money if you don't have to?

02-06-2008, 07:46 PM
Paul, consider talking to an expert on alternators, perhaps from a shop that does a high quality rebuild. When I took my AutoZone unit it to such a shop for what I thought was a whining noise, they replaced the bearing with some superior quality USA-built ones (at least that was stamped on the bearing) to replace the Chinese units it came with. I asked them to give me an opinion about the rest of the alternator and they maintained that it was as good as it gets. They also bench tested it to determine that it indeed cranked out 69 amps instead the posted 66 amps. He said that this is normal for a unit to show more than it is supposed to. Anyway, catch someone who knows these units and ask lots of questions. I don't feel that 70+ plus amps is too much, especially if you wire it with higher gauge wire (er, thicker, not higher). I wired mine directly to the battery.

martx-5
02-06-2008, 07:55 PM
The only way to really know is to add up the wattage of all the items you will be running. At 14 volts and 72 amps, you have 1000+ watts available. The fan, which draws 17 amps (x14 Volts) = 238 watts. Add up the rest of the constant use watts, and you'll know. I would discount temporary use items such as brake lights and directionals etc. Just remember, the the original TR6 alternator only put out about 30 amps, or less then half the wattage as you're looking at, yet it managed to run everything in the car at the time. My Miata has all the things you are going to be running, plus an electric fuel pump, A/C, electronic fuel injection and a number of other electronic gizmos...yet it runs fine on a 60 amp alternator.

Brosky
02-06-2008, 07:56 PM
Bill,

I think that I confused the situation. I apologize if I did. I don't have any issues with my "new" Bosch installation. It (and my old locally rebuilt Lucas) work just fine.

I mentioned the "whining" only because I thought that if this were an industrial unit, less a capacitor for static suppression, that I might have a whining while driving and listening to the radio.

I just thought that this would solve any power issues, but if the consensus is that the 55 amps will be fine, then I can always replace it later if there's a problem with the 55 amp unit charging enough. Actually, now that I think about it, it was Bill at Ron Davis Radiators that suggested getting an alternator with a higher output than 55 amps.

Brosky
02-06-2008, 08:02 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Paul, not questioning your choice, just wondering how you came to it. [/QUOTE]

Tom, so far I really like what I have. If Casey hadn't posted the picture of the 72 amp earlier and if I wasn't trying to kill an hour at the office waiting for some return calls this morning, I never would have had time to dig into this other option.

I think that my new 55 amp will be fine. If not, I know where to get a bigger charger.

What was that old expression, "Idle time is the devil's workshop"? I should have stayed busy this morning!! /bcforum/images/%%GRAEMLIN_URL%%/nonono.gif

piman
02-07-2008, 01:59 PM
Hello Paul,

that fan is very high wattage?. But how often will it be running (if at all, when it is cold and you have the heater on). My electric fan only runs in slow traffic in summer and then it switches in and out.
No real problem with such a large alternator as long as the cables are also uprated. You realise at full load that alternator requires 1 1\2 to 2 HP to drive it (depending on losses) :-)

Alec

RobT
02-07-2008, 03:14 PM
The original wiring is only designed for the 37(?)Amp Lucas alt. Plonking in a 70+Amp alt could overstress the good ol' Lucas wires a bit, and the ammeter (35A I think?) too. An upgrade to some of the wires might be a good idea if going the full monte on an alternator.

Rob.

Brosky
02-07-2008, 05:35 PM
I'm gonna hang at 55 for now. If I need it later, I'll get it down the road.

Opa
02-07-2008, 06:18 PM
hey all I think I should clarify my original post some what.

Paul, I am in no way questioNing you're decision of alt. choice or anybody else's choice for that matter. My question was has anybody used or looked into a higher output Lucas unit that uses the same mounting,wiring etc as OEM,.nothing more intended or implied.I'm sure one is as good as the other as my original has been making juice for 18 years and a little over 80000 miles,like a Timex, keeps on going.

Being that I live in an area which is mainly agricultural, I have seen many tractors with Lucas alternators with identical units as on TR'S up to about 55 amp.International Harvester,Nuffeild, Massey Fergusion to name a few , and many industrial unit's. Some the front housing would have to be clocked to fit.
On the road you would never be stuck for an Alt. if the Napa Store does'nt have one for TR6,Just ask him to look up a afore mentioned tractor that had Lucas on it.Most parts books will tell you what it had.BTW Bosch was also used on aforementioned rigs.Why you ask,just like your car units interchangeable.
PIMAN i agree with you in that the 72 amp. alt. requires a bit more to turn but that would only be at it's max output which for all intese and purpose would likely be short term,as in a stone dead battery,or many driving lites have been added, along with a 500amp boom box or towing a mobile travel trailer,which for most of us is unlikely.But there again if OEM cooling fan is removed from crankshaft you would gain probaly 4-5 hp leaving you a net gain of 2hp.
Rob T
as to the original wiring IMO not that big a deal on the late cars with a volt meter,again if the vehicle is basically stock with the addition of a fan and a set of driving lights.On the the early cars with an ammeter I would be some what hesitant to run that kind of amperage thru the gauge even short term.
Just for comparison sake have a look at a late model domestic automobile and compare wire size,not that much difference,and most of your domestic well equiped cars run an ALT. of 100 + amps, that's what's on my wife's Pontiac GranPrix GTP.
Hope this clears up some of the confusion.

poolboy
02-07-2008, 06:35 PM
Am I mistaken, but doesn't an alternator produce only the amps that is called for as opposed to a generator?

TR6oldtimer
02-07-2008, 06:43 PM
Am I mistaken, but doesn't an alternator produce only the amps that is called for as opposed to a generator?
Both generators and alternators are on demand devices and provide power as needed.

LastDeadLast
02-07-2008, 06:46 PM
Poolboy,

You are correct. The problem.. in the case of our 30 year old + wiring is that it wasn't designed for the out put of a newer alternator if your battery is drained. So unless you upgrade the wiring, you run the risk of melting your electrical system.

poolboy
02-07-2008, 06:55 PM
LDL, I sure can't afford for that to happen!!

martx-5
02-08-2008, 05:28 AM
Poolboy,

You are correct. The problem.. in the case of our 30 year old + wiring is that it wasn't designed for the out put of a newer alternator if your battery is drained. So unless you upgrade the wiring, you run the risk of melting your electrical system.



The output of the alternator is going back to charge the battery...that is the only part of the wiring that needs to be upgraded with a heavier gauge wire. The extra amps are going to charge the battery. If you change any other items in the car, such as higher wattage lights, then that wiring has to also be upgraded. You don't have to upgrade the whole system, only those parts that are affected by equipment changes you make in the car. For high wattage items, relays are best, as the original switches can't handle the increased amps. Of course, there is some debate about whether the original wiring and switch gear was even adequate when the car was new! /bcforum/images/%%GRAEMLIN_URL%%/hammer.gif

PeterK
02-08-2008, 09:48 AM
I agree. I fit a 63 amp Delco unit on my TR3a and, instead of running the charge through the 30amp gauge, I ran the output directly to my battery + terminal/starter solenoid hot. I used 8 gauge wire. So none of the dash, etc. gets the full amps of the alternator. I have a volt gauge for my 4a with the same setup.

Also agree re:relays for add-ons to your system. Relays isolate the fragile switches from increased amps required for the uprated lights, stereo amplifier, electric fan. Also give you full power to the devices, reducing voltage loss.

So bolt-on isn't totally bolt-on, you also have to do the wire from the alt to the batt.

Brosky
02-08-2008, 10:22 AM
The only process difference that I see with some of the above suggestions, is that both Dan Masters and the alternator manufacturers recommend running a new 8ga wire to the starter solenoid, rather than directly to the battery. I happen to agree with that logic. I also have a voltage gauge, so the charge reading issues that occur with amp gauges don't affect my car.

So, while it's technically not a 100% "bolt on", I was referring more to the R&R of the alternator itself, as apposed to the alternator case and bracket mods needed for some Delco swaps.

RobT
02-08-2008, 10:36 AM
I agree. I fit a 63 amp Delco unit on my TR3a and, instead of running the charge through the 30amp gauge, I ran the output directly to my battery + terminal/starter solenoid hot.


But then dosn't the ammeter always register (-ve) "drain"?

Agree - its only the wires from the alt to the ammeter and then to the starter solenoid (brown and brown/white as I remember) that are sibject to overload, and then only when the battery is charged. Fusing & relaying any additional circuts (fans, driving lights, air horns) a must too. Don't want that expensive Lucas smoke leaking out!

martx-5
02-08-2008, 12:40 PM
I'm installing Dan Master's wiring harness in my TR3. The issue with the ammeter he deals with in a couple of differnet ways. One is, of course, use a higher rated ammeter. Another is to put in a 12 gauge shunt. The ammeter will read approximately 1/2 the current, but everything won't be going through it.

Brosky
02-08-2008, 05:41 PM
The alternator pictured above (72 amp) does have an internal voltage regulator, but has NO static suppressor built in.

"Stayin alive at 55" for now.

Remember that catchy little phrase for the gas crunch era of the 70's?

martx-5
02-08-2008, 06:32 PM
The only thing that is used to suppress alternator whine in radios is a small electrolytic capacitor. They are normally around 0.5 uF. That can be easily attached to the outside of the unit like Bosch does on alot of theirs.

PeterK
02-08-2008, 06:53 PM
I agree. I fit a 63 amp Delco unit on my TR3a and, instead of running the charge through the 30amp gauge, I ran the output directly to my battery + terminal/starter solenoid hot.


But then dosn't the ammeter always register (-ve) "drain"?



Rob

A. - yes. That's why I fitted a volts gauge in my 4A. But on the 3A, the needle still moves but on the - side.

I connected to the + side of the solenoid mainly because it was easier to make look clean. Didn't realize that it is preferred.

02-08-2008, 07:50 PM
If the idea of an alternator is to keep the battery charged, what purpose does it serve to connect a high-output aftermarket alternator to the starter when the purpose is to charge the battery, and not the starter. The battery's duty is to kick the starter over, not the job of the alternator. I found one of those multi-connector positive battery post connections and rewired my whole stock harness in this area with an 8 gauge wire. The big wire from my Delco-style 66 (really 69) amp alternator goes directly to my Optima battery and the wire to my high-torque starter is of equal size. I insulated the whole thing with a super-heavy-duty shrink tube. I also have my Spal fan wired direct to the battery (with its own GM-style fuse from Spal, inline), so I have 3 connections to the battery.

Am I wrong. No smoke yet.

poolboy
02-08-2008, 09:11 PM
I wondered the same thing. The starter and alternator are on opposite sides of the engine on a TR6; so why go to the starter even though the starter is wired to the battery? That just seems like taking a longer route. What am I missing?

PeterK
02-08-2008, 09:28 PM
On the TR3a, the starter solenoid is mounted on the bulkhead shelf to the left of the + terminal of the battery. About 12" or less.

It's already direct connected to the batery + terminal with the battery cable. I wouldn't think that there's much loss over the large gauge 14" long battery cable.

Brosky
02-08-2008, 10:52 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] I wondered the same thing. The starter and alternator are on opposite sides of the engine on a TR6; so why go to the starter even though the starter is wired to the battery? That just seems like taking a longer route. What am I missing? [/QUOTE]

I really don't know the answer to that, but I'm not a wiring whiz, so I know that I'm not qualified to answer that question accurately from my built in knowledge base.

However, I do remember reading back on one of the electrical threads here on the forum, that a direct wire from the alternator to the battery was bad for one reason. That reason was, that in the event that the battery went dead and the alternator was to pump out full charging, it "could" melt down the wiring between the two.

I could be wrong, but that's what I seem to remember reading either here or on the 6-Pack forum.

PeterK
02-08-2008, 11:15 PM
From what I know, alternators don't play well with a dead battery like generators do.

So maybe this has something to do with having an indirect route from the alt to battery. Not sure how it really differs though. It's the same cable just the other end.

Opa
02-08-2008, 11:45 PM
check the wiring schematics on Advance wiring web site for your particular car under stock wiring and you will see that the alt wire(brown on a late 6) goes directly to your battery cable about midway between batt. and starter.If you go directly to starter with your new wiring you eliminate the possibility of a problem in that particular connection,but you would be making the same connection.

Alt. has nothing to do with starter, just sharing a connection and using batt,cable to charge battery,when engine is running as soleniod is dormant until key is turned and solenoid is energized making connection to starter motor. hope this helps .....

TR3driver
02-09-2008, 01:15 AM
Since the battery clamp is normally not designed to accept side connections, the starter solenoid makes an excellent place to connect other high current devices to the battery. It already has a very heavy gauge cable, capable of handling hundreds of amps, connected directly to the battery. The starter has no other relationship to the alternator (since they are active at different times) except as another high current device connected to the battery.

That said, I routed my 60 amp Ford alternator through the stock ammeter on my 59 TR3A, with the stock wires (and a shunt as Art mentioned). Worked great for nearly 20 years; no signs of overheating or any problems at all. Using the original control box as a junction probably was a poor idea, it only lasted some 15 years in that configuration.

But, I created a new tie point in the new heavy gauge wire from the alternator to the control box, to tie other high current devices into. That means, under normal circumstances, the current to operate the radiator fan, headlights & stereo went directly from the alternator through the new tie point and to the new devices. The existing wires only had to carry current when the battery was being charged, or was supplying power to run the devices.

FWIW, the stock charging circuit on a TR3A is considerably heavier gauge wire than my Chevy with an 80 amp alternator had. It's in no danger of "burning up".

TR3driver
02-09-2008, 01:29 AM
From what I know, alternators don't play well with a dead battery like generators do. A myth, IMO, albeit a popular one. Alternators are inherently current limited, and should be able to operate at full current all day long. Again IMO, the fable about them not being able to charge a fully discharged battery is mostly spread by rebuilders (and their resellers) offering excuses for their shoddy work and inferior materials. Automotive grade diodes will take the heat, but cheaper, industrial grade components won't.

And actually, the TR generator setup IS somewhat sensitive to a deeply discharged (but still low resistance) battery. That's because generators are not inherently current limited, and the TR setup uses a single relay to control both current and voltage. If the battery voltage is very low, it will let the generator over-current to some extent.

martx-5
02-09-2008, 07:20 AM
From what I know, alternators don't play well with a dead battery like generators do. A myth, IMO, albeit a popular one. Alternators are inherently current limited, and should be able to operate at full current all day long. Again IMO, the fable about them not being able to charge a fully discharged battery is mostly spread by rebuilders (and their resellers) offering excuses for their shoddy work and inferior materials.

This was true in the past with alternators such as Delco's 10SI unit. But with modern alternators, the package may be the same size as a 10SI, but capable of twice the amperage. The heat build-up is just too great for them to run full bore for an extended period of time without components failing. As far as why rebuilders (and I work for one) say not to use the alternator for charging the battery has nothing to do with shoddy workmanship or inferior parts. It has to do with the fact that when the battery is fully discharged, voltages from the alternator can rise significantly, and this can play havoc with modern car electronics. It's the reason that many OE manufacturers are now installing avalanche (zener type) diodes in their units to control this over voltage. It's stated as a precaution against fried electronics.