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Which Alternator Do I Need???

westie47

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After doing some research on here I am still confused about which alternator I need. There was no original to use as a reference

Single wire or two wire?
Single groove or double groove?
How many amp? 60? 75? 90? 110? Can you have too much amps?

Going on a 69 Coronet, 440 auto, Mopar electronic ignition, no AC, power steering. The ammeter has been fireproofed. The wiring harness is a stock replacement designed for electronic ignition. I'm thinking Power Master, Tuff Stuff or the Mopar one.
 
You'd need a square back 70s to 80s Napa or whatever single pulley 60 Amp. Or there abouts
 
Those generally aren't stock. Now you're talking the big chryco ones you can weld with. About a 20 lb er.
 
If you don't have much accessories, stock ones were low amps and were fine.
 
If you're not picky about pure stock, Power Master is really good. I bought a Tough Stuff but haven't used it yet.
 
I see you're in the truckers country,, do you got a parts source around there.
 
I'm not picky, I just don't know which one to get...


I've had one in a car (in my avatar) since 2014, absolutely no problems. They're starter motors are also fantastic. they're not cheap but it's worth it. I have the starter motor in a 440 six pack and as soon as the key hits, it starts.
Look them up and see what's available. I bought a square back two wire but it doesn't matter, you can still use it.
 
If you stroll in there and say(to the commercial salesperson ) I want a 74 charger 440 no ac , alternator, single groove, 60 ish Amp. See what they come up with.
lol yes of course we do.
 
If you go to a high amp. alternator, you should upgrade your charge circuit wiring from 12 ga. to 8 ga. With no heavy amp. draw accessories like A/C or cooling fans, you should be good with factory 60 amp. single pulley 2-wire, without having to upgrade wiring. I have noticed that some rebuilders are putting dual pulley on everything.
 
69 is a single field round back, 70-71 is dual fuel round back, 72 and up is square back. On a 69 you would only use one terminal if you buy a generic with two field terminals. Don’t buy a china reman or China new one, get a good rebuild from a local rebuilder unless you want it to show correct then contact Jim Ridge @ Dixie Restoration. Stock output would be fine for you imo.
 
You need an alt able to feed all your accesories at iddle or closer at iddle as posible without require power asistance from batt ( discharge reading on amm ) and geared with brakes pressed if posible.

The alt will provide the load requested by the car ( just like battery does too ), not its max output rated by the manufacturer.

Consider EVERY electrical device on the load maths being turned on as a constant sucker and everything at the same time... wipers ( high speed ), radio, parking and headlights, ignition system, A/C or Heater at high speed ( blower is the problem... and the iddle decay if A/C makes it worst )... rear deffog.

Blinkers, cigar lighter, glove box light, map light, dome light, brake lights, power windows are not a huge problem since they just tun on occasionally and the recovery capacity uses to be fast enough, but the rest are a headache.

On my experience something into 45-55 amps rate at iddle could be nice to be safe from huge headaches most of the time. But if more... better.

This is not a math rule ( just a guide ) but TIPICALLY the iddle output rate on the original design used by Mopar ( Y winding stator ) uses to be at around 55-60% from the max output which is the normal spec given by manufacturers. So a 100 amps alt could be into the 55-60 amps rate at iddle. This varies also depending on pulley size of course.

Aftermarket performance products uses to be on better rates thought.

Single or double groove? Back in the days, tipically double groove were an indicator for AC cars giving better output. Not anymore nowdays. Just match your belt setup since can be ordered per your needs.

I'm toward to the stock ( external ) regulator setup. Easier to service in case of failure AND you can also full field the alt in emergency case on the road. Not recomended but posible and you will be saving the emergency.

I'M NOT A TECH, JUST SHARING MY EXPERIENCES and thoughts.
 
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Need to add, the revised squareback versions ( lates 70s and later alts ) are a bit wider than the older alt versions by a couple of milimeters or so. Pretty sure those aftermarket units based on these alt desgn are too. This could be a problem on some engine setups. It was on my 74 400 A/C where I had to trim a bit the rear spacer and get a bit longer belt because the back of the alt met the engine.
 
After doing some research on here I am still confused about which alternator I need. There was no original to use as a reference

Single wire or two wire?
Single groove or double groove?
How many amp? 60? 75? 90? 110? Can you have too much amps?

Going on a 69 Coronet, 440 auto, Mopar electronic ignition, no AC, power steering. The ammeter has been fireproofed. The wiring harness is a stock replacement designed for electronic ignition. I'm thinking Power Master, Tuff Stuff or the Mopar one.

OUT OF CURIOSITY, WHY do you think you need a high current alternators for a relatively stock application? Contrary to others comments, NOTHING will be gained by using a 110 amp alternator in lieu of the stock or origional capacity alternator. As I've noted previously in a similar thread on this forum, it is NOT the total connected load but the PERCENTAGE of load connected that requires power. The term is called the diversity factor. The nation's electrical utility grid relies on this factor 24 hrs day / 7 days week. IF the grid were required to supply 100% of the total connected load, the grid would need to be several orders of magnititude larger, which is not feasible or affordable. USUALLY only 15% - 25% of the total required power is needed. The same philosophy was adopted by the MOPAR engineers when the vehicle's systems were designed. Therefore, the balance of power needed by the vehicle for operation, is supplied by the battery, on a TEMPORARY basis.....this is perfectly acceptable. And the power withdrawn or consumed (not sucked out as vocalized by others..get the terminology correct), will be replaced when the load is reduced and normal operating conditions resume. The world will not come to an end if the battery supplies a percentage of power required for operation.....what works for the utilities will also be applicable to vehicle operation.....the diversity factor. I'm sure that this fact conflicts with your next door neighbor's, cousin's husband's sister-in-law's nephew's best buddy's friend thinks about the subject. I'm sure that others will disagree the premise.
BOB RENTON
 
I don't have answers, but questions?
Are you using the original crank / waterpump pullets and alternator brackets?
If so, then the stock style alternator needs a pulley with a stock offset to have the belts align.
I was chatting with another member who was changing from a dual v-belt to single v-belt, and the pulleys are not aligned.
If the crank damper is aftermarket, some don't have the stock thickness which also moves the pulley / belt alignment off.

Most of the aftermarket replacement alternators like Power master have both field terminal connections that can be connected to so they will work with the older 1970 and earlier style voltage regulator, or the 1971 and newer style voltage regulator.
I think original style was the round back alternator? I never used a Power master replacement, but their round back version would look period correct. Seems they are built to the same specs as the square back alternators?
Looks like the 7018 is a single pulley version and 7019 is a dual pully version?
 
I don't have answers, but questions?
Are you using the original crank / waterpump pullets and alternator brackets?
If so, then the stock style alternator needs a pulley with a stock offset to have the belts align.
I was chatting with another member who was changing from a dual v-belt to single v-belt, and the pulleys are not aligned.
If the crank damper is aftermarket, some don't have the stock thickness which also moves the pulley / belt alignment off.

Most of the aftermarket replacement alternators like Power master have both field terminal connections that can be connected to so they will work with the older 1970 and earlier style voltage regulator, or the 1971 and newer style voltage regulator.
I think original style was the round back alternator? I never used a Power master replacement, but their round back version would look period correct. Seems they are built to the same specs as the square back alternators?
Looks like the 7018 is a single pulley version and 7019 is a dual pully version?

Isn't the drive sheave on the Powermaster alternator pressed on the alternator 's rotor shaft like the origional OEM method (interference fit, no key)? The sheave is pressed on to the outboard bearing retainer regardless of wether its a single or dual groove sheave? To get the centerline of the alternator's sheave's "V" to align with the centerline of the crankshaft driving sheave "V", the alternators sheave position could be "adjusted" axially to insure that alignment is correct? I've no familiarity with the Powermaster offerings. Just asking......
BOB RENTON
 
The only Power Master alternator I have used is the one that came with the billet specialties Tru-Track system. It is a internal regulated serpentine belt system, so really can't compare to a replacement type alternator? The quality seems good. Haven't had any issues with the system except that it limits the room between the Radiator and accessory drive, so can't run a real deep cooling fan.
The remote power steering reservoir fitting seems to drip. It is just a bulkhead fitting, so should be able to tighten it. Might just tig it and not worry about it coming loose.
 
Bigger alternators to keep the batt out of the game as much as posible keeping the charging system healthier and happier with and amm reading centered. So making that the alt will provide the juice at lower RPMs than factory assembly did.

Why still deny rest of ppl experiences? After 40 years of getting Mopar bulkhead conectors burnt and STILL on relatively stock cars some must have been learnt in the practical and real world, with all the testimonials and images around, away from the theories which even MaMopar could have applied "correctly". But I guess some ppl is not able to catch that... yet, no matter how many cars will show and testify this low performance area on our cars and burnt/melted parts of the installation.

Fortunatelly my car BEING A REAL DAILY DRIVER on a 6-7 millions ppl city with daily A/C use and no extra accs more than halogen headlights upgrade and its owner ( me ) have been happy and in relative peace with the charging system performance with a higher 80 amps alt ( stock replacement from 80s, able to get around 45-48 amps at iddle... what the stock 70s alt was able to give just as full output, giving throttle )... and will be even happier and totally in peace when I jump out up to a 100 amps alt or any other rate able to give me around 60-65 amps at iddle, which is mandatory under a tropical stormy rain ( wipers on on max speed, A/C-Heater on ) at nights in a heavy traffic city ( brakes applied, sometimes geared ) to get a nice amm reading of zero or closer to zero as posible.

If some ppl want to get that happy experience and be in peace, will be welcomed, and I will still sharing how I made it, being posible without any wiring mod just some adds, keeping the stock system working as intended ( isn't this what a resto means ? keep the car working as intended per its design as much as posible ? ) with just some touch ups.

Aside this, upgrade the alt to get better electrical performance for the same reason ppl upgrade fuel systems, ignition systems, engine, brakes... Some ppl is happy with what the stock system is, some ppl is not and wish to get it better per their needs... even on new cars nowdays.

For those who doesn't drive these cars as a driver anymore, this upgrades could blown their minds as a "not needed" upgrade, but for those who still wants to drive the car daily or almost daily, some of this stuff is a need. Charging load capacity is a must on the actual streets/avenues capacity and the ammount of cars riding around. I can't imagine driving on any city downtown iddling maybe 50% of the time with a stock Mopar alt from those days anymore.... maybe back in the days was posible, but not anymore now.

Sure if you live into the country and have empty roads, driving at 1200-1500 RPMs average won't even notice EVER you really need to get more juice from your existant alt.

There is a reason why also some race cars get alts with bigger pulleys and low capacity units... less dragging from it stealling some HPs while giving output, they usually are on high RPMs and also save the bearings... and I have known some even don't run alts ( or disconect it ) along the the race... but this is not a reallity on a regular street car.

Higher capacity alts maybe weren't posible on those days without get into oversized parts ( such as the leece neville alt ) but is posible now and even more being a regular request.

Now will be nice get a RESPECT on my opinion and lived experiences... ( just a hope ).

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