Mopar Muscle - - Contents - TEXT AND PHO­TOS: CHRIS HOL­LEY

Charg­ing sys­tem up­grade with a Tuff Stuff Al­ter­na­tor

From the early 1960s through 1974, Chrysler pro­vided the buy­ing pub­lic with a hardy, re­li­able, low-amp charg­ing sys­tem that required min­i­mal upkeep. The pre-1970 Mopars were equipped with a low-main­te­nance ad­justable ana­log volt­age reg­u­la­tor, but with the pro­gres­sion from a breaker-point to a breaker-less ig­ni­tion, Chrysler in­tro­duced a tran­sis­tor­ized volt­age reg­u­la­tor, which pro­vided bet­ter volt­age spike pro­tec­tion than an ana­log reg­u­la­tor for the newly in­tro­duced elec­tronic ig­ni­tion mod­ule. A prob­lem with the early Chrysler charg­ing sys­tems oc­curred when an elec­tric fuel pump, an elec­tric fan, an af­ter­mar­ket ig­ni­tion, or a slew of other elec­tri­cal com­po­nents started be­ing added to the ve­hi­cle. The fac­tory 35-amp, 46-amp, or even 60-amp al­ter­na­tor may not have the ca­pac­ity to main­tain the ve­hi­cle’s charg­ing sys­tem ef­fec­tively un­der all elec­tri­cal load con­di­tions. In an at­tempt to rem­edy the concern, one could swap a 1975-or-later 100-amp Chrysler al­ter­na­tor into the low-amp al­ter­na­tor’s brack­ets on the en­gine, but then the fac­tory am­me­ter, bulk­head, and charg­ing sys­tem wiring could fail with the in­creased am­per­age. In an at­tempt to re­duce the am­per­age through the bulk­head, a mid-1975 (or newer) shunted am­me­ter could ac­com­pany the 100-amp al­ter­na­tor, re­duc­ing the am­per­age through the bulk­head. While these mods could work, was there some­thing bet­ter? We con­tacted Tuff Stuff Per­for­mance Ac­ces­sories of Cleve­land, Ohio, and ar­ranged to test one of their Usa-built, 130-amp, 1-wire alternators in their new Cast Plus+ fin­ish on our test ve­hi­cle, a ’69 Dodge Dart.

Our Dart is equipped with a warme­dover 340 that stirs a re­verse-man­ual rowed Torque­flite 904 that feeds a 4.10-geared 8¾-inch rear end. At this point in its life, the Dart is al­most ex­clu­sively uti­lized as a pump-gas, low 11-sec­ond, multi-time track cham­pion drag car. Although, with the re­con­nec­tion of the brake light switch, re­in­stal­la­tion of a belt and belt-driven wa­ter pump pul­ley, and bolt­ing on some Do­tap­proved tires, the Dart could be legally driven on the street. The au­thor has owned the Dart since the sum­mer of 1989, and over the years, var­i­ous elec­tri­cal com­po­nents have been added. With each ad­di­tion, not only has the au­thor’s sup­ple­men­tary years of ex­pe­ri­ence pro­vided a bet­ter and cleaner tech­nique of in­stal­la­tion, but the ad­di­tional elec­tri­cal de­mands on the charg­ing sys­tem have also in­creased. Some elec­tri­cal in­stal­la­tions oc­curred al­most 30 years ago, and while they were com­pe­tent in­stal­la­tions, the up­grade of the new Tuff Stuff al­ter­na­tor will pro­vide us with an op­por­tu­nity to do some mod­ern­iz­ing of our charg­ing sys­tem and aged elec­tri­cal wiring.

As the Dart be­came more bracket racing ori­ented, a Hol­ley elec­tric fuel pump was added, and then a pair of Moroso fans (a pusher and a puller) was added in con­junc­tion with a Moroso elec­tric wa­ter pump drive. These four com­po­nents in­creased the con­stant elec­tri­cal de­mand by 32 amps (fuel pump 8 amps, wa­ter pump 9 amps, and the elec­tric fans 15 amps) with even more am­per­age de­mand upon ini­tial startup of each com­po­nent. The fac­tory rated 35-amp al­ter­na­tor couldn’t meet the charg­ing sys­tem’s elec­tri­cal de­mand with these ad­di­tional loads. With the Dart be­ing ded­i­cated to drag racing, the in­creased elec­tri­cal de­mand shouldn’t have been a big deal — just hook up a bat­tery charger be­tween rounds to main­tain the bat­tery’s charge. How­ever, in the late rounds, many tracks in an ef­fort to beat cur­few will run the cars in a round robin af­fair, so charg­ing the bat­tery is no longer an op­tion. It’s not un­com­mon for the Dart to make a se­ries of two, three, or even four runs in a row with­out an op­por­tu­nity to charge the bat­tery, and due to the lack of proper charg­ing, the ig­ni­tion per­for­mance could drop off re­sult­ing in less con­sis­tent elapsed times. This sit­u­a­tion is ex­ac­er­bated when you’re go­ing rounds and run­ning two classes.

In the 1990s, the so­lu­tion for the charg­ing prob­lem was to sig­nif­i­cantly en­hance the fac­tory wiring and to in­stall a 120-amp Nip­pen­denso al­ter­na­tor from a 1991 Cum­mins Turbo diesel in place of the fac­tory al­ter­na­tor. The fac­tory brack­ets were used but the belt ten­sion ad­juster bracket was flat­tened and flipped to al­low the al­ter­na­tor to fit. One field wire was sup­plied volt­age from the volt­age reg­u­la­tor and the other field was grounded to the case. An ad­di­tional charge wire was run from the al­ter­na­tor to the B+ ter­mi­nal on the starter re­lay and then to the B+ ter­mi­nal of the bat­tery lo­cated in the trunk. Ad­di­tion­ally, the am­me­ter ter­mi­nals on the back of the in­stru­ment clus­ter were linked to­gether with a jumper wire, even though a ma­jor­ity of the cur­rent now by­passed the am­me­ter due to the di­rect wiring of the al­ter­na­tor to the bat­tery. With all of the fac­tory and af­ter­mar­ket elec­tri­cal loads mea­sured, the Dart had a 71-amp load on the charg­ing sys­tem that the Nip­pen­denso al­ter­na­tor

han­dled ad­mirably for over 20 years, but now with newer Tuff Stuff tech­nol­ogy and a more sim­plis­tic one-wire de­sign, we be­gan the up­dat­ing of our charg­ing sys­tem.

The Tuff Stuff al­ter­na­tor in­stal­la­tion would’ve been a straight­for­ward af­fair if our cur­rent al­ter­na­tor had been a fac­tory al­ter­na­tor, and the cylin­der heads were fac­tory cast units. We would’ve slipped out the old al­ter­na­tor and re­placed it with the Tuff Stuff al­ter­na­tor, but since we had the Nip­pen­denso al­ter­na­tor, we had to re­in­stall the fac­tory brack­ets be­fore we could in­stall the Tuff Stuff al­ter­na­tor. We elected to pur­chase all-new brack­ets to ease the in­stal­la­tion process. Tuff Stuff pro­vided instruction to run a charge wire from the B+ ter­mi­nal of the al­ter­na­tor to the B+ ter­mi­nal at the bat­tery, or for a hid­den look, run the wire to the B+ starter ter­mi­nal. We elected to run a 1-gauge (Amer­i­can Wire Gauge) wire from the al­ter­na­tor to the B+ ter­mi­nal of the starter tak­ing care to route the wire clear of any mov­ing com­po­nents and the head­ers. The B+ ter­mi­nal of the starter was the point to which the cur­rent flowed to the bat­tery and to the newly in­stalled elec­tri­cal power junc­tion point of the Dart. We in­stalled a 150-amp ANL fuse be­tween the al­ter­na­tor and the B+ starter ter­mi­nal to iso­late the al­ter­na­tor from the rest of the charg­ing sys­tem in case of an al­ter­na­tor short.

Years ago, when the bat­tery was moved to the trunk, we added 0-gauge wire that ran from the B+ starter ter­mi­nal to the master cut­off switch lo­cated in the trunk. From the master cut­off switch, a short 0-gauge wire ran to the B+ ter­mi­nal of the bat­tery. Also, from the B+ starter ter­mi­nal, we ran a pair of 10-gauge wires to our newly in­stalled junc­tion point. The junc­tion point pow­ered up pre­vi­ously in­stalled com­po­nents (aux­il­iary fuse box, B+ starter re­lay, and backup starter re­lay) as well as a newly added am­me­ter by­pass wire.

We fi­nally ad­dressed the Achilles’ heel of a clas­sic Mopar’s charg­ing sys­tem: the am­me­ter. With a jumper wire, we had con­nected the ter­mi­nals of the am­me­ter to­gether, but as we found dur­ing our prepa­ra­tion to test the Tuff Stuff al­ter­na­tor, dam­age to the bulk­head con­nec­tor had al­ready oc­curred. At some point in the last 49 years, the con­nec­tor ter­mi­nals be­came cor­roded caus­ing an over­heat­ing con­di­tion, which melted our bulk­head con­nec­tor at pins J and P. To fix this am­me­ter prob­lem per­ma­nently, we re­moved the male ter­mi­nals J and P from the bulk­head con­nec­tor. We ran a 14-gauge fusible link 10-gauge wire from the junc­tion point in the en­gine bay to the in­stru­ment clus­ter. We re­moved the two wires from the am­me­ter ter­mi­nals and bolted the fused 10-gauge wire and the two am­me­ter wires to­gether. Ty­ing these three wires to­gether pro­vided cur­rent flow to the var­i­ous fac­tory com­po­nents that uti­lized the am­me­ter wires un­der the dash. This mod­i­fi­ca­tion greatly in­creased the qual­ity of the charg­ing sys­tem, the am­me­ter is com­pletely dis­con­nected from the charg­ing sys­tem, and the ter­mi­nals at the bulk­head will no longer cause a prob­lem. In the fu­ture, we could add a volt­meter in place of the am­me­ter, and all that would be required is tap­ping into one of the orig­i­nal am­me­ter wires for the B+ and pro­vide a ground for the volt­meter to be op­er­a­tional.

With all of our prep work com­pleted, we in­stalled the Tuff Stuff 1-wire al­ter­na­tor into the fac­tory brack­ets. With some spac­ing ad­just­ments due to the af­ter­mar­ket heads, the al­ter­na­tor fit per­fectly. We at­tached the 12-volt charg­ing wire from the 150-amp ANL fuse to the B+ ter­mi­nal on the back of the al­ter­na­tor. With ev­ery­thing se­cured, we turned the ig­ni­tion key, and the en­gine roared to life. The charg­ing sys­tem volt­age was mea­sured at idle at the B+ ter­mi­nal on the al­ter­na­tor, and it was in­stan­ta­neously above 14.5 volts (max­i­mum read­ing of 14.65 volts). There was no need to blip the throt­tle to get the al­ter­na­tor to charge. At

2,000 rpm, the volt­age re­mained above 14.5 volts (max­i­mum of 14.67 volts). We checked the volt­age drop be­tween the al­ter­na­tor and the B+ starter ter­mi­nal, the volt­age drop be­tween the B+ starter ter­mi­nal and the bat­tery, and the volt­age drop be­tween the B+ starter ter­mi­nal and our newly in­stalled junc­tion point, and we found less than .1-volt drop through­out the charg­ing sys­tem.

The Tuff Stuff al­ter­na­tor in­stalled with ease, fit prop­erly, and pro­vided a steady volt­age and am­ple cur­rent to meet our drag racing late-round re­quire­ments. If the ve­hi­cle has a master cut­off switch like our Dart does, there needs to be a way to drop the field when the master cut­off switch is pushed to the “off” po­si­tion. We cover this in the ac­com­pa­ny­ing pho­tos. Fol­low the steps to fin­ish the in­stal­la­tion, and if there isn’t a master cut­off switch on your ve­hi­cle, just in­stall the Tuff Stuff al­ter­na­tor, run a B+ wire to the bat­tery, and enjoy the trou­ble-free charg­ing sys­tem on your Mopar.

Tuff Stuff alternators are avail­able in a wide range of fin­ishes in­clud­ing chrome plated, pol­ished alu­minum, black chrome, stealth black, as cast, or the new Cast Plus+. The alternators are avail­able in 1-wire or OEM plug-in style in 60-amp, 100-amp, or 130-amp out­puts. All Tuff Stuff alternators are built in the USA and have a one-year limited war­ranty. We se­lected a 1-wire, 130-amp al­ter­na­tor in the Cast Plus+ fin­ish for our ’69 Dart.

Tuff Stuff doesn’t want the al­ter­na­tor rpm to ex­ceed 18,000 rpm. At the dragstrip, the Dart’s 340 runs through the traps be­tween 6,600 and 6,800 rpm. An un­der­drive crankshaft pul­ley was added in the 1990s to min­i­mize the al­ter­na­tor rpm at high en­gine rpm. The ra­tio be­tween the Tuff Stuff al­ter­na­tor pul­ley and the crankshaft pul­ley is 1.7:1, so we’re well be­low their rpm lim­its. For in­for­ma­tion about the pul­ley ra­tios and other data, click on their In­struc­tions and Di­men­sions tab on their web­site.

The B+ starter re­lay ter­mi­nal had become a source for bat­tery volt­age for the many com­po­nents that had been added to the Dart. While this has worked for al­most 30 years, with the up­grade to the Tuff Stuff al­ter­na­tor, we planned to reengi­neer our ex­ist­ing wiring to a more man­age­able de­sign.

In the 1990s, due to the high elec­tri­cal de­mands on our Dart’s charg­ing sys­tem, we in­stalled a 120-amp Nip­pen­denso al­ter­na­tor. To in­stall this al­ter­na­tor, we had to mod­ify the mount­ing brack­ets, but we were able to re­tain the fac­tory field wind­ing con­trol with a fac­tory re­place­ment volt­age reg­u­la­tor. We ran a charge wire from the al­ter­na­tor straight to the trunk-mounted bat­tery.

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