Mid year Alternator Diode Stampings

[John L.]

Could someone please describe the red and black stampings on the diodes of a mid-year alternator. I know what is stamped, however what size are the characters and are the three rows of charaters directly over each other ?? Does someone sell a stamp ?? Can I have one made up ??

thanks -- john lolli

[Robert B.]

Re: Mid year Alternator Diode Stampings

Call Mr John Pirkle. u will find his ad in the Driveline

[Robert B.]

Re: Mid year Alternator Diode Stampings

Call Mr John Pirkle. u will find his ad in the Driveline

[Jack H.]

Re: Mid year Alternator Diode Stampings

I think you'll find this (number/sequence) defined in your copy of the applicable Judging Guide. Don't got one? We sell 'em--visit the STORE on this web site.

As far as available stamps to do it yourself, there are none (at least the last I checked). Two problems:

(1) What are we duplicating?
(2) How to handle the variable portion of the stamp that represents date?

Several of the professional alternator restoration sources offer a step up in authenticity to 'correct' dated diodes. BUT, there were a SLEW of qualified vendors back then and diode supply was taxed to the limits of production....

GM's Delcotron hit the market in '63 (a full three years after Chrysler's first product and patent position in the '60 era). Apparently Ford and GM decided not to take a license to Chrysler's patent (lowest cost 4-diode full wave bridge circuit topology) and used a 3-phase, 6-diode bridge technology. Soooo, the Big Two join the last of the Big Three in gobbling up diodes only their designs are 'hogs' eating an additional two diodes/alternator where/when unnecessary. The fledgling semiconductor industry is on its knees trying to meet demand. We're only 10-years or so out from the first commercial production of the transistor at this point.

The 'marks' seen on the back side of diodes were put there by the suppliers to GM and font, spacing, mfgr logo, Etc. is left to the individual supplier. So, that dude who's going to give you a 'concours correct' stamp, who's pattern does he copy?

Heck, I've so many 'correct' restored alternators come out of a shop in Georgia wearing Motorola brand fresh ink I could almost scream. Having stalked the scrap yards and picked through alt bins for years I can pretty much assure you, the Motorola brand was in a reasonable minority back then.... But, the benefit of the doubt goes to the owner and the 'restoration' passes for correct.

If I were you, I wouldn't screw around with trying to make up stamps or pay some service to give you 'correct' reproduction diodes. I'd simply go to my local scrap yard, find ANY untouched Delcotron from my time period (the diodes were the SAME, only the pulley, field windings and rotor changed), pay the whooping $5 core charge for it, take it home and press out and re-use the real McCoy absolutely/positively correct factory original diodes (AFTER I put 'em up on a curve checker to make sure there was no junction puncture residual damage).

But, then I get acquised of being 'wierd' so take what I say for what it's worth.... Personally, I'd rather see the real McCoy items than the same old 'restoration' pieces. They varied all over the place like a rainbow in terms of font, marking, placement....

[Jack H.]

Re: Mid year Alternator Diode Stampings

I think you'll find this (number/sequence) defined in your copy of the applicable Judging Guide. Don't got one? We sell 'em--visit the STORE on this web site.

As far as available stamps to do it yourself, there are none (at least the last I checked). Two problems:

(1) What are we duplicating?
(2) How to handle the variable portion of the stamp that represents date?

Several of the professional alternator restoration sources offer a step up in authenticity to 'correct' dated diodes. BUT, there were a SLEW of qualified vendors back then and diode supply was taxed to the limits of production....

GM's Delcotron hit the market in '63 (a full three years after Chrysler's first product and patent position in the '60 era). Apparently Ford and GM decided not to take a license to Chrysler's patent (lowest cost 4-diode full wave bridge circuit topology) and used a 3-phase, 6-diode bridge technology. Soooo, the Big Two join the last of the Big Three in gobbling up diodes only their designs are 'hogs' eating an additional two diodes/alternator where/when unnecessary. The fledgling semiconductor industry is on its knees trying to meet demand. We're only 10-years or so out from the first commercial production of the transistor at this point.

The 'marks' seen on the back side of diodes were put there by the suppliers to GM and font, spacing, mfgr logo, Etc. is left to the individual supplier. So, that dude who's going to give you a 'concours correct' stamp, who's pattern does he copy?

Heck, I've so many 'correct' restored alternators come out of a shop in Georgia wearing Motorola brand fresh ink I could almost scream. Having stalked the scrap yards and picked through alt bins for years I can pretty much assure you, the Motorola brand was in a reasonable minority back then.... But, the benefit of the doubt goes to the owner and the 'restoration' passes for correct.

If I were you, I wouldn't screw around with trying to make up stamps or pay some service to give you 'correct' reproduction diodes. I'd simply go to my local scrap yard, find ANY untouched Delcotron from my time period (the diodes were the SAME, only the pulley, field windings and rotor changed), pay the whooping $5 core charge for it, take it home and press out and re-use the real McCoy absolutely/positively correct factory original diodes (AFTER I put 'em up on a curve checker to make sure there was no junction puncture residual damage).

But, then I get acquised of being 'wierd' so take what I say for what it's worth.... Personally, I'd rather see the real McCoy items than the same old 'restoration' pieces. They varied all over the place like a rainbow in terms of font, marking, placement....

[John L.]

Re: Mid year Alternator Diode Stampings

Jack

Thanks for the response. I am just trying to up the score a few points from the last time the car was judged (10/14/2001). In addition to the diodes not being stamped, I am also looking for the infamous plastic clip that attaches the harness to the alternator. I have been looking through scrapyards in Southern NJ as you suggest, however, I have not been lucky enough to find one as yet. Hence the questions.

thanks again
john lolli

[John L.]

Re: Mid year Alternator Diode Stampings

Jack

Thanks for the response. I am just trying to up the score a few points from the last time the car was judged (10/14/2001). In addition to the diodes not being stamped, I am also looking for the infamous plastic clip that attaches the harness to the alternator. I have been looking through scrapyards in Southern NJ as you suggest, however, I have not been lucky enough to find one as yet. Hence the questions.

thanks again
john lolli