67S alternator question

gmiles · 01-08-2005, 12:57 PM

yes I did a search, but didn't find my answer. I have a 67S and smoked the alternator (I saw the smoke!). I bought a reman Bosch witch is what it had. There were some differences I noticed when I pulled the new one out of the box. 1) the pulley nut is larger 22mm up to 24 mm I think. 2) there were 2 spade connectors on the back of my old one marked DF and D-. The new one has one spade conn. marked DF and a nut marked D-.

Both of the spade conn. on my old one were next to each other on a removable piece.

Both are 55A externally regulated. Im I good to go with the new alternator?

Lorenfb · 01-08-2005, 04:13 PM

You got the less reliable & later unit for a replacement, i.e. a Marchel/Motorola.
The original Bosch alt. is a much more reliable alt. This replacement requires
having a lower battery voltage, i.e. 13.8 (max) versus 14.0-14.3 with the Bosch.

gmiles · 01-08-2005, 04:53 PM

This is what I got.

Lorenfb · 01-08-2005, 07:33 PM

That looks like the later 70 amp Marchel which will stick-out too far for the fan pulley.
Compare the measurements of each alternator, the old & new. You may need
a new fan housing, not cheap.

Evans, Marv · 01-08-2005, 07:37 PM

Can't you see if you can get your old one rebuilt??

gmiles · 01-08-2005, 08:23 PM

I measured the shaft length and diameter, then thought I should post before I put the whole thing together. Tryin' to avoid mistakes!! I talked to a rep from the place I bought the alternator from (ordered online since Pelican shows NLA). I was assured it was a 55 amp externally regulated alternator and that it was a Bosch unit. I ordered a new voltage regulator,too. I'll have to measure the housing length. The core charge was $20, so maybe I'll keep my old alternator?

Lorenfb · 10:34 AM

"I measured the shaft length and diameter,"

That's not the critical measurement. It's from the back flange to the front shaft spacer.

It's not a 55 amp. It's a 70 amp. You can tell by the stator. Also, a Bosch USA agent
rebuilt the Marchel unit. It's NOT a Bosch. Bosch made neither the 55A nor the 70A alternator.
Bosch was not a 911 alternator supplier until 1989 on the 964 engine.

gmiles · 01-09-2005, 07:29 PM

Yup, I measured the reman alt. and it's 3/8 of an inch longer. I'll have to send the reman back. I searched and found local numbers from reputable shops to get my old one rebuilt.

As far as Bosch not suppying early 911's with alternators, where did they come from? My old alt has a metal Bosch name plate on it like my dist. The metal plate had the following info:

K1-14V 55A 20
LJ 328/23 S14

On the housing was stamped 1125824125

thnx for all the help

Lorenfb · 01-10-2005, 05:06 AM

"As far as Bosch not suppying early 911's with alternators, where did they come from? My old alt has a metal Bosch name plate on it like my dist."

Sorry, the first few years of the 911 had Bosch alternators until the early '70s,
then Porsche switched to Marchel/Motorola. As I said before, Porsche didn't
start using Bosch again until '89 in the 964.

gmiles · 01-10-2005, 09:28 PM

ok, thanks for the help, Loren. I owe you a beer at Mcormick & Schmidts!!!

Lorenfb · 01-11-2005, 07:18 AM

"ok, thanks for the help, Loren."

You wise to get the original one rebuilt.
Hopefully, you'll get a good rebuilt unit. Most rebuilders do ?? job.