[lateapex911]

OK, the issue: New alternator nut from Pelican...Porsche, part #: 90160390501 doesn't fit. It is listed on the site as 16 x1mm

My alternator (from originally a 1973 911E is, I believe, a Motorola. I *think* I had it rebuilt in 1996 in Glendale CA...and it has a brown rectangle inset in the upper part, with a tab marked DF, and 5 bolts arrayed from 9 o'clock to 3. The bottom 3 are on a raised semi circle that's red (has fins on the back (interior to the alt) side. it's marked "D+/61" at the 8 o'clock position and "B+" at the 6 o'clock position. On the alt body, the bolt at 9 has no markings the one at 3 says "D"

And the shaft....is: (Outside diam) 15.9mm x 1mm thread pitch as measured. The inside (deep part) of the thread is 15.54mm.

I describe all that as it might be a clue to somebody who knows old alts!

So, the Porsche nut bag matches the art number ordered. But the nut won't thread on. It measures 14.92mm inside diameter. (I can't measure into the threads) But the thread npitch is correct at 1mm. The face to face of the exterior is 21.98mm, which is odd because the web lists all 16mm nuts as 24mm face to face (where the wrench goes). Which might be a custom Porsche thing,? It's 8.02mm thick.

So, the matching numbers (to my mind) should be the inside nut diameter and the deepest part of the thread diameter of the shaft. Seems to me the nut has to be a tad bigger than the shafts deepest diameter. But I'm the opposite: Shaft minimum is 15.54mm. the nut minimum is 14.92mm.... nut needs to grow by .62mm

Whats going on???


More random info...my not exhaustive digging shows this is the largest of alternator shafts, others are 14mm

What to do??

Sadly I don't happen to have a 16mm x 1 thread tap.
is this just a plating build up Seems like thats a LOT.

Or am I some idiot here?

(I lost the OE one after getting it plated ...the tensioning washer too! Arrrg. )

What say the Pelican experts??