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[Jim G]

Hi all
Finally gotten around to swapping my generator for a GM 10SI type alternator.
Question - should I try to use both "ears" of the standard generator bracket to mount the alternator? I was planning on using a long bolt through both ears and the alternator mounting lug.
Seems like the holes are offset a bit such that the alternator pulley is at a slight angle to the other pulleys.
I'm wondering if it'd be ok to mount the alternator just on the front ear of the bracket although obviously won’t be as stable.
Any advice gratefully received!
Thanks.

Jim - 64 TR4

[TR3driver]

I don't believe it is acceptable, Jim.  I tried it on my TR3A, and while it did seem to work, the belt life seemed oddly short and the bolts kept working loose.  I believe that at certain engine rpm, the mounts were flexing enough to cause problems.

I drilled the rear hole out to the same diameter as the front hole, and used a long bolt, plus a piece of pipe as a spacer between the original mount ears.  After that mod, all the problems disappeared.  There did appear to be a very slight angle, but it did not seem cause problems.  After making the change, I think I changed the belt once in some 10 years and perhaps 100,000 miles.

But that was a Motorcraft alternator, not a 10Si.

[Bob Muzio]

Randall, I used a Delco and did approximately the same operation with along bolt and a spacer.
Bob

[Jim G]

Thanks guys - I was wary of only using one ear and you've confirmed it for me.
There doesn't appear to be a difference in hole diameter on my 4 between back and front of the bracket but definitely an angle there, albeit fairly slight. I think its enough to cause wear though so I need to find a way to align it.

[TR3driver]

There doesn't appear to be a difference in hole diameter on my 4 between back and front of the bracket

That is strange, since the TR4 mount is the same as the TR3 (Stanpart 58912).  And according to the TR4 parts catalog, the pedestal takes a 1/2" nut while the rear bolt takes a 5/16" nut.  Sounds like perhaps your bracket has already been modified, or else the rear hole is damaged from being loose.  That might explain the angle as well.

[Jim G]

Hmmm...thanks Randall. I double-checked and I can only think I had a brain-fart when I looked at this first time round. The holes ARE indeed different sizes...
So I think my initial dry run at lining up the alternator allowed me to get that angle when I didn't line the long bolt up in the center of the front bracket hole.
If I find a suitable bushing for the front hole, I think I'll be in good shape.
Hopefully...
Thanks again...must get a parts book...

[TR3driver]

...must get a parts book...

Shhh, don't tell anyone ... https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B2H2NJt34OffYjZmY2ZlYzctYzg5OC00OTc4LWE3MmEtMmRiODI3OTliY2Y4&hl=en

[Jim G]

Thnaks! Tell me, how did you tell the difference in nut size from that document?

[TR3driver]

Ah, for that you need the magic decoder ring:
https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B2H2NJt34OffMjJhY2YwZmQtYzgxNC00ZTk0LTk1YTUtZTIyZmU3ZTc1Y2M4&hl=en

[Jim G]

that would be it - thanks