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Old 25-01-2021, 08:37   #1
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No J10 x 2" dia Alternator Sheaves?

Why aren't J10 alternator sheaves made for 2" diameter?
I can only find 2.3" and 2.4" diameter sheaves.


Looking for such sheaves made for Delco Remy 28SI shaft 7/8" diameter with no keyway or set screw needed.
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Old 25-01-2021, 09:24   #2
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Re: No J10 x 2" dia Alternator Sheaves?

My guess is that it is because a 7/8" shaft is rather big for only a 2" pulley. The 2" pulleys I can find stop at 3/4" shafts. If it really is needed, have you got a 7/8" silver and demings and a drill press? You'd only be taking 1/16" of the walls.
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Old 25-01-2021, 17:27   #3
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Re: No J10 x 2" dia Alternator Sheaves?

@tkeithlu
That seems like a very reasonable approach to use a drill press, J20 x 2" dia sheaves are not readily available, but I have just found one J6 x 1.9" dia sheave from B&B which has a set screw for $35. Perhaps I can grind the width down to fit on the Delco Remy SI28 shaft. Then I would have to use a J6 belt instead of j10.
The crank sheave I am planning to use is J10.

That would be far less cost than the $264 I was quoted for machining a properly dimensioned J10 x 2" dia. x 7/8" shaft dia sheave, with out using a bushing.

See this J10 x 2" dia (10J200JA) Sheave $36.23 that requires a JA x 7/8" bushing $7.50 is quite reasonable but I am concerned about two things with this sheave and bushing:
  1. The Delco Remy 28SI uses a nut and heavy washer to compress the sheave to torque of 70-90 psi which will compress the tapered bushing into the outer sheave and may crack something. The spec sheet shows a Torque Capacity (lb/in) 1,750 (See page 315 for the JA bushing which shows Torque Capacity as 1750 lb/in.) So now I wonder if this bushing would work, if I can get it to fit!
  2. The thickness of the sheave needs to work with the Delco Remy 28SI shaft and and compression nut. The bushing flange is .313" and the full thickness of the bushing is 1.0". I believe that the shaft may be longer than 1" so perhaps additional washers are needed or something.
Should I just try the sheave and bearing above?
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Old 25-01-2021, 18:13   #4
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Re: No J10 x 2" dia Alternator Sheaves?

Balmar J10 x 17mm for Hitachi Alternator
2.3" dia x J10 but it does not look like it provides enough thickness for the Delco Remy 28SI shaft to allow the compression nut and washer to work.

Balmar AltMount 48-AM-102 2.4" Diameter, 17mm Bore
Has a similar problem.

Balmar 48-AM-39 J10 for 95-Series 2.7" Diameter, 0.875" Bore (7/8")
This one would fit without boring, but it is 2.7" dia.

Balmar installation docs "The AltMount alternator pulley can be used on any alternator with a 17 mm rotor shaft. "
Mainesail wrote:
"Most of the small case Delco based alts are 17mm. This does not mean the offsets are the same, so some machining or alignment or spacers etc. may still be necessary. Balmar's old 91 series, also a 10DN frame, used a "dished fan" and the 10 groove pulleys still fit the old Balmar 91/10DN frame with very minimal to no fuss. The Amptech, depending upon year, may or may not use a dished fan. Most are a flat fan with a spacer behind it. The nub on the back of the E-Maax or AltMount pulley may need to be machined off and it is pretty difficult to tell until you have the pulley in hand..."
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Old 26-01-2021, 14:32   #5
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Re: No J10 x 2" dia Alternator Sheaves?

The sales engineer confirmed that compressing this bushing with 90 psi torque will be okay because it is a steel bushing. J10 x 2" dia (10J200JA) Sheave $36.23 with JA x 7/8" bushing $7.50

This bushing and sheave is 1" in width, yet the Delco Remy shaft is closer to 1.31" in length (from Delco Remy drawings) before the threads start.
As a consequence I will need to find some well machined thick washers totaling 0.31" with a 7/8" hole.

I am still not certain if this will work properly, but it worth trying it.
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