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Alternator for Case 9210-9390 Agricultural Tractors - Delco 21SI 12V IR/EF

Alternator for Case 9210-9390 Agricultural Tractors - Delco 21SI 12V IR/EF

SKU:400-12182

Regular price £165.92 GBP
Regular price Sale price £165.92 GBP
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Alternator for Case 9210-9390 Agricultural Tractors - Delco 21SI 12V IR/EF

Delco 21SI alternator, 3-wire hookup, negative ground - Lester 8029N

This 12-volt alternator is built to OEM specification as a direct replacement for the Delco 21SI series unit, using an internally regulated, externally fan-cooled (IR/EF) design. The 21SI is a heavy-duty case-style alternator used on trucks, buses and industrial equipment, and is the factory-fitted charging unit on the Case 9200 and 9300 series articulated tractors with 6-504, Cummins 6-611 and Cummins 6-855 diesel engines.

It is set up for a 3-wire hookup on a negative ground system, with a 5/16 inch B+ stud and a 10-24 R-terminal, so it connects exactly like the original alternator. The unit uses six avalanche diodes and has no I-terminal connection, matching the original #438 regulator wiring configuration. The rotor is bi-directional, so it can be driven in either rotation.

Key Features

  • Direct OEM fit and function for Delco 21SI series alternators
  • 12-volt, internally regulated, externally fan-cooled (IR/EF)
  • 3-wire hookup, negative ground, bi-directional rotation
  • 5/16 inch B+ stud, 10-24 R-terminal, no I-terminal
  • Six avalanche diodes as fitted to the original unit
  • Covers Case 9210 to 9390 articulated tractors, 1990-2005
  • 12-month warranty as standard

Technical Specs

Specification Detail
Voltage 12V
Amperage 145A
Base Design Delco 21SI
Regulator Internal (IR)
Fan Type External (EF)
Rotation Bi-directional
Shaft Outside Diameter 22.2mm (0.874in)
Shaft Thread 5/8-18
Plug Clock / Plug Code 12 / 151
B+ Stud 5/16 inch
R-Terminal 10-24
Diodes 6 avalanche diodes
Weight 7.6kg (16.7lb)

Vehicle Fitment Guide

Years shown are the overall coverage span for this part. Please confirm against the OEM part number on your original unit before ordering.

Make & Model Years
Case 9210 tractor - 6-504 diesel 1990-1995
Case 9230 tractor - 6-504 diesel 1990-1995
Case 9240 tractor - 6-504 diesel 1990-1995
Case 9250 tractor - Cummins 6-611 diesel 1990-1996
Case 9260 tractor - Cummins 6-611 diesel 1990-1996
Case 9270 tractor - Cummins 6-855 diesel 1990-1999
Case 9280 tractor - Cummins 6-855 diesel 1990-1999
Case 9310 tractor - 6-504 diesel 1995-2004
Case 9330 tractor - 6-504 diesel 1995-2003
Case 9350 tractor - Cummins 6-611 diesel 1995-2004
Case 9370 tractor - Cummins 6-855 diesel 1995-2005
Case 9370QT tractor - Cummins 6-855 diesel 1995-2004
Case 9380 tractor - Cummins 6-855 diesel 1995-2004
Case 9380QT tractor - Cummins 6-855 diesel 1995-2004
Case 9390 tractor - Cummins 6-855 diesel 1995-2004

OEM Part Number Cross Reference

Aftermarket replacement. OEM part numbers are listed for reference only.

Part Number Manufacturer / Brand
1117898, 10459547, 1-2293-00DR, 240-882A Delco
1983221C1, 1987560C1, 1987560C1R International Harvester / Case
8029N Lester reference

Frequently Asked Questions

Will this fit without modification?

Yes, it is a direct replacement for the Delco 21SI series alternator, matching the original 3-wire, negative-ground hookup and mounting.

My tractor is not on the list - can I still use it?

Possibly. The 21SI was fitted to a wide range of industrial and agricultural machinery beyond the Case models listed. Compare the cross reference numbers and the terminal layout against your original unit, or contact our technical team.

What's included?

One alternator, ready to fit in place of the original unit.

How do I know my old alternator has failed?

Common signs include a charge warning light staying on, a flat or slowly discharging battery, or dimming electrical accessories at idle.

Does this have an I-terminal connection?

No, this unit does not have an I-terminal - it uses the 3-wire hookup described above, matching the original Delco 21SI wiring.

Dispatched from the UK · 12-month warranty · Fitment support from our technical team
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Shipping calculated at checkout. Free shipping over £150. Terms apply