There is no "correct" alternator for a Series 2A that was not fitted with a Lucas ACR 11 as an option at the factory (they have voltmeters on the dash). There are alternators that are suitable in terms of current and voltage, and that fit, and there are alternators that are not, or don't (e.g. alternators suitable for Defender 2.5 and 200 TDI engines would be suitable if they didn't foul the engine mount on a Series petrol engine..).
My late 2A has a 2.25 petrol engine, suffix A. I have fit an alternator that is "correct" for S3 vehicles starting from engine suffix B. I replaced the dynamo bracket with the S3 alternator bracket, that fits in its place, and I also swapped my S2 dynamo tensioner for a S3 alternator tensioner, which is slightly narrower and shorter, and I felt cleared the alternator blades a little better. Other than that, a 1075mm x 10mm wide x 8mm deep fan belt fits perfectly, giving good clearance between the tensioner and alternator blades, and alternator casing and engine mount. I'm really happy with the fit.
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| S2 dynamo tensioner alongside an S3 alternator tensioner |
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| Use spacers (washers) to align the belt with the cam and crank pulleys |
Alternator:
https://bearmach.com/alternator-suitable-for-series-iii-suffix-b-engine-range-rover-classic-v8-carb-vehicles-br-3551
Drive belt:
https://simplybearings.co.uk/shop/p20079562/AVX10x1075-Major-Brand-AVX-Section-Cogged-V-Belt/product_info.html
The drive belt specified in the S3 parts book is 1050mm in length. If you are fitting an alternator to a late 2A don't be surprised if you need a slightly longer drive belt. Whether the cam or crank pulleys changed diameter, or there's another slight difference in the blocks between A and B, I don't know. I needed another 25mm.
There is no "correct" alternator for a 2A with no voltmeter on the dash from the factory. You just have to find one that is suitable, that fits, and that can be aligned.
