G-Drive Engines: Choosing the Right Genset Engine
If you build, rebuild or repower generator sets, the engine is the decision everything else follows. G-Drive engines are diesel engines built specifically to drive an alternator at a fixed speed rather than to move a vehicle, and picking the right one is mostly about matching prime output to the load you actually run. We stock G-Drive engines from 20kVA up to 250kVA.
What makes G-Drive engines different
A road-going diesel spends its life changing speed. A genset engine does the opposite: it holds a constant 1500rpm so the alternator produces a steady 50Hz. That means different governing, different cooling assumptions and a duty rating quoted in kVA rather than kilowatts at the flywheel. It is also why speed controllers and governors matter so much on a genset — something we touch on in our guide to the best automated generator setup.
The three ranges we carry
Our G-Drive engine range covers three manufacturers, each strongest in a different band:
FAWDE covers the small end, where a compact four-cylinder is enough. Lovol sits in the middle with the Perkins-licensed 1000 series — the 1004TG at 74kVA, the 1006TG2A at 100kVA and the 1006TAG at 132kVA. Deutz spans the widest range, from a 30kVA BFM3-G2 up to the 250kVA TCD8.0.
Sizing: prime output, not peak
Prime output is the rating an engine will hold continuously with a varying load. Standby ratings look bigger on paper but assume limited hours. Two rules settle most of the arguments:
- Add up the running load first, then allow for motor starting surges — pumps and compressors can pull several times their running current for a second or two.
- Leave headroom of roughly 20–25%. An engine loafing at 70% load lives far longer than one held at 95%.
- Undersizing is expensive, but so is chronic light loading, which glazes bores and causes wet stacking.
What goes around the engine
An engine is only half a genset. You still need an alternator matched to it, an AVR to hold voltage steady — see what an AVR actually does — and a genset controller to start, monitor and protect the set. Add sensor alarms for oil pressure and temperature so a fault shuts the set down before it becomes a rebuild.
Spares availability is part of the choice
Buy an engine nobody supports and the first failure becomes a long wait. All three ranges we sell are backed by our diesel engine spares catalogue — bearings, gaskets, pistons, pumps and filters held locally. Keeping to the service schedule in our guide to a healthy generator matters more than the badge on the rocker cover.
If the set is backup for load shedding rather than a prime-power machine, our piece on the benefits of a backup generator is a good place to start before you spend on engine capacity you will not use.
Not sure which prime output fits your load? Send us the connected equipment list and we will size it. Browse G-Drive engines or contact our team for a quote.