Genset overhaul · Industrial Area 15, Sharjah
Diesel generator & genset overhaul
Strip, measure against the manufacturer's limits, machine what can be saved. The crankshaft, block and head go across the yard, not out to a subcontractor.
Which one you need
Top overhaul or major overhaul
Two different jobs, frequently quoted as if they were the same one.
The lighter option
Top overhaul
- Head, injectors, valve train and turbocharger off — pistons and liners on some families
- Triggered by lost compression, valve and seat wear, high exhaust temperature, smoke, head gasket failure
- Machining: head surfacing, seat cutting, guides, crack testing
- Restores combustion sealing and breathing — nothing below the head gasket
The full rebuild
Major overhaul
- Complete strip — head, pistons, liners, crankshaft, bearings, camshaft, pumps, cooling
- Triggered by low oil pressure at temperature, heavy blow-by, oil consumption, bearing knock, scored bores
- Machining: all of the above plus crankshaft grinding, line boring, decking, bore honing, rod resizing
- Restores the whole engine to the manufacturer's clearances
- The alternator end stays a separate job
Overhaul points vary by engine family and duty, and how the set was run matters more than the hour meter — a prime-rated set worked hard and serviced properly can outlast a neglected standby set. Send the engine model and we point you at the interval in its own manual. The measurements then decide whether that interval is telling the truth about your set.
Why the quotes differ
Ours go across the yard
When a competitor quotes a genset overhaul, the crankshaft goes to a machine shop, the head goes to a machine shop and the block goes to a machine shop. Each is a margin, a delay and a tolerance they do not control.
We machine it here. Repair stays on the table where others have to quote a replacement engine, and the date we give after strip-down holds — the only variable outside this building is parts lead time, and we name that separately.
- Measured, then quoted
Repairability turns on journal diameter, ovality, taper, hardness, bore wear and deck flatness — numbers, taken with the engine stripped.
- One schedule
No third-party machine shop queue sitting invisibly inside your lead time.
- One record
Before and after figures, crack test results, and every part fitted listed by number.
In order
What an overhaul actually involves
Nothing is committed to a rebuild until the measurements are in front of both of us.
- Two-stage quotationOne quote to strip, clean, crack test and measure. A second for the rebuild, once the components have been read. A fixed price before strip-down is either padded or about to become a variation order.
- Set down and stripIsolated, worked on site or recovered to the workshop, stripped with every component tagged.
- Clean and crack testBlock, head and rotating components cleaned, then crack tested. A cracked head found here saves the whole rebuild.
- Measure everything, and write it downBore diameter, taper and ovality; journal and crankpin sizes; bearing clearance; end float and run-out; rod bore and bend; head thickness and flatness; valve, seat and guide wear; liner protrusion — each against the service limit.
- Machining, in our own shopCrankshaft grinding, polishing and straightening; block line boring and deck surfacing; bore boring and honing to the correct crosshatch; head surfacing, seat cutting and guides; rod boring and resizing; press and lathe work as the job needs.
- Fuel injection equipmentInjectors and the pump are calibrated on the bench rather than refitted on hope — see fuel systems and calibration. A rebuilt engine fed by worn injectors washes its bores.
- Turbocharger and coolingTurbo inspected and overhauled or replaced; radiator cleaned or re-cored, water pump, thermostat, hoses and belts renewed.
- The alternator endInsulation resistance tested and the excitation chain checked, and any work done at the same time — see alternator repair and rewinding. Rebuilding around a marginal winding is how a completed overhaul comes back three months later.
- Reassembly to specificationBearing clearances set, fasteners torqued and angle-tightened to the manufacturer's figures, valve clearances set, timing verified.
- Test run, load test, returnRunning-in, then a staged profile on a load bank with readings at every step. Then install, commission and a follow-up service at the running-in interval.
Deliverables
What comes back with the set
The measurement sheet
Every dimension taken, before and after machining, against the manufacturer's service limit. Plus the crack test results.
The parts record
Every component replaced, listed with part numbers, and the fuel injection equipment test results.
The load test report
The proving run: readings at each step, showing the rebuilt set carries its rating and holds voltage and frequency.
Cover, in writing
An overhaul is not covered on the same terms as a routine repair. What applies to yours is written on your quotation and repeated on the invoice — ask for it before you accept, from us and from anyone else quoting.
You get a date once the engine has been stripped and measured, and you are told promptly if what is found changes it. Where a site cannot be without standby power, plan the sequence rather than the date — cover arranged, set out, overhaul, set back, load test, cover released. Raise it at quotation stage and it is sequenced around your shutdown windows, not against them.
Overhaul or replace the set
Buying new is a capital decision with a lead time and a commissioning cost attached. Rebuilding is an operating cost on a machine whose installation, cabling, exhaust and foundation already exist and are already approved. Which applies to your set is a measurement, not an opinion — journal diameter against the bottom undersize, ovality and taper, hardness where a bearing failure heat-affected the steel, whether cracks run into the fillet radius, bore wear against the largest oversize piston, bore alignment, deck and head flatness. None of it can be guessed from outside a canopy, which is why the first step is an inspection rather than a quotation request.
Usually rebuild
When repair wins
- Block, head and crankshaft clean up within the manufacturer's limits
- Parts for that engine family are available
- The installation would be expensive to redo — plant room access, cable runs, exhaust routing, approvals
- The alternator and control gear are sound, or economically repairable
Usually replace
When we say buy
- Core components are beyond machining limits
- The engine family is genuinely unsupported for parts
- The set was always undersized for the load it now carries
- A used and reconditioned set is the better buy — we would rather turn down a rebuild than do one that will disappoint
Engines we overhaul
Genset and industrial diesels
Regularly through this workshop: Perkins, Cummins, Caterpillar, Volvo, Deutz and Yanmar, the engines fitted under FG Wilson, Kohler and Onan badges, and industrial and marine engines from MAN, MTU, Detroit, Wärtsilä and Kubota. We hold no dealership for any of them.
We take large work as well as small — very small work is what we decline, not the big jobs. Send the engine model and the crankshaft or block dimensions with your enquiry and you get a straight yes or no the same day.
Common questions
Genset overhaul, answered
How much does a generator overhaul cost?
On what the measurements show — hence the two-stage quote. Anyone pricing a full overhaul before opening the engine is guessing, and the variation order arrives later.
How long does a genset overhaul take?
Engine size, what the components measure, and parts lead time. The date comes after the measurement stage, and it holds because the machining is not in another workshop's queue.
Do you send the crankshaft and head out to a machine shop?
No. Crankshaft grinding, line boring, bore honing, head surfacing and connecting-rod work are done in our own machine shop on the same site.
Can the overhaul be done on site?
Top overhauls sometimes can be, depending on access. A major overhaul cannot: the crankshaft, block and head go on machines that do not travel, so the engine or the whole set comes back to Sharjah.
What proves the overhaul was done properly?
The measurement sheet and the load bank test — one shows the components came back within the manufacturer's limits, the other that the rebuilt set carries its rating. Ask any supplier for both.
Should I overhaul the alternator at the same time?
Test it, at minimum. Insulation resistance and the excitation chain take little time while the set is apart, and finding a marginal winding after the engine is back in is an expensive way to learn about it.
Book an inspection, not a quotation
Send the engine model and serial, alternator model, rating, running hours and the symptoms — with photographs of the data plate, the breather, the exhaust and the oil filter cut open. You get back what an inspection would involve and what it would establish.