Skip the crankshaft checks and the risks are serious. New bearings on a damaged or out-of-limit journal fail again within hours. A hidden crack can lead to a broken crankshaft and a destroyed engine block. That means a second failure, a much longer outage, lost production, and a repair bill far larger than doing it right the first time.
USP&E Helps You Repair It Once
We know you want the engine back in service fast, but not so fast that it fails again. USP&E has delivered 150+ power projects in 45+ countries, with 25,000 MW contracted since 2002, and our 400+ engineers and project managers inspect, rebuild and maintain diesel engines and gas turbines. Our systems are ISO 9001 and ISO 45001 certified, and every deal runs under FCPA and OFAC controls. USP&E is a full-service EPC and O&M contractor, not a broker.
You do not need to replace every crankshaft that has seen a bearing failure. You need careful measurement, proper crack testing and a clear rule for when to grind, repair or replace.
Read the Symptoms Before You Open the Engine
Start with the history. Look at recent oil analysis for bearing metals, oil pressure trends, any overheating or overspeed events and any change in noise or vibration. A sudden bearing failure after low oil pressure points one way; slow wear over thousands of hours points another. The cause matters because it tells you what else may be damaged and what must be fixed so it does not happen again.
Check the lubrication system as part of the diagnosis: oil pump, filters, cooler, pressure relief valve and oil quality. A crankshaft repair that leaves a weak oil pump or a blocked cooler in place will fail again. Check the torsional damper too, because a failed damper can overload the crankshaft and lead to cracks.
Record what you find with photos and readings. This record supports the decision you make later and helps if the failure leads to a warranty or insurance claim.
Measure, Crack Test and Decide
Measure every main and crankpin journal for diameter, roundness and taper, and compare the results with the engine maker’s limits. Check the journals for scoring, heat marks and hardness damage. Measure crankshaft run-out and check the thrust faces. A journal that looks fine can still be out of round enough to destroy new bearings.
Crack test the crankshaft with a method suited to it, such as magnetic particle inspection, paying close attention to the fillets and oil holes where cracks usually start. A cracked crankshaft is normally replaced, not repaired. Heat damage may also have changed the hardness of the journal surface, which must be checked before grinding.
If the crankshaft is sound but worn, grinding to an approved undersize with matching bearings may restore it. If damage is beyond the limits, replacement is the safe choice. Our engine refurbishment services cover both paths, and the Cat 3500 overhaul notes show how this fits a full overhaul.
Rebuild Carefully and Carry the Discipline to GT
On rebuild, clean every oil passage thoroughly, because debris from the failure can destroy new bearings within minutes. Fit the correct bearings for the journal size, check clearances, torque bolts to the specified values and record every measurement. Prime the lubrication system before the first start and run the engine in on a planned load schedule while you watch oil pressure and temperatures.
Follow up with oil analysis after the run-in and at short intervals for the first weeks. Any rise in bearing metals is an early warning. Keep the full repair record with the engine so the next team knows exactly what was done. Our sister site covers day-to-day diesel service routines that help prevent a repeat.
The same rotor discipline applies to gas turbine generators. Whether you move to used/new gas turbines, a remanufactured GE Frame 6B or natural gas engines/stations, rotor inspections, bearing checks and oil analysis protect the most valuable parts. Data centre sites use the same habits under hyperscale EPC/O&M with AI gas turbines, hyperscale generators and gas turbines for compute, including the New USP&E FX-45 45MW Modular Gas Turbine for the Hyperscale Data Center sector in the USA.
USP&E Teams Behind Your Diesel Repair Site
Remote sites need people who know frontier work. USP&E runs your diesel balance-of-plant repair and GT upgrade from Johannesburg (22 Kildoon Rd, Bryanston) and Cape Town (31 Brickfield Road, Woodstock), where engineers plan mobilisation, spares and site supervision for projects far from the nearest service shop.
Further back in the chain, London (162-168 Regent Street) handles financing and contract structure for diesel BOP spares, rebuilt engines and gas turbine packages; Colorado Springs (1755 Telstar Dr, Suite 300) and Knoxville (800 S Gay St, Suite 700) secure US equipment, parts and engineering support; and Wuxi, China (No. 1, Ningzhou Road, Wuxi) keeps Chinese-made switchgear and balance-of-plant moving.
For crankshaft repairs on generator engines, Johannesburg and Cape Town workshops and field teams cover African sites, while Wuxi follows up replacement parts made in China. Regions served: USA | AFRICA | UK | UAE | CHINA. That team has carried 150+ power projects in 45+ countries and 25,000 MW contracted since 2002, ISO 9001 and ISO 45001 certified.
What USP&E Has Delivered for Diesel Repair Buyers
You want proof that USP&E can repair and restore large engine fleets. These projects show that record.
- USP&E supplied 28 Cummins KTA50 containerised diesel gensets, 1,275 kVA each, for Perseus Mining’s Nyanzaga Gold Project in Tanzania.
- Mining O&M recovery, Mali: USP&E took over a 100+ MW plant of 15 Cat CM32 engines left in critical condition, restored availability to about 95% and cut maintenance and repair cost per engine by 66%. Read the case study.
- Resolute Mining, Golden Pride, Tanzania: a new USP&E controls system integrated two engine brands in one plant and eliminated harmonic distortion on the mine network. Read the case study.
HowTo: Inspect a Diesel Crankshaft and Plan for GT
Your 3-step plan: 1. Share the failure history, oil analysis and engine details. 2. Receive an inspection plan and a clear repair or replace advice. 3. Rebuild, run in and support the engine with accountable O&M.
- Record the symptoms: bearing failures, oil analysis results, noise or vibration.
- Measure the main and crankpin journals and compare them with the engine limits.
- Crack test the crankshaft before any decision is made.
- Decide whether to grind, repair or replace, based on the findings.
- Fit the right bearings and record clearances on rebuild.
- Apply the same rotor inspection discipline to your gas turbine plan.
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FAQ: Diesel Repair Crankshaft Inspection Path to GT
What are the signs of a crankshaft problem in a diesel generator?
USP&E looks for bearing failures, rising bearing metals in oil analysis, low or falling oil pressure, new knocking and changes in vibration. Any of these means the crankshaft must be measured and crack tested before new bearings are fitted and the engine is closed up.
Can a damaged crankshaft be ground and reused?
USP&E grinds crankshafts that are sound but worn to an approved undersize with matching bearings. A crankshaft with cracks, damage beyond the limits or heat damage that has changed surface hardness is normally replaced. Measurement and crack testing decide which path is safe.
Why must a crankshaft be crack tested after a bearing failure?
USP&E crack tests because heat and shock from a bearing failure can start cracks in the fillets and oil holes. A hidden crack can lead to a broken crankshaft and a destroyed engine block, so testing protects you from a much larger failure later.
What should be checked besides the crankshaft?
USP&E also checks the oil pump, filters, cooler, pressure relief valve, oil quality and the torsional damper. If the cause of the failure is left in place, the new bearings will fail too. Fixing the cause is as important as repairing the crankshaft.
Where are USP&E’s offices for engine repairs?
USP&E supports engine repairs in Africa from Johannesburg and Cape Town, with field teams that travel to site. Knoxville and Colorado Springs support US work, London handles contracts and finance, and Wuxi follows up crankshafts, bearings and other replacement parts made in China.
Has USP&E delivered large engine repair work before?
USP&E took over a Mali plant of 15 Cat CM32 engines left in critical condition, restored availability to about 95% and cut repair cost per engine, as a public case study shows. A controls upgrade at Resolute’s Golden Pride mine is another public example.
Is USP&E a broker for engine repairs?
USP&E is not a broker. USP&E inspects, rebuilds and maintains engines with its own engineers, so the team that measures your crankshaft is the same team that rebuilds the engine, runs it in and stays accountable for the result on your site.
How fast can USP&E advise on a crankshaft repair?
USP&E can start reviewing your failure history, oil analysis and engine details as soon as you share them. Engineers flag the likely cause and the checks needed first, so inspection can begin as soon as the engine is safe to open.
Fix the Crankshaft Right the First Time
Measure, test and rebuild with care and your engine returns to service for the long term. Rush it and the second failure costs far more than the first. USP&E will help you inspect, decide and rebuild with confidence.
Talk to an engineer about your diesel balance-of-plant repair and GT upgrade: use the USP&E contact page, call +27 10 822 2324 or email info@uspeglobal.com. You can also search the USP&E inventory for equipment that fits.
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