Crankshaft grinding & polishing

The backbone of the engine

Knocking from the engine? Low oil pressure? The crankshaft converts the up-and-down motion of the pistons into rotation. It is one of the most heavily loaded components in the engine and takes enormous forces on every combustion cycle. Even though crankshafts are made from high-strength steel or tough cast iron, the bearing journals wear over time, especially if oil changes are neglected or the engine is driven hard.

At Meksta we have experience reconditioning crankshafts from virtually every engine type. We grind, polish and balance, and we do it with the precision required to keep the crankshaft running for many thousands of miles more.

Precision grinding of bearing journals

When the bearing journals on the crankshaft are worn, scored or oval, they are ground down to the next undersize. The manufacturer usually specifies 2-3 undersize steps (for example -0.25, -0.50 and -0.75 mm). For each step there are matching undersize bearings available to buy.

The grinding is carried out on a dedicated crankshaft grinder, where the crankshaft is ground to exact undersize with a controlled surface finish. The result is a perfectly round, straight bearing journal with the correct finish for optimal oil retention.

We grind both main journals and rod journals. Every journal is measured before and after with a micrometer to guarantee the dimensions are within specification.

Polishing of bearing journals

Polishing is used when the bearing journals are within dimensional tolerance but have minor scratches, marks or surface imperfections. Polishing the journals with fine abrasive paper or a polishing belt improves the surface finish without changing the dimension appreciably.

Polishing is also common as a final step after grinding to achieve an even better surface finish. A well-polished bearing journal reduces friction and improves oil retention, which extends the life of both the bearings and the crankshaft.

Balancing alongside grinding

An unbalanced crankshaft creates vibrations that increase with rpm and wear on bearings and seals. We often balance the crankshaft together with grinding, especially on V8 engines and performance builds where the engine will be revved high. We describe the full process, the methods and the pricing on our page about crankshaft balancing.

Crack detection

Before grinding we always check the crankshaft for cracks. We use magnetic particle inspection (Magnaflux), where the crankshaft is magnetised and dusted with iron powder that collects in any cracks. Even microscopic cracks invisible to the naked eye are found this way.

A cracked crankshaft cannot be repaired and must be replaced. Finding a crack before assembly saves both time and money compared with a failure in service.

What does crankshaft grinding and balancing cost?

The prices below apply to typical 4-cylinder engines and are excluding VAT. V6 and V8 engines are quoted separately. You always get an exact quote after inspection.

All prices excl. VAT. V6, V8 and larger engines cost more. See the full price list

Engine types we work with

We recondition crankshafts for all types of combustion engines:

• Cars (all makes, petrol and diesel)
• Motorcycle engines
• Marine engines (inboard and outboard)
• Industrial engines and generators
• Classic cars and vintage vehicles
• Race and performance engines