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PRTEngine Reconditioning

Crankshaft

Crankshaft Grinding

Restore worn journals to size and true running geometry. Crankshaft grinding returns main and crankpin journals to specification for use with matching undersize bearings.

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What this covers

  • Inspection, measurement and straightness assessment
  • Main and crankpin journal grinding to required undersize
  • Journal fillet and oil-hole condition management
  • Finish and geometry verification after grinding
  • Matching undersize bearing guidance

Overview

A straight crank is a smooth engine

Worn, scored or tapered journals wreck bearings and put unwanted load through rods and pistons. Grinding restores each journal's size, roundness, surface finish and — critically — its alignment and stroke geometry.

The crank is inspected, measured and straightened or checked first, then ground to the required undersize so new matching bearings can be fitted. Finish and geometry are verified after every stage.

Reconditioned to measurement

Reconditioned to measurement. Not guesswork.

Decisions on crankshaft grinding are made from recorded measurements against specification — never from how a part “looks”.

Inspect · Measure · Machine

Symptoms

When is this work needed?

These are the problems and symptoms that typically point to the component needing reconditioning work.

  • Knocking or rumble from the lower end
  • Low or fluctuating oil pressure
  • Scored or spun bearings on strip-down
  • Measured journal taper, ovality or wear
  • Vibration traced to crank geometry

Inspection

Inspected and measured before machining

5 checks and measurements inform the decision to machine — nothing is cut until the component has been assessed.

  • Main and crankpin journal size, taper and ovality
  • Run-out and straightness of the crank
  • Fillet radii and oil-hole condition
  • Keyways, threads and flange faces
  • Crack detection where history or condition warrants it

Measurement & quality

Journal geometry is the deliverable

An undersize bearing is only as good as the journal it runs on — size, roundness, surface finish and alignment are all verified.

Verified after machining

  • Journal size held to the chosen undersize
  • Taper and ovality checked per journal
  • Run-out verified to keep the crank true in the engine

PRT process

How we carry out the work

  1. 01

    Receive & inspect

    Journals, fillets, oil holes and the overall condition are assessed.

  2. 02

    Measure

    Journal sizes, run-out and straightness are recorded to plan the grind.

  3. 03

    Grind

    Main and crankpin journals are ground in the correct sequence to the required undersize.

  4. 04

    Verify finish

    Roundness, size, surface finish and alignment are checked against specification.

  5. 05

    Protect & return

    Journals are protected against damage in transit and handling.

Machinery & stations

Performed at the right station, with the right tooling

Detailed equipment make, model and specification sheets are pending from PRT. The functional stations involved in this service are:

  • Crankshaft grinding station
  • Straightening and inspection set-up
  • Precision measuring & gauging area

Gallery

From the PRT shop floor

Authentic PRT photography will appear here as it is captured and approved. No stock imagery.

Shop floor

Crankshaft Grinding work in progress at the PRT facility.

Machining close-up

Real photography of the operation will appear here when PRT approves imagery.

Finished result

Before-and-after records of PRT jobs are published as real projects.

Related services

Work that belongs with this one

Connecting Rod Reconditioning

Restore rod bores, alignment and fastener condition. We check, measure and recondition connecting rods so each rod is straight, correctly sized and ready for the rebuilt assembly.

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Cylinder Block Reconditioning

Strip, inspect, measure and machine the engine's foundation. We recondition cylinder blocks for rebuilds — cleaning, crack detection, boring and honing, deck surfacing and, where needed, line boring of the main bearing housings.

View service

Engine Assembly

A controlled, clean, torque-accurate build. We assemble reconditioned engines from measured components — so the finished unit leaves the shop built to specification and ready to run.

View service

FAQ

Common questions

Straight answers to the questions we expect about this service.

What undersizes are ground?

Journals are ground to the undersize the rebuild requires, matched to the bearings available for that engine. The required undersize is confirmed from measurement before grinding.

Can a bent crankshaft be repaired?

Straightness is checked first and assessed against the crank's specification and condition. Not every crank can be economically or safely straightened — the decision is made from measurement.

Should the crank be ground on every rebuild?

Only if measurement shows it is required. Where journals are within specification, the crank is cleaned, inspected and reused as-is.

Get a Quote

Discuss a crankshaft grinding job

Tell us the engine or component, its condition and what the rebuild needs to achieve. We will confirm the scope from an actual assessment.

Request a quote