Why do you file piston rings instead of buying pre-gapped rings?
Documented on the Chevrolet Small Block 350 (sbc 350) build
Published March 28, 2026
Many rings must be filed to match the specific bore diameter and application to achieve correct end gap at operating temperature.
Full Answer
Many rings must be filed to match the specific bore diameter and application to achieve correct end gap at operating temperature. Pre-gapped rings may not match your precise bore size or intended oil control/boost conditions, so filing allows custom fit to spec.
Documented In This Build
Related Knowledge
How much end gap should I aim for on a SBC 350?How much material should I remove when filing a ring?What if my main clearances are out of spec?Is plastigauge accurate enough for checking main clearances?How important is degreeing the cam?What torque sequence and values should I use for SBC heads?How do I set lifter preload or hydraulic lash?What should I do to prepare the engine for first start and break-in?
Related Parts
Assembly lube
$15
Main bearing set
$60
Piston ring set
$120
Plastigauge (assorted)
$8
Related Tools
Torque wrench
Engine stand
Feeler gauges
Ring filer / hand file
Micrometer / inside micrometer
Plastigauge
Ring compressor
Related Videos
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Small Block Chevy 350 Build Pt. 11 | Installing the intake manifold and figuring out sbc nuisances
Small Block Chevy 350 Build Pt. 7 | Checking Crank Clearance and installing the rods.
Small Block Chevy 350 Build Pt. 8 | Installing Camshaft and timing components
Small Block Chevy 350 Build Pt.1 | Lifting This Engine Without Breaking It