CP Pistons for RB25DET Engines

  • Available in:
    Bore: 86mm (STD) / Comp: 9.0:1
    Bore: 86.5mm (+0.5mm) / Comp: 9.0:1
    Bore: 87mm (+1mm) / Comp: 9.0:1
    Bore: 86mm (STD) / Comp: 8.5:1
    Bore: 86.5mm (+0.5mm) / Comp: 8.5:1
    Bore: 87mm (+1mm) / Comp: 8.5:1

We don’t keep STD bore pistons in stock and if you order these in we will not exchange or accept returns. STD bore size pistons are not recommended in a used bore for any performance engine unless re-sleeving the block back to std bore size. All piston manufacturers have a specific piston to bore clearance that they recommend. When using a used std bore there is already wear in the bore, hence the manufacturers piston to bore clearance cannot generally be met due to the existing wear in the used bore, especially after honing the used bore. Excessive piston to bore clearance tends to cause early and excessive blow by issues.
Most piston manufactures recommend going to the first oversize and having the cylinder block bored to suit the new pistons with the recommended piston to bore clearance.