VRD carried out some engine modification work for the owner of this vintage Renault powered racing boat a little while back. The boat and highly modified engine were built in Melbourne during the 1950s and at that time the builder had bespoke pistons cast for the engine. The boat set various Australian Water Speed Records in period and the speed record for the 50 cubic inch class that this boat set in 1960 still stands! The pistons have very large crown intruders and the current owner noticed during routine engine teardown that the edges of the piston intruders were showing evidence of picking up in the bores of the piston sleeves in the direction parallel to the piston pin. VRD modified the piston intruders to relieve this area with minimal reduction to compression ratio and also measured and selectively matched various pistons and liners the owner had (this is a wet sleeve engine), before "Flexhoning" honing the liners ready for re-assembly. VRD also manufactured a simple ring lapping tool to allow the owner to lap slightly thicker new piston rings he had obtained to suit the original ring groove widths.
Following the VRD piston modifications and careful engine re-assembly by the skilled current owner, the engine has since performed reliably at various vintage racing boat meetings throughout Australia.