New piston blanks based on the Hepolite piston made for the Silk machines should be available from the end of February 2013
These blanks come in two versions
9066 version being for Short Stroke pistons starting at plus 30 thou over standard size
9066A version being for Long stroke pistons starting at plus 30 thou over standard size
The only difference is the skirt internal diameter which is bigger on 9066 to keep weight low in larger sizes.
The blanks can be used to produce both Short Stroke and Long Stroke variants.
The 9066 dies will produce a piston entirely suitable for Silk Owners. It should be remembered that in order to source quality lightweight pistons by the multi piece totally metal die process, George Silk had to purchase 1000 pistons all to the same size. The costs were very considerable and so the option of different oversizes was uneconomic. It is for this reason that to restore a worn Silk engine, it is necessary to have the barrels resleeved, which is a specialised and expensive operation. The availability of piston blanks from the 9066 dies will enable Silk owners to have economical rebores and new oversize pistons fitted in the orthodox manner.
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