Friday, 14 November 2014

Lowering height of cylinder as an experimental alternative to a longer conrod -required due to lower piston compression height.
Not easy when the task is just on the border of the capacity of my lathe. Low speed is the answer though.

Always seems a shame to have to strip everything apart at the end of the season but I am putting in a different engine so everything within the cradle must come out. I have tried doing it by leaving the gearbox in and raising the engine but it is more trouble than it is worth.

Having recently bought an old oil pump  found it to be seized through not used. This is very common as the main body is made from Mazak- the British trade name for Zamak. It is an alloy which shrinks with extended age. This feature is fine if used regularly as it takes up wear on the pump wheels but leads to seizure if left idle.
It was used due to being cheap and very easily die cast- being zinc based- for jobs like this. The only solution I have found is to dismantle the pump with great care - heat the body so that it is too hot to hold ( it is cold in the photo!) and use circlip pliers and much metal polish such as Brasso to free each impeller wheel round and then when each is done do it for the assembled pump.

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