Hi Dunboyne,
Your engine has the early type rods, white metalled on the steel caps
Refurbishing these is pretty difficult, one method that used to be used was to bore out the rod and cap to accept shells, these then need modifying as the boring will take away some of the rod bolts, then new bolts will be needed as well
Its probably easier to source later shell type rods
It is vital to split the crank / flywheel to clean it out .
The innards will be stuffed with a hard grey sludge from the centrifugal effect. These cranks do not have removable sludge trap plugs like the later one piece cranks
New flywheel bolts/nuts will be needed for rebuild
i planned to leave well enough alone
When rebuilding old engines, this is not a good idea as inevitably the one piece you leave is the one that will give trouble at the earliest oppertunity
HTH
John