Petrol engines aircooled push rod & seal replacement

Meggles: Forum post on aircooled pushrods and tube seals

Remove rocker cover by prising off the retaining spring clip.

Remove the thin wire retaining clip which holds tubes in place(It has lots of bends in it, note how it fits).

Remove the bolts securing the rocker shaft.

Remove pushrods and note where they were from.

Carefully twist the tubes, especially if they are old and corroding (if too bad they'll need replacing), and ease away from the engine whilst still twisting, until they come loose.

Remove old seals and where the seals sit (both ends) in both the engine block, head and tubes give a good inspection and clean old seal bits out..

Grease/oil the new seals and put them on the tubes (different size at each end), and carefully replace tubes, twisting as you press them in (you'll feel them slot in to place).

Replace rocker shafts (11lb torque on nuts)

Replace the wire retaining clip (you took note of how it was removed, didn't you!!!). Initial setting for rockers is to:

Position engine at TDC and slacken rocker nut on No1 cylinder, undo screw until it is no longer contacting rocker and then screw back in 'til it just makes contact with rocker. Now tighten 1/2 further turns and tighten locknut. Repeat for cylinders 2,3 and 4 by turning engine a quarter turn (distributor rotor will move by 90 degrees) in an anti clockwise direction. Replace rocker cover (new gasket). Hold gasket in place with sealer or similar. Best to use just common or garden multi grease on rocker cover gaskets, silicon makes it a one time seal, new gaskets every time .