Setting the Silk oil pump by Kevin Bayliss
The Silk oil pump is a good quality pump which requires very little maintenance.
The worm drive was a unit just bought locally of the shelf and was fitted with the gear which has two cams on it. These push up the two little pistons which have oil groves in them, no rings or seals are on the pistons.
Two drillings are used to transfer the oil via the pistons which are spring return.
The top of the unit has another spring loaded plate where the oil flow adjuster is located. The oil flow is controlled by the throttle.
As the throttle opens this pulls the oil flow control lever round which lifts the top plate effectively increasing the length of the piston travel giving more oil.
Once the oil has been “pumped” the oil exits from the rear of the block via “o” rings to the oil case and to the engine case.
As the oil goes into the engine, the right hand side of the crank is directly fed via drillings to the non return valves which are located in the engine case main bearing block. (Two for each side, 1 for each main bearing)
The left hand is fed to a cross over pipe and then into the two left hand non return valves.
Warning if you have a loose alternator screw you may loose oil from the drilling to the oil way as they are the one and same.
There is no need for oil pump timing as when the piston is travelling down the bore the non return valve has shut enabling a slight increase of oil pressure in the drillings. As the piston starts to travel upwards the crankcase vacuum helps the oil pressure to open the non return valve and feed oil directly into the main bearings.
The oil then travels through drillings in the crank web and with the rotational forces of the crank turning the oil is forced into the crankcase where it is mixed with petrol and finds it way into the big end bearing. There is a slot in the top and bottom of the conrod for lubrication.
I normally set the throttle fully open and adjust the oil pump cable to max without straining the cables. Once running and settled if the smoke is too much you gradually slacken the oil pump cable until the right amount of smoke is produced.
After an engine rebuild, add oil to the tank fuel as the drillings WILL take time to fill and you could have a seized engine before oil starts to do its job.
These engines are far too valuable to waste, you need smoke but not too much as the mixture will become weak and you'll start causing other problems.
Kevin Bayliss
The worm drive was a unit just bought locally of the shelf and was fitted with the gear which has two cams on it. These push up the two little pistons which have oil groves in them, no rings or seals are on the pistons.
Two drillings are used to transfer the oil via the pistons which are spring return.
The top of the unit has another spring loaded plate where the oil flow adjuster is located. The oil flow is controlled by the throttle.
As the throttle opens this pulls the oil flow control lever round which lifts the top plate effectively increasing the length of the piston travel giving more oil.
Once the oil has been “pumped” the oil exits from the rear of the block via “o” rings to the oil case and to the engine case.
As the oil goes into the engine, the right hand side of the crank is directly fed via drillings to the non return valves which are located in the engine case main bearing block. (Two for each side, 1 for each main bearing)
The left hand is fed to a cross over pipe and then into the two left hand non return valves.
Warning if you have a loose alternator screw you may loose oil from the drilling to the oil way as they are the one and same.
There is no need for oil pump timing as when the piston is travelling down the bore the non return valve has shut enabling a slight increase of oil pressure in the drillings. As the piston starts to travel upwards the crankcase vacuum helps the oil pressure to open the non return valve and feed oil directly into the main bearings.
The oil then travels through drillings in the crank web and with the rotational forces of the crank turning the oil is forced into the crankcase where it is mixed with petrol and finds it way into the big end bearing. There is a slot in the top and bottom of the conrod for lubrication.
I normally set the throttle fully open and adjust the oil pump cable to max without straining the cables. Once running and settled if the smoke is too much you gradually slacken the oil pump cable until the right amount of smoke is produced.
After an engine rebuild, add oil to the tank fuel as the drillings WILL take time to fill and you could have a seized engine before oil starts to do its job.
These engines are far too valuable to waste, you need smoke but not too much as the mixture will become weak and you'll start causing other problems.
Kevin Bayliss