Getting into the bottom end of my June 1972 manufacture 750 Combat roadster - s/n 209xxx . I believe it to have approximately 15k miles , so relatively low mileage.
I found this surprise when removing the oil pump. The large piece was lying in the scavenge side oilway with one end in the pump - the small piece was in the scavenge side of the pump itself where it worked it's magic on the gears. Obviously it was drawn up from the sump. Anyone know what it might be ? It looks like a piece of piston ring yet all rings are intact and there is no scoring of the bores which are still at standard bore and show cross hatching all around .
I should add that I have split the cases and all seems in order with nothing missing and no further shrapnel in the sump .
too big to go through a sump filter, stupid not to have one.
The first time that I stripped my Mk3, I found a cam follower foot in the sump...and all four followers in the cylinder were intact...It could be ring.
Could it be a bit of a spigot filler ring - which someone dropped into the sump after a previous piston catastrophe?
How did it get around the junction of the oilway in the RH casing. It was in there from last build / original build - check the junction in the right hand case, it is where debris accumulates as there could be more, especially on the Combat case.
......are known to break off. These thrust washers are unique to Combats I believe.
I have machined a sump extension to add on to my combat, the insides of the cases are witness to its grenade like qualities. It will add in a gauze and an extra magnet and be accessible from underneath the cases. The engine will be full combat with superblends, reed breather at the back of the cases and all the other mods ie pickup at rear but if it does go then at least the pump will be safe.
As Ashley pointed out it seems that it is unlikely that the complete piece which measures 5/8 " in length could make the 90 degree turn at the top of the oilway . If it couldn't then that leaves only two options- it was the result of some careless manufacturing and has been there all along or it was placed there deliberately by some disgruntled soul. I have also discovered a repair in the area of the blanking screw for the long horizontal drilling at the the back of the engine but I don't believe it could be related because the intersecting oilways are even greater than 90 degrees and it certainly could never have gotten past that junction .
It can be seen in the photo that it does not appear to be from the camshaft thrust washer but , as Michael so rightly points out , the tab is indeed fatigued and ready to fail .
Epoxy repair @ Blanking screw
Thanks all for their responses. I am now reasonably certain that the shrapnel is from a piston ring . It would seem as though the rings were redone and that would explain the good condition of the bores .
As can be seen in the first picture some genius in the past tried to pry the crank pinion off rather than use the proper puller - witness the slight fracture above the shaft at the 10 o'clock position . Fortunately it is superficial and I think I can draw the deformity of the housing on the timing chest side in with a die turned to a sliding fit of the bearing diameter while the case is still hot from bearing removal.
I have removed all the blanking screws from the oilway drillings and all good in that department . The epoxy repair mentioned above must have been an attempt to stop a leak without having to deal with removing the staked blanking screw - I have removed the epoxy and there is no sign of any damage there thankfully .