So , block at machine shop for bake n clean etc . A couple basic oil passage mods . I prepped new timing cover and set up pump with new stock spec gears and plate kit . Gear clearance was about .004 . Anyway - question about the cup/Piston the spring fits into . It slides into the preliminary bore fine but when it hits the secondary bore it takes some pressure to get it to seat . Is that normal ? Does not seem like it wants to slide easy . And I tried a couple different housings and pistons - same sorta .
have a bunch of covers but never noticed an excessive tightness with the piston. should be a slip fit. any burrs on piston or bore, maybe shellac inside?
I actually buffed the piston a little and looked inside housing , seems ok . It got the usual parts cleaner soak , brake spray and scrub clean out . I have 2 other covers and extra new and used pistons - I'll compare and experiment a little . And the 2 oval slots in piston , there's no correct direction for those correct ? No rush , planning on engine assembly over the winter .
Where it first slides in (preliminary) , then the opening , then the piston seating area (secondary , inner recess)
so , pulled cover , removed spring etc . had to work piston out . measured that piston and others - all in the .598 - .597 OD range . tried that piston in other covers - not bad . so , my cover inner section must be a little dif or dirty ? cleaned it out with a long stiff bristle engine cleaning brush with a little WD40 . twisted 'er in n out pretty good . brake clean and rinse and a good blow out . reinstalled original ( new ) piston - pretty good . definitly better . a couple good taps on table and piston slides out by itself . would not do that before . gotta double check my gear clearance - long gear does not want to turn easy enough . * also found some old KB #18101 oil pump spring kits if anyone wants one . pretty high tech early 80's !!
