Technical drawing of a Specialloid Y Alloy piston for a 6-cylinder engine.
| Identifier | ExFiles\Box 148\4\ scan0308 | |
| Date | 26th September 1941 | |
| SPECIALLOID PISTON R88 ROLLS-BENTLEY 6 CYL. DRG No EB.025 ROLLS-ROYCE LTD SPECIALLOID Y ALLOY HEAT TREATED ALL RING GROOVE WIDTH LIMITS ± .002 .8255 (3 1/4) DIA SEE LAND TABLE .7575 DIA ± .10 68.5 DIA 1/8 FILLETS ON HEAD & SIDE OF WEBS FROM JOINT UP TO HEAD REMOVE SHARP EDGES 12 - 5/32 DIA HOLES X SPACED AS SHOWN IN PLAN VIEW 6 - 1/8 DIA HOLES Y SPACED AS SHOWN IN PLAN VIEW WEBS TAPERED 3 TO 1 1/2 * FOR OVERSIZE PISTONS THESE DIAS TO BE INCREASED CORRESPONDINGLY * 82.00 DIA AXIS TT, 81.87 DIA AXIS PP FOR BALANCING WT TOLERANCE ± 2 DRAMS 2 - 1/8 DIA HOLES DRILLED THRO BOTTOMS OF BOSSES PIN TO BE ROUND & PARALLEL WITHIN .0001" ENDS TO BE SQUARE. BORE TO BE SMOOTH & FREE FROM SCALE OR FOREIGN MATTER TO BE DRILLED & REAMED AFTER CARBURISING. MATERIAL 3S15 (3% NICKEL) CASEHARDENED DEPTH OF CASE .020" CLEARANCES TABLE: DEDUCT FROM CYLINDER BORE LANDS | AXIS T.T. | AXIS P.P. A | .40 | .53 B | .30 | .43 E | .23 | .36 LMT ON DIA D | ± .012 | ± .012 TAPERED TO D1 | .13 | .26 LIMIT ON DIA D1 | .09 | .22 OVALITY OF PISTON .13 13. M.M. = 5.2 THOUS .09 M.M. = 3.6 THOUS RINGS TABLE: | TYPE | WIDTH | DEPTH 1ST | PLAIN | 3/32 | 108/116 2ND | " | " | " 3RD | " | " | " 4TH | RAD. SLOTTED | 3/16 CIRCLIPS 204 AX 1c DIES TABLE: BODY | C 253 M. {Mr Moon / Mr Moore} TOP RING BOT. RING TOP | C 28 BOTTOM | C CROSSHOLE BRUSH | C124 CORE BOX | R88 CYL BORE +.001/-.000 SEE STD. CHARTS FOR LIMITS ON MACHINED DIMENSIONS UNLESS OTHERWISE STATED ALTERATIONS SPECIALLOID PISTON (bottom left) BRITISH PATENTS: No. 227641, No. 364787, No. 399801, No. 2739/32 REG. DESIGNS: No. 685933, No. 775780 STAMP: SPECIALLOID LTD. * 10 OCT 1984 * DRAWING OFFICE DRAWN 26/9/41 CHECKED 26-9-39 APPROVED | ||
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).