Subject: Replacement Pistons Models: 911/930 1980
Bulletin Number: 81 – 01
Beginning with 1980 models, factory-installed pistons have a weight differential of 4 grams max.
Weight identification is stamped in top of piston (-. –. +, or ++).
For replacement, however, weight differentials up to 8 grams are allowed.
Piston, Replacing
Only two piston weight classes are available for replacement of the four weight classes used in production. Therefore, pistons with – and – identification marks take one class and those identified with + and ++ take the other class for replacement
Note:
Early 1980 models and before had no piston weight identification. When replacing pistons in these cars:
- Weigh piston, together with rings, wrist pin and wrist-pin lock rings
- Find weight class from table (p.2)
- Obtain pistons by part number given in table (or consult your Parts Department)
Pistons, installing
Two manufacturers, Mahle and Schmidt, make Porsche pistons.
- Install pistons of only one company in any one engine
- Install pistons of only one weight class in any one engine
- Install cylinders (pistons and cylinders available only as sets) of same height on one side of the engine (see mark 5 or 6 on side of cylinder wall as shown)
Replacement Pistons Mahle Pistons
| Part No. |
| Vehicle/engine type | Weight/identification mark {on piston heed} | Piston with cylinder {Gr. 5} | Piston with cylinder {Gr. 6} |
| 911 SC, 78/79 models USA/Calif. -930/04/06 911 SC, 80 models only USA/Calif. -930/07 | No specifications 660 – 668g – – or – 668 – 676g + or + + No specifications* 636 – 644g – – or – 644 – 652g + or + + | 930.103.962.01 N/A 930.103.962.03 930.103.962.04 930.103.977.01 930.103.977.03 930.103.977.04 | 930.103.962.02 N/A 930.103.962.05 930.103.962.06 930.103.977.02 N/A 930.103.77.05 930.103.977.06 |
| *Some early 80 models were built with pistons having no weight specification. If these need to be replaced, pistons with weight specification can be used. | |||
| 911 Turbo, 78/79 models |
| USA -930/61 Calif. -930/63 | No specifications 601 – 609g – – or – 609 – 617G + or + + | 930.103.969.01 N/A 930.103.969.03 930.103.969.04 | 930.103.969.02 930.103.969.05 930.103.969.06 |
| Schmidt Piston | |||
| 911 SC, 78/79 models | |||
| USA/Calif. -930/04/06 | No specifications 695 – 703g – – or – 703 – 711g + or + + | 930.103.966.01 930.103.966.03 930.103.966.04 | 930.103.966.02 930.103.966.05 930.103.966.06 |
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