I'd heard that the early cam gives better performance but never looked up the specs before. My CIS injection 99 factory book is a '75 only book, but the Haynes manual spec page says all cams are the same from '75 on. They don't show a different grind for carb and K-jet injected so I wouldn't completely believe them, since the '75 factory book does.

I'm giving specs from the various factory manuals.

TDC= Top Dead Center
BDC= Bottom Dead Center

Valve timing '72-'74:
Inlet (nominal valve clearance 0.25mm) starts 26º BTDC ends 70º ABDC
Outlet (nominal valve clearance 0.45mm) starts 70º BBDC ends 26º ATDC

Valve timing Carbureted engines '75:
Inlet (nominal valve clearance 0.35mm) starts 12º BTDC ends 56º ABDC
Outlet (nominal valve clearance 0.55mm) starts 56º BBDC ends 12º ATDC

Valve timing K-jet injected engines '75:
Inlet (nominal valve clearance 0.35mm) starts 10º BTDC ends 54º ABDC
Outlet (nominal valve clearance 0.55mm) starts 46º BBDC ends 18º ATDC

Valve timing K-jet injected engines C-900 '79-'80:
Inlet (nominal valve clearance 0.35mm) starts 10º BTDC ends 54º ABDC
Outlet (nominal valve clearance 0.55mm) starts 46º BBDC ends 18º ATDC

I'm not sure if the '78 99 Turbo has the same grind as other '78 99s. I don't have those specs. The '79-'80 99 probably has the same grind as the non-Turbo C-900s of those years.

Valve timing K-jet injected Turbo engines C-900 '79-'80:
Inlet (nominal valve clearance 0.35mm) starts 12º BTDC ends 40º ABDC
Outlet (nominal valve clearance 0.55mm) starts 62º BBDC ends 2º ATDC

Generally the longer the duration of the open time and the longer the overlap between the intake opening and the exhaust closing, the better the engine breathes. Exhaust scavenging helps to draw the intake gases into the cylinder. The earlier (longer duration and overlap) cams may effect your ability to pass emissions inspections.

Interestingly, I remember my old boss telling me that the Lotus Europa 16-valve engines had a different grind on one exhaust lobe than on the other. I think that the swirl that was created by the different timing helped performance.

posted by 207.225.8...

• saab 99 performance parts, Andreas, Tue, 20 Nov 2001 13:59:00
  • Re: Cam for any '72-'74 is the better grind..., Andy in PDX, Thu, 22 Nov 2001 01:20:48 <-- Viewing This Message
    • These are US cam specs. Europe is likely different., Andy in PDX, Thu, 22 Nov 2001 01:23:24
  • cam from a '74 99 should do the trick (n/m), ROSS, Tue, 20 Nov 2001 18:08:55
    • just any '74 99? L, GL, GLE, EMS, Turbo or whatever?, Andreas, Wed, 21 Nov 2001 05:29:25
      • Re: just any '74 99? L, GL, GLE, EMS, Turbo or whatever?, mark, Wed, 21 Nov 2001 11:02:18
        • I think all models got same cam, tho inj. & carb ? n/m, BobD, Wed, 21 Nov 2001 17:09:31
          • yes,74 efi,ems cam is the best for performance n/m, mudpuppy, Thu, 22 Nov 2001 11:11:41
          • Ross is correct, '74 cam is unique and, GreggC, Wed, 21 Nov 2001 18:18:09
            • 74 efi only 110hp, 76 CIS- 118hp, john, Sat, 1 Dec 2001 13:24:18

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