In Reply to: You're assuming that there wasn't a glitch, AdamB [Profile/Gallery] , Fri, 16 Apr 2004 02:42:52

I do not know if you all are familiar with the fact that viggen pistons are very weak indeed. The reason for this is the uppest piston ring that is located very high on the piston body. Origianlly the ring is placed there to keep emissions low. The down side is that the piston will crack relatively easy. I my self am also a reader of STCS (saab turbo club of sweden) and there has been numerous posts about this issue. Nordic has reported that they have run across twenty or so stock viggens/9-5 aeros that have cracked a piston.
To make matters more difficult the piston brake is sometimes due to leaking injectors. A leak in a injector may cause a beginning crack to the piston if it leaks when the engine is turned of. The leaked gas will fill the place above the top pison ring and once the car is started the compressions will do the trick. You can see this on the picture below. If nothing is done the piston will eventually brake completely.


Matun tried to run a 9-5 aero tuned to 350Bhp with original pistons, but the broke them twice. So 350Bhp is too much, but where does the line go?

There has been some modifications to viggen piston under the yers. To my knowledge MY99, MY00 and MY01- all have different ones. The ones in MY00 should be the weakes and there has been the most failurs in them.

Looking at the matter from this point of view Steve88SiS's mods may not after all have nothing to do with the fact that his piston(s) failed on him. Even running with stock output could have lead to the same situation, we will never know. It is true that a higher engine output will raise the risk of brake, but it like I said it might not be the "whole truth".

Mayby Sasse, the nordic guy could shine little more light to this piston issue?

Anyway here is one picture that the guys from nordic posted to STCS some while back. The red arrow points to the place where the crack begins.



posted by 192.89....

• Saab's not gonna cover it!!, Steve88SiS, Thu, 15 Apr 2004 14:57:16
  • Maybe I should get a rwd V8 car w/ a blower - nah!!, Steve88SiS, Fri, 16 Apr 2004 17:48:04
    • come on steve...go all out!!, nickR, Fri, 16 Apr 2004 19:45:29
      • It will be interesting, but my car will be ......, KevinY, Sat, 17 Apr 2004 22:39:51
        • Re: It will be interesting, but my car will be ......, TERRY, Sat, 17 Apr 2004 23:01:15
  • I would negotiate, davenew, Fri, 16 Apr 2004 15:35:00
    • Boost was 18psi a/f ratio was good, Steve88SiS, Fri, 16 Apr 2004 17:45:07
      • Re: Boost was 18psi a/f ratio was good, Brad, Fri, 16 Apr 2004 18:52:43
        • torque limit, davenew, Sat, 17 Apr 2004 14:36:52
  • My Viggen story, Philip HS, Fri, 16 Apr 2004 11:38:44
    • 2004 viggen?, nickR, Fri, 16 Apr 2004 12:25:10
      • Re: 2004 viggen?, AdamB , Sat, 17 Apr 2004 03:25:42
      • more on forged pistons, nickR, Fri, 16 Apr 2004 12:29:19
        • Re: more on forged pistons, Philip HS, Fri, 16 Apr 2004 14:08:23
  • Re: Saab's not gonna cover it!!, serendipity, Fri, 16 Apr 2004 07:47:15
  • I should keep my thoughts to my self but, Brad, Fri, 16 Apr 2004 06:02:11
    • More things I should not say, Brad, Fri, 16 Apr 2004 09:21:30
      • Re: More things I should not say, TERRY, Fri, 16 Apr 2004 11:57:48
      • Re: More things I should not say, Dean, Fri, 16 Apr 2004 09:33:04
        • Re: More things I should not say, Brad, Fri, 16 Apr 2004 10:01:11
          • Dean, I posted some info about my IC experiences, Vigge, Fri, 16 Apr 2004 10:50:14
          • Re: More things I should not say, jak , Fri, 16 Apr 2004 10:40:47
    • dont blame SQR, nickR, Fri, 16 Apr 2004 08:37:01
    • Most ecu tuner do cover the cost, ckpaden, Fri, 16 Apr 2004 08:02:05
      • Chipcenter offers gaurantee, nickR, Fri, 16 Apr 2004 08:34:31
    • I'm not buying SQR..., DaveD, Fri, 16 Apr 2004 07:56:49
      • I just had it on a dyno & A/F was 12:1 to redline, Steve88SiS, Fri, 16 Apr 2004 17:35:20
      • I met frank & watched while....., jak , Fri, 16 Apr 2004 09:38:22
      • SQR is awesome, period., TERRY, Fri, 16 Apr 2004 09:00:02
        • Some clarification, Vigge, Fri, 16 Apr 2004 12:43:50
          • Re: Some clarification, TERRY, Fri, 16 Apr 2004 13:22:26
            • Re: Some clarification, Vigge, Fri, 16 Apr 2004 14:20:09
              • Re: Some clarification, TERRY, Fri, 16 Apr 2004 16:02:44
                • Re: Some clarification, Vigge, Sat, 17 Apr 2004 00:25:55
      • Re: I'm not buying SQR..., ckpaden, Fri, 16 Apr 2004 08:03:56
        • Re: I'm not buying SQR..., ed smith, Fri, 16 Apr 2004 17:27:20
  • You haven't asked, but I have to disagree with your, MichaelG, Thu, 15 Apr 2004 19:30:51
    • SAAB does watch these BBs..., WASSAAB, Fri, 16 Apr 2004 11:09:40
      • Re: SAAB does watch these BBs..., Harpua, Sun, 18 Apr 2004 11:31:09
        • Harpua, who is that?? Funny regardless. :o) n/m, TERRY, Sun, 18 Apr 2004 21:15:59
          • Re: Harpua, who is that?? Funny regardless. :o) n/m, Harpua, Sun, 18 Apr 2004 21:23:44
    • Re: You haven't asked, but I have to disagree with your, john, Thu, 15 Apr 2004 19:46:45
  • Arbitration?, ckpaden, Thu, 15 Apr 2004 19:19:40
    • careful here...., MichaelG, Thu, 15 Apr 2004 19:33:17
      • Eagle talon, ckpaden, Fri, 16 Apr 2004 07:58:20
  • Re: Saab's not gonna cover it!!, steve, Thu, 15 Apr 2004 18:47:36
    • I understand Steve's frustration.....(longish), TERRY, Thu, 15 Apr 2004 20:34:00
      • You're assuming that there wasn't a glitch, AdamB , Fri, 16 Apr 2004 02:42:52
        • Re: You're assuming that there wasn't a glitch, TERRY, Fri, 16 Apr 2004 09:09:02
        • Re: You're assuming that there wasn't a glitch, Vigge, Fri, 16 Apr 2004 05:27:34 <-- Viewing This Message
          • I stand corrected, AdamB , Sat, 17 Apr 2004 03:14:00
          • GOOD PIC !!!!!This is EXACTLY what I was talking about!, TERRY, Fri, 16 Apr 2004 08:48:36
          • Re: You're assuming that there wasn't a glitch, BrianS, Fri, 16 Apr 2004 07:18:47
      • come to think of it, steveC, Thu, 15 Apr 2004 22:18:43
  • Re: Saab's not gonna cover it!!, TERRY, Thu, 15 Apr 2004 16:39:09
  • that too bad:-(...however, steveC, Thu, 15 Apr 2004 16:34:07
  • I feel for you, nickR, Thu, 15 Apr 2004 16:05:34
    • ...that was "financial" damage I was referring to, nickR, Thu, 15 Apr 2004 16:06:34
  • Not to rub salt in your wound..., AdamB , Thu, 15 Apr 2004 15:44:57
  • sorry to hear the bad news, but I wouldn't blame Saab, Chad B, Thu, 15 Apr 2004 15:20:19
    • Re: sorry to hear the bad news, but I wouldn't blame Saab, ed smith, Thu, 15 Apr 2004 17:24:32

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