ADU Cam Pulley with 7A Cams - timing setup?

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  • afen
    S2Forum Enthusiast
    • Aug 2011
    • 112
    • Country: Norway

    #1

    ADU Cam Pulley with 7A Cams - timing setup?

    Hello!

    I have a AAN block/head with ADU cam pulley and 7A cams. I see that the ADU timing is supposed to have the cam pulley one tooth off, but does this still apply with 7A cams? I've tried searching the forums but I haven't found an answer for this combination.

    I also have an intermittent problem with starting the engine. Sometimes it takes a while to fire, and when it does the revs build slowly until correct idle rpms. Other times it fires right up like normal. Bad contact on cam or flywheel sensor maybe?
  • UrS4boy
    S2Forum Obsessed
    • Feb 2006
    • 11859
    • Country: Canada

    #2
    The shutter window on an ADU 105B cam pulley is shifted something like 10 degrees compared to an AAN shutter window/pulley. On that basis, setting up the 7A cams probably has to be the same as the ADU cams. Otherwise, use the AAN (or ABY) shutter wheel and set up 7A cams as normal (AAN/ABY cams). (EDIT: See second reply. Go with the AAN/ABY shutter wheel with the 7A cams).

    AAN/ABY shutter wheel:



    ADU shutter wheel:



    AAN/ABY on left, ADU on right

    Last edited by UrS4boy; 18 December 2014, 16:40.
    RS2'd 93 UrS4 5 spd sedan
    94 UrS4 V8 6 spd manual avant

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    • UrS4boy
      S2Forum Obsessed
      • Feb 2006
      • 11859
      • Country: Canada

      #3
      I take my first suggestion back. The 7A exhaust cam lobes have not been ground 10 degrees off center like the ADU exhaust cam. As a result, I think the best set-up is to run the 7A cams with an AAN (or ABY) exhaust cam sprocket and shutter wheel, set up as normal AAN or ABY.
      RS2'd 93 UrS4 5 spd sedan
      94 UrS4 V8 6 spd manual avant

      Comment

      • Laaf
        S2Forum Addict
        • Oct 2010
        • 275
        • Country: Finland

        #4
        Originally posted by afen
        Hello!

        I have a AAN block/head with ADU cam pulley and 7A cams. I see that the ADU timing is supposed to have the cam pulley one tooth off, but does this still apply with 7A cams? I've tried searching the forums but I haven't found an answer for this combination.

        I also have an intermittent problem with starting the engine. Sometimes it takes a while to fire, and when it does the revs build slowly until correct idle rpms. Other times it fires right up like normal. Bad contact on cam or flywheel sensor maybe?
        I had also a ADU cam pulley installed with AAN cams when I bought the car. I experienced also it sometimes being hard getting the car started. After changing the pulley for a a adjustable with the 7A cams I havent had the problem. I only bought the adjustable one if I have to tune the cam setup some time. Now I set the engine at TDC and setup the camwheel accordingly.

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