Valves to piston gap

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  • Doug_RS2
    S2Forum Possessed
    • Jul 2003
    • 3847
    • Home: Scotland Current: England

    #1

    Valves to piston gap

    What is this gap?

    What is the gap from the top of the piston to the top of the block.

    I'm starting to worry that my valves are going to be too close to the pistons now the head has been off 3 times(i know off) in it's life.
    S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8
  • Audi Parts Guru
    S2Forum Extremist
    • Jul 2003
    • 1317
    • Home: England Current: United Kingdom

    #2
    What makes you think that your valves will touch the piston Doug ?
    S2 Avant......fully loaded :rock: :bow: Slipper Wagons Rule !!!!!

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    • Doug_RS2
      S2Forum Possessed
      • Jul 2003
      • 3847
      • Home: Scotland Current: England

      #3
      Someone told me that they got the valves machined the same amount they skimmed the head, to stop the valves touching the pistons - this was becasue it was an S2

      I'm just getting paranoid about too much being taken off the head.
      S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

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      • Audi Parts Guru
        S2Forum Extremist
        • Jul 2003
        • 1317
        • Home: England Current: United Kingdom

        #4
        How much did you have taken off the head then ?
        S2 Avant......fully loaded :rock: :bow: Slipper Wagons Rule !!!!!

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        • SteveH
          Super Moderator
          • Jul 2003
          • 4460
          • Country: United Kingdom

          #5
          Doug, I don't think it's going to be an issue, unless lots of material has been removed from the head during skimming. I've only heard of problems with the hydraulic lifters if the valve seats are cut back too far. You should find some info in the 3B engine manual. I'm in the same position as you, my head has been on and off a few times now
          91 Modded 3B
          14 A6 Avant Black Edition

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          • Doug_RS2
            S2Forum Possessed
            • Jul 2003
            • 3847
            • Home: Scotland Current: England

            #6
            The head had been off before I bought the car. It was off a few weeks ago and had 8 thou skimmed off. Now it is off again and although it hasn't ran it was torqued up, so could well need skimmed again.
            S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

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            • SteveH
              Super Moderator
              • Jul 2003
              • 4460
              • Country: United Kingdom

              #7
              8 Thou! Ouch, that is a lot to have removed. Fingers crossed you're still within limits and it doesn't need doing again.
              91 Modded 3B
              14 A6 Avant Black Edition

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              • Mihnea
                S2Forum Extremist
                • Jul 2003
                • 1288
                • Home: Belgium Current: United Kingdom

                #8
                Originally posted by Doug_RS2
                The head had been off before I bought the car. It was off a few weeks ago and had 8 thou skimmed off. Now it is off again and although it hasn't ran it was torqued up, so could well need skimmed again.

                Doug, why the heck is it off again?? What happened ?

                Mihnea
                '98 Silver Grey 2.7T S4, dual 2.75" turbo back exhaust with no cats, FMIC, BIG injectors, 10 Bar motorsport fuel pump, modded RS4 turbos, tubular exhaust manifolds, custom intakes, RS4 MAF, Bilstein PSS9, H&R ARBs, 19" BBS CH, custom remap, 511 BHP/505ft-lbs

                www.MRCTuning.com
                info@MRCTuning.com
                Workshop Directions

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                • porkkis
                  S2Forum Extremist
                  • Aug 2003
                  • 1994
                  • Country: Finland

                  #9
                  Doug, don't skim it now. Totally unnecessary.
                  -

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                  • Doug_RS2
                    S2Forum Possessed
                    • Jul 2003
                    • 3847
                    • Home: Scotland Current: England

                    #10
                    Originally posted by Mihnea
                    Doug, why the heck is it off again?? What happened ?
                    Because of the pic - the feckers put the helicoil in upside down so the broken tang would not let the spark plug go in - I'm ****** off cause I didn't check it until I had everything back on - and they are getting charged for yet another set of bolts etc. Feckers.

                    Mihnea - still no chips You need to move over here so the mail service is better
                    Attached Files
                    S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

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                    • Doug_RS2
                      S2Forum Possessed
                      • Jul 2003
                      • 3847
                      • Home: Scotland Current: England

                      #11
                      Originally posted by porkkis
                      Doug, don't skim it now. Totally unnecessary.
                      Why not - the head bolts were torqued up - I'm getting another set of head bolts.
                      S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

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                      • Audi Parts Guru
                        S2Forum Extremist
                        • Jul 2003
                        • 1317
                        • Home: England Current: United Kingdom

                        #12
                        Originally posted by Doug_RS2
                        Mihnea - still no chips You need to move over here so the mail service is better
                        S2 Avant......fully loaded :rock: :bow: Slipper Wagons Rule !!!!!

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                        • desmo888
                          S2Forum Addict
                          • Oct 2003
                          • 390
                          • Country: United States

                          #13
                          Worried?
                          CHECK IT!!:eek2:
                          It is easy. Get yourself some Play-Do.
                          Put it on top the piston in the area where the valves would touch.
                          put the head on with old bolts and old gasket and torque to specs.
                          Rotate the engine one full rotation slowly.
                          Pull off the head
                          Slice the Play-Do across the impression and measure the thickness.
                          I can't remember for sure (I will check for you) but I think you should have a minimum of 0.030"
                          A bit of work but a huge POM (Piece of Mind).
                          This is very common when doing hi performance V8's with high lift cams.
                          Dave K.
                          USA
                          1991 e//S2 (home built S2 - the only way to get one in USA!)
                          2001 S4

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                          • desmo888
                            S2Forum Addict
                            • Oct 2003
                            • 390
                            • Country: United States

                            #14
                            Originally posted by SteveH
                            I've only heard of problems with the hydraulic lifters if the valve seats are cut back too far. (
                            Valve seat cutting will not affect piston to valve clearance.
                            Block decking, head shaving and high lift cams will!
                            Dave K.
                            USA
                            1991 e//S2 (home built S2 - the only way to get one in USA!)
                            2001 S4

                            Comment

                            • newsh
                              S2Forum Obsessed
                              • Aug 2003
                              • 16226
                              • Country: United Kingdom

                              #15
                              Originally posted by Doug_RS2
                              Why not - the head bolts were torqued up - I'm getting another set of head bolts.
                              I think he means no need to skim the head, it hasn't been hot, but you could check it with a straight edge, it shouldn't be bent after torqueing it down once. Must use new bolts though.

                              IMHO you should never "torque to spec" with old bolts, they are already stretched and may crack the block, I've seen it happen on Golf motors.

                              Nipping it down to 50% on the old gasket should be enough to check clearances though, don't you think?

                              S2 Coupe 3B Project


                              Ur quattro restoration

                              S2 Avant

                              Boost is the new rock and roll!
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