AAN head on 7a block?

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  • mbcouple
    S2Forum Fanatic
    • Sep 2003
    • 78

    #1

    AAN head on 7a block?

    I need a new block for my aan head. A local guy has a 7a block lying around. If i transfer the rotating assembly from the aan block to the 7a block, will the 7a bolt right up to the aan head? Are the oil ports missing for the turbo that will have to be tapped?
    Thanks
    Hans
  • Doug_RS2
    S2Forum Possessed
    • Jul 2003
    • 3847
    • Home: Scotland Current: England

    #2
    7A is 82.5mm bore, AAN is 81mm - You will need at least new pistons and this is assuming the gaps between the cylinders are good enough for a turbo application.

    Don't know about the oil squirters.
    S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

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    • mbcouple
      S2Forum Fanatic
      • Sep 2003
      • 78

      #3
      Thanks, its been a while since i worked with a 7a. What block out there can i use? I have a good rotating assembly, just a block beyond repair.
      Thanks
      Hans

      Comment

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

        #4
        I think you are limited to the AAN, ABY, ADU or the 3B (but the 3B needs mounting holes for the cam position sensor). There might be others - I am not sure though - some of the part gurus will know more.
        S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

        Comment

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

          #5
          Errm. Ignore that cam position sensor stuff. It's in the head, not block.
          3B block lacks the newer style cambelt tensioner holes so you would have to use 3B timing stuff (oil pump with static relay roller, water pump and timing belt covers).
          And about the 82,5mm bore. I would never use it on a turbo engine.
          -

          Comment

          • mcandmar
            S2Forum Zealot
            • Apr 2004
            • 5118
            • Country: Ireland

            #6
            Cant answer your question buy i tried to find somebody who had put a turbo head onto a 7A block and nobody has. Biggest problem is the Compression ratio due to different pistons, and the larger bore. You would have to get pistons made so it would be cheaper to buy a used 2.2 block and work from there.

            Oil squirters are on the 7A block too. To the best of my knowlage turbo oil ways tap into the block the filter screws into, also feeds oil cooler etc which a 7A does not have, the oil filter screws directly onto the block on a 7A.

            Originally posted by mbcouple
            I need a new block for my aan head. A local guy has a 7a block lying around. If i transfer the rotating assembly from the aan block to the 7a block, will the 7a bolt right up to the aan head? Are the oil ports missing for the turbo that will have to be tapped?
            Thanks
            Hans
            91CQ20v - Gone to a new home
            93UR-S4 - The Magic Carpet
            94S2Bus - The Emerald Express

            Comment

            • mbcouple
              S2Forum Fanatic
              • Sep 2003
              • 78

              #7
              So is there a cheap block that i can use, or do i just have to bite the bullet and buy another complete aan block? They are expensive here in the US about $1000.
              Thanks
              Hans

              Comment

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

                #8
                Originally posted by porkkis
                Errm. Ignore that cam position sensor stuff. It's in the head, not block.
                doh
                S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

                Comment

                • RSCoupe
                  S2Forum Enthusiast
                  • Dec 2003
                  • 120
                  • Country: United States

                  #9
                  The 7A block can be used. I'm using the 7A block and head on my project. I will even bore the block to 83mm. Javad Shadzi here in the states has done this and the car is running fine (with exception of a mistake his machine shop made while assembling the head). He will be pushing 550-600hp.

                  Granted, he used stronger rods, custom pistons, copper head gasket, etc. Not much stock when all is said and done.

                  Mine will be very similar to his (different EM, IM, turbo). I am also shooting for 550-600hp. It is just taking a lot longer for me to do, but at least I can see from his project that mine should work.
                  Mark Siggelkow

                  '90 CQ 20vT - NASA GTS-5 (R.I.P.)
                  '90 CQ-R - NASA GTS-4/5
                  '00 A4 1.8TQMS (Wife's Daily Driver)
                  '12 TT-RS (Wife's new DD, on order for May European delivery)
                  '62 Porsche 356B (another race car)
                  '03 Kawasaki Z1000 (toy)

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

                    #10
                    Originally posted by RSCoupe
                    He will be pushing 550-600hp.
                    But not for long
                    -

                    Comment

                    • caterpillar
                      S2Forum Fiend
                      • Jun 2004
                      • 2480

                      #11
                      in the germany they sell turbokit for the 7a's ! you may use any block you want.the only you have to do:the return of the turbo oil,you have to drill it up.it is marked on the block.if you want more than 380hp and 550NM,you need to change the rods,to H-profils ditto.......

                      Comment

                      • auditude
                        S2Forum Addict
                        • Aug 2003
                        • 407
                        • Country: United States

                        #12
                        Originally posted by porkkis
                        But not for long
                        Does that mean he's going to crank it up for even more power, or that it's going to break before long? I could interpret that either way, or even both!
                        Kenneth
                        1990 Coupe quattro
                        1991 200q20v x 2
                        1985 4ksq 20vt project
                        1986 Coupe GT 10vt project
                        2006 Honda Ridgeline
                        1998 Honda VFR800FI

                        Comment

                        • auditude
                          S2Forum Addict
                          • Aug 2003
                          • 407
                          • Country: United States

                          #13
                          Originally posted by caterpillar
                          in the germany they sell turbokit for the 7a's ! you may use any block you want.the only you have to do:the return of the turbo oil,you have to drill it up.it is marked on the block.if you want more than 380hp and 550NM,you need to change the rods,to H-profils ditto.......
                          Does this company have a website? I'm curious about this offering.
                          Kenneth
                          1990 Coupe quattro
                          1991 200q20v x 2
                          1985 4ksq 20vt project
                          1986 Coupe GT 10vt project
                          2006 Honda Ridgeline
                          1998 Honda VFR800FI

                          Comment

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