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  • #16
    So what exactly is the deal with using the TT pistons and rods in our Z31's? is there a difference between the 84-3/87 non W series and W series? If you use the TT pistons and rods what changes in the specs of the engine? compression?, stroke? I've got a block that I would like to hot tank and rebuild into a turbo so I need to know before I spend lots of money on pistons and rods.
    Its all fun till you hit the doggie and do an endo into the wall.

    One willing to take his own life into his hands,
    Will not hesitate to take the lives of others.

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    • #17
      Zen wrote: So what exactly is the deal with using the TT pistons and rods in our Z31's? is there a difference between the 84-3/87 non W series and W series? If you use the TT pistons and rods what changes in the specs of the engine? compression?, stroke? I've got a block that I would like to hot tank and rebuild into a turbo so I need to know before I spend lots of money on pistons and rods.

      TT rods fit on the z31 crank. Only TT pistons fit the TT rods. TT pistons bring your compression to roughly 8.1:1 Stroke of 3.27" or 83mm does not change. Bore of 3.43" or 87mm does not change UNLESS
      you are doing forged pistons. Then you bore .020"-generally, depending on manufacturers recomendations.

      Non w series rods are not full floating wrist pins and have either a larger or smaller wrist pin. W series DO HAVE a full floating wrist pin and are either larger or smaller.
      85 Z31 6.0 LSX turbo 766whp/792wtq
      04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

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      • #18
        Thanks, so getting a set of TT forged pistons .20 over, TT Rods, use the stock crank and I'm set to go on my build.
        Its all fun till you hit the doggie and do an endo into the wall.

        One willing to take his own life into his hands,
        Will not hesitate to take the lives of others.

        Comment


        • #19
          Zen wrote: Thanks, so getting a set of TT forged pistons .20 over, TT Rods, use the stock crank and I'm set to go on my build.
          You dont get the pistons .020" over. Thats how much you have to bore the block due to the expansion of a forged piston when it heats up Depending on the silicon content, but we wont get into that.
          85 Z31 6.0 LSX turbo 766whp/792wtq
          04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

          Comment


          • #20
            there isn't a piston in existance that will expand 20 thousandths.. You won't see anymore than 5 thou expansion on a low silicon forged piston.

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            • #21
              defrag010 wrote: there isn't a piston in existance that will expand 20 thousandths.. You won't see anymore than 5 thou expansion on a low silicon forged piston.
              That is a bold statement and is also false.

              The bigger the piston is the more expansion there will be. Yes there are pistons in lots of things that have a diameter greater than that of which you stand in height. I think what you mean is, in normal situations, they dont TYPICALLY expand more than .005"

              Even if a VG30 low silicon forged piston only expands .005" that doesnt mean that you dont bore your block out .020" Its not my recomendations either, its the piston manufacturers recomendations.
              85 Z31 6.0 LSX turbo 766whp/792wtq
              04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

              Comment


              • #22
                I'm not talking about train engines with 6ft diameter pistons, I'm talking about real world dimensions that are used in car engines --- specifically a VG30.

                I've honed and assembled a buttload of shortblocks with forged pistons from diamond, JE, wiseco, mahle, speed pro, keith black, jun, arias, and many more... all the way from 75mm honda d16's to 4.625" bore merlin bbc's.. and have never seen a manufacturer spec sheet that says anything over 5 thousandths clearance at the skirt. How many real world people with car engines have over 4.5" bore?

                .020" clearance in a VG30 would not only slap like a diesel and gall the piston skirts/bores severely, but it would burn so much oil due to large ring gap/low ring pressure and lose so much compression to blowby that the engine would barely run. If a VG30 forged piston expands 5 thousandths, you hone the block out to provide about 5.5 to 6 thousandths clearance... not twenty.. ask any machinist, and I'll bet you 1000$ that any piston manufactuer's VG30 low silicon forged piston isn't reccomended for over .005" skirt to wall clearance.

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                • #23
                  Ok, now Im really confused, which is normal ops: :roll: me being a newbe to automachinics in general. From those that I've talked to it was recomended that when rebuilding an old motor like these you should have the block bored .020 over If Needed and order pistons .020 over. I see they sell stock cast pistons that way in black dragon mag. Why would you not order your forged pistons the same way?

                  So if what Defrag is saying then I should see about having the block bored .005 and use the stock size TT forged pistons???
                  That leaves me to believe the stock TT pistons are larger that the stock cast z31 pistons? :?:
                  Its all fun till you hit the doggie and do an endo into the wall.

                  One willing to take his own life into his hands,
                  Will not hesitate to take the lives of others.

                  Comment


                  • #24
                    I agree that this statement is incorrect.

                    SATAN wrote:
                    You dont get the pistons .020" over. Thats how much you have to bore the block due to the expansion of a forged piston when it heats up Depending on the silicon content, but we wont get into that.
                    The pistons are actually .020" larger than stock. However, you need to ask your piston manufacturer what clearance you need for the rings. It'll be different for your power goals, nitrous, turbo, n/a......as they heat up and expand differently.
                    1987 300ZX Turbo - http://www.z31performance.com/forum/vie ... php?t=3114
                    2001 Tiburon Turbo 60-1 270whp/268tq

                    No cupholders? Where am I gonna put my beer????

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                    • #25
                      :P

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                      • #26
                        88sinZ wrote: Floating pins from the 88-89 engines are the same as the pins for the z32 engines.
                        This is False Z32 pins are 1mm bigger

                        Engloid needs to update or Delete that page so it stops spreading miss information
                        2005 whore magnet

                        Comment


                        • #27
                          Defrag, Calm down man, I belive I agreed with you and said " In normal conditions".

                          Yes you are correct I dont know what I was thinking when I wrote " The piston is not .020" larger" ????? The JE pistons Which are what I run ARE 87.5mm. Yes you are also correct on the side wall clearances JE recomends NO smaller that .0022-.0028"
                          85 Z31 6.0 LSX turbo 766whp/792wtq
                          04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                          Comment


                          • #28
                            [quote]Evil Z31 wrote: I agree that this statement is incorrect.

                            Originally posted by SATAN
                            You dont get the pistons .020" over. Thats how much you have to bore the block due to the expansion of a forged piston when it heats up Depending on the silicon content, but we wont get into that.
                            The pistons are actually .020" larger than stock. However, you need to ask your piston manufacturer what clearance you need for the rings. It'll be different for your power goals, nitrous, turbo, n/a......as they heat up and expand differently.
                            Yes, you are correct, I dont know what I was thinking when I wrote that.
                            85 Z31 6.0 LSX turbo 766whp/792wtq
                            04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                            Comment


                            • #29
                              [quote]SteveZ31 wrote:
                              Originally posted by 88sinZ
                              Floating pins from the 88-89 engines are the same as the pins for the z32 engines.
                              Originally posted by 88sinZ
                              This is False Z32 pins are 1mm bigger

                              Engloid needs to update or Delete that page so it stops spreading miss information
                              Yes Steve, you are correct. I just measured both the other day. My JE piston that I have sitting on my book case measures 22mm and the stock W series piston we pulled out of jonny's car measures 21mm
                              85 Z31 6.0 LSX turbo 766whp/792wtq
                              04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                              Comment


                              • #30
                                NO, I'm correct!!


                                wait..... I didn't say anything! ops:

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