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Compression test results on my 1988 maroon NA2T w/VG30ET

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  • Compression test results on my 1988 maroon NA2T w/VG30ET

    I decided to run a compression test on the stock 8.3:1 engine that's in my 1988 maroon NA2T. It's the same engine that was originally in my SS, then in my black 1988 Turbo Z that got totalled.

    Cylinder 1: 165 psi..................cylinder 2: 125 psi
    cylinder 3: 170psi...................cylinder 4: 172 psi
    cylinder 5: 170 psi..................cylinder 6: 172 psi

    Then I added some oil to cylinder # 2 and retested the compression and it had 170 psi.I guess the rings are about to go on that piston. Pretty good compression on the old engine except for cyl #2.
    Do you think I should take it easy with the boost or do you think it'll still hold 15 psi without going south?
    Shiro #443


  • #2
    try the suck-in seafoam, you shoot it in the vac port while its running, or shoot it down the spark plug hole after you turned it off

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    • #3
      If it's anything like my 88T engine, it will work great for thousands of miles of abuse.... just be a little smokey and down on power.

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      • #4
        So keep pushing it at 15 psi or go for more? :twisted:
        Shiro #443

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        • #5
          Rick88ss wrote: So keep pushing it at 15 psi or go for more? :twisted:
          It'll smoke more, but yeah, go for it.

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          • #6
            My compression is worse than that and my blowby is worse than what i saw on your dyno run, i POUR out smoke through the drivers side breather and i know i have alot coming out of the passenger side breather. I still boost the hell out of it, 18psi daily. I only got 4K out of this motor so far, id be surprised if i get to 10K on it though unfortunately. And i run very little timing which is a bummer

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            • #7
              Rick88ss wrote: I decided to run a compression test on the stock 8.3:1 engine that's in my 1988 maroon NA2T. It's the same engine that was originally in my SS, then in my black 1988 Turbo Z that got totalled.

              Cylinder 1: 165 psi..................cylinder 2: 125 psi
              cylinder 3: 170psi...................cylinder 4: 172 psi
              cylinder 5: 170 psi..................cylinder 6: 172 psi

              Then I added some oil to cylinder # 2 and retested the compression and it had 170 psi.I guess the rings are about to go on that piston. Pretty good compression on the old engine except for cyl #2.
              Do you think I should take it easy with the boost or do you think it'll still hold 15 psi without going south?
              How many miles on it?
              http://www.vgpowered.com
              Bridging the gap between VG communities...

              Z shirts and more http://www.cafepress.com/zcargifts

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              • #8
                Rick88ss wrote: I decided to run a compression test on the stock 8.3:1 engine that's in my 1988 maroon NA2T. It's the same engine that was originally in my SS, then in my black 1988 Turbo Z that got totalled.

                Cylinder 1: 165 psi..................cylinder 2: 125 psi
                cylinder 3: 170psi...................cylinder 4: 172 psi
                cylinder 5: 170 psi..................cylinder 6: 172 psi

                Then I added some oil to cylinder # 2 and retested the compression and it had 170 psi.I guess the rings are about to go on that piston. Pretty good compression on the old engine except for cyl #2.
                Do you think I should take it easy with the boost or do you think it'll still hold 15 psi without going south?
                :lol:
                Did I call that or what?
                Do I get a cookie?
                I am here to help...

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                • #9
                  I'm pretty sure the FSM states that compression above 128 PSI is considered acceptable so you are pretty close at least.

                  1987 Nissan 300ZX Turbo (Budget Supercar)
                  1987 Nissan 200SX SE (Old School FR)
                  1994 Nissan Sentra SE-R (Balls To The Wall Track Car)
                  2000 Nissan Maxima SE (Daily Driver)
                  2006 Scion tC (Wife Whip)

                  In an ideal world I would have all ten fingers on my left hand, so my right hand could just be a fist for punching.

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                  • #10
                    Taris Blue wrote: I'm pretty sure the FSM states that compression above 128 PSI is considered acceptable so you are pretty close at least.
                    Yeah it also says that you can run the gap on your rings up to .039" which is insainly big. but they consider that acceptable.
                    85 Z31 6.0 LSX turbo 766whp/792wtq
                    04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

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                    • #11
                      Taris Blue wrote: I'm pretty sure the FSM states that compression above 128 PSI is considered acceptable so you are pretty close at least.
                      they also say maximum 14psi variation, which he's tripled

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                      • #12
                        blah blah blah, boost the shit out of it! If it dies, so what you can get 10 more in the junkyard for $100 a piece. Get that thing back on the dyno at 22psi!!

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                        • #13
                          roastin300 wrote: blah blah blah, boost the shit out of it! If it dies, so what you can get 10 more in the junkyard for $100 a piece. Get that thing back on the dyno at 22psi!!
                          Funny how boost can make up for compression....

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                          • #14
                            Jason84NA2T wrote: Funny how boost can make up for compression....
                            Its easier and cheaper to turn a knob than to swap/rebuild a engine.
                            1986 Current build
                            HX35/40 60mm wheel,480cc injectors,nistune, spearco 2-221,6 puck,walbro fp,solid cross and diff,jason motor mounts,poly everywhere else.

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