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1997 3.1 cyl compression results

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  • 1997 3.1 cyl compression results

    My motor did overheat badly this winter and had antifreeze in the cylinders. I had to have it towed. Cylinders 3&5 are 30psi and 50psi. Cylinders 1,2,4,& 6 are 135 psi.. The intake gaskets showed no sign of leakage on this motor with over 250,000 miles and I'm the original owner. I did however remove the factory antifreeze at 30,000 miles. I'll be doing a head gasket job now and i'll have the heads checked for flatness, cracks, and resurfaced. Have no time to reseat the valves but new valve seals would not take long to do. Any other suggestions for now from the members are welcome.....Tom

  • #2
    did you try a leakdown test? maybe its the rings that are worn?
    Mike 60degree addict.
    Beretta 96 3500 - 14.981@ 93.32
    65MM thorttle body, Crank trigger 97 venture ECM and Dhp powrTuner


    • #3
      No. I assumed if two cylinders side by side showed a low compression test, then it could be a head gasket. How do i perform a leak down test to rule out a bad head gasket?......Tom


      • #4
        A leak-down test requires an air compressor and a special tool. You basically keep the crank from spinning while you pressurize a cylinder at TDC. The tool has two gauges, one to read pressure going in and the other measures pressure that's escaping out.
        1995 Grand Am SE


        • #5
          Guys there was antifreeze in his cylinders, he blew a gasket. No need for a leak down test.

          Also if your having the heads surfaced why not have the machine shop reseat the vavles while they are there... it will take no longer, and ensure your valves are sealed before re-assy.

          Doesn't make sense to skip over something that easy when your that far in.

          Got Lope?
          3500 Build, Comp XFI Cam 218/230 .050 dur .570/.568 lift 113LSA
          Fully Balanced, Ported, 3 Angle Valve Job, 65mm TCE TB, S&S Headers.
          Stage-1 Raybestos/Alto 4t60e-HD, EP LSD, 3.69FDR
          12.61@105 Epping NH Oct 2015 Nitrous 100shot (melted plugs) 13.58@98.8 N/A 3200LBS


          • #6
            Coolant was only in cyl. 3 & 5 that's my head gasket assumtion.....I'll let the machine shop evaluate my heads for resurface and regrind (good point) and hope their not cracked or need to much taken off the surface, then as an option I'll also go price out a pair of low mileage used M code 3.1 roller heads at the salvage yard as my heads got really hot that day it overheated....Tom


            • #7
              I have a set of M code heads that were completly rebuilt that I never used. I had them rebuilt and then change my mind and got a 3400. The head don't have rockers on them now, but have the notches for roller fulcrum rocker. I do have several sets of rollers if you need them. Let me know if you have any interest.