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compression

  1. L36 and L67 Compression Ratio/Octane?

    Fuel System
    What I'm wondering, is why is it that the L36 with 9.4:1 compression requires 87 minimum octane, whereas the L67 with 8.6:1 compression requires 91 octane minimum? If engines with higher compression require higher octane, then why does the L36 require a lower minimum octane? And also, why the...
  2. Valve train hell need a genius

    Cams/Heads/Valvetrain
    Bought an 02 GP 3800 that threw a rod through the block. Bought a core and rebuilt it. Here is the problem: I have 175lbs compression on all cylinders except #1 and #2 after cranking for a minute. If I loosen the rocker arms, I get 175 for as long as the batt holds out. I have checked lash and...
  3. Cylinders leaking 40% compression after rebuild.

    Cams/Heads/Valvetrain
    Hey guys, I'm rebuilding my L67 because it was losing about 40% compression in a leak down test and was running really rough. I re-ringed the pistons but didn't re-bore because the cylinders looked good with no ridge at the top and the factory cross-hatch pattern was still visible (did a light...
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