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no compression

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by detailer03, Apr 5, 2004.

  1. detailer03

    detailer03 1/2 ton status

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    Ok, a friend, not me, really, overhauled the engine in his 90. 5.7 TBI. He has no compression. Things I told him to check, see if the valves are too tight/loose, I inquired as to whether the timing chain and gears were installed correctly, is the cam in right. What else? What could he have missed?
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Did he install piston rings and head gaskets? /forums/images/graemlins/rotfl.gif
     
  3. detailer03

    detailer03 1/2 ton status

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    He said yes. I did ask him if he staggerd the piston rings, he said yes.
     
  4. fjleiter

    fjleiter 1/2 ton status

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    I remember in Auto Tech back in high school (did the 2 year trade school program), number one mistake that first year kids did when rebuilding an engine was having the rings all lined up instead of staggered. Of course I saw more than one get bolted back together without rings as well. Biggest list of mistakes was
    1) Cranking down all the rockers till "they were tight"
    2) Cam off 180 degrees
    3) rings installed improperly
    4) connecting rods/maincaps over tightened
    (had one engine that two of us were unable to turn over by hand with no plugs in it, turned out the kid had used a 1/2" air ratchet to assemble the bottom end, out sick for a few weeks, he figured he could "catch up" and save his grade. Couldn't believe he did it without snapping bolts. Had to use a 24" breaker bar and all my weight to get the main caps off).
    5) distributor installed improperly or plug wires routed incorrectly
    6) Vacuum leaks (you name it)

    My guess with zero compression would be he cranked all the rockers down and opened all the valves up, even with rings installed wrong he would have some compression.
     
  5. highrider_44s

    highrider_44s 1/2 ton status

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    did he use a hydrolic lifter cam? i'd guess he set the valves to tight when he got oil preasure the hyd lifters pumped up held all the valvs open /forums/images/graemlins/waytogo.gif
     
  6. fortcollinsram

    fortcollinsram 1/2 ton status

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    My bet is the valves. loosen em up a bit. Even if he focked up the rings, it would have some compression

    Chris
     
  7. detailer03

    detailer03 1/2 ton status

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    I will check the rockers with him after work. I say they are too tight also, he says no.
    We will see.

    Thanks
     
  8. jeffro

    jeffro 1/2 ton status

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    Make sure your schrader valve in the end of the compression tester is good.
     

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