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Engine Compression

Discussion in '40- & 55-Series Tech' started by ClemsonCruiser, Mar 13, 2004.

  1. ClemsonCruiser

    ClemsonCruiser

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    Okay, I have psoted on here several times about my engine burnig oil, and wether it needs a rebuild or maybe new rings........ So I have done the compression test wet and dry, here are the numbers;

    dry: 155 132 132 147 150 165
    wet: 170 150 142 152 160 175

    Is there any definte problem, such as rings, that can be spotted by these numbers. Also to add to this I tested the compression, just dry, a week ago and got these numbers:
    143 125 115 130 130 148, obviously these numbers are lower than the numbers I got today in all cylinders by an average of 15 psi. Is it normal to see a jump like this in a week, I did add a container of engine restorer this week.
    I have already come to the conclusion that I need new vavle seals, because my engine smokes badly after long dowhill runs with engine breaking. Any input you have to what I need to do to fix my engine is apreciated.

    Thanks
    JP
     
  2. godzilla

    godzilla

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    Why not just put new rings and pistons in and do a valve job. I'm sure your engine has more than 100,000 on it.
     
  3. godzilla

    godzilla

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    Foot in mouth diease. I saw that you have it listed as 52,000. If your truck sat for a long time before you got it, it may need new valve stem seals.
     
  4. jim45r

    jim45r

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    Well, even though #2 & #3 are lower than the others, the compression looks pretty decent. I'd say replacing the valve seals will end your smoking. I've only done it with head off; but it can be done without pulling the head. If you're not an experienced wrencher and you want to try it, you should really study up on it - there are tricks to holding the valve in place while you take the springs off, etc. There are good resources on the web - you don't need to look specifically for land cruiser info - the F and 2F heads use really common standard designs, right out of auto shop 101. If you don't feel confident but do have some dough, take the head off and take it in to a automotive machine shop for a valve job. It'll take ~$80 in gaskets and the valve job can run anywhere from $200 to $500 depending on where you live and who you know. That's this shade tree mechanic's opinion, for what it's worth.