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Compression ?

Discussion in '40- & 55-Series Tech' started by petescoffee, Oct 28, 2003.

  1. petescoffee

    petescoffee

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    Just picked up a 1987 FJ60 with 174,000 miles over the weekend (not that I needed it :D) What should the compression be when performing a dry compression check? It came up at 160.
    thanks
     
  2. Degnol

    Degnol

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    That number sounds good, but more importantly, are all six within 10lbs? That's more important than the actual compression, down to a point, of course.
    GL
    Ed
     
  3. fsusteve

    fsusteve

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    10lbs or 10%? Thats what I've always used.
     
  4. Degnol

    Degnol

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    10% would give you a little more lattitude. I think you're right.
    So if your highest is 160 then the lowest could be 144 and every other cylider should fall between.
    Ed...I stand corrected...Long ;)
     
  5. petescoffee

    petescoffee

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    All were with in that range.
    Thanks for the input. :cheers:
     
  6. dogboy

    dogboy

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    minimum compression spec on the '60's 2F is 114 if memory serves me correctly, with a 10% discrepancy between cylinders O.K. -- sounds like you've got compression for days :)

    -dogboy- '87 FJ60
     
  7. tlcgear

    tlcgear

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    I know that the compression on my 73' 40 with an F engine in it should be arround 160.
     
  8. IDave

    IDave

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    The OEM Toyota F Engine Manual (page 2-6) states:

    "Specified compression: 10.5 kg/cm2 (150 psi) at 200 rpm.
    Limit - 9.0 kg/cm2 (128 psi)."

    Which is a 14.7% varience. :)

    I don't have a 2F manual, but according to Chilton's, they are the same for F and 2F.
     
  9. Mike S

    Mike S

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    Compression should be nominal 150. My FJ60 is 155 jigh, 140 low. Has 148K miles.

    Sounds like you are good to go.

    Mike S
     
  10. tlcgear

    tlcgear

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    I have a question along this lines... Is there any way to bring the compresion up w/o rebuilding the engine?

    - Rico.
     
  11. petescoffee

    petescoffee

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    To raise compression on my FJ40 2F during the rebuild I decked the block and Shaved the head as well as a new cam shaft RV grind.
    With our doing a complete rebuild you could do a valve job, have the head shave and replace the cam shaft with on with a RV grind.

    Thanks for the input on the compression test. :beer:
     
  12. Degnol

    Degnol

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    I stand ready to be corrected, but...If you check compression and get whatever reading then you squirt oil in that same cylinder and the number goes up, you have a ring/cylinder wall problem that will NOT be corrected with a valve job. If the number does not change, you MIGHT help compression with a renewed head, ie valve job., surfacing, head gasket. However, renewing the head with a weak lower end is asking for trouble, IMHO. Lower compression will affect your performance, but if all your #'s are within tolerable limits and you don't have any other glaring problems, do the whole thing at the same time. In other words, all things remaining equal, most parts wear out at the same pace, doing a valve job will only put more strain on other worn parts.
    Hope this makes sense. If you don't have a steady miss, don't obsess on the compression #'s.
    Ed Lonh :)
     
  13. hammerhead

    hammerhead

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    Go ahead and rebuild the head. Then when the bottom end shreds you have a good excuse to rebuild or replace. Hehehe...