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Compression specs for all 1st and 2nd gen tacomas

Discussion in 'Technical Chat' started by 95 taco, Mar 19, 2014.

  1. Mar 19, 2014 at 3:39 PM
    #1
    95 taco

    95 taco [OP] Battle Born

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    OME 883 front, OMD 3.5" rear, Relentless front bumper, smittybilt 9.5K winch
    1st gen (95.5-04)
    2.4L L4 (2RZ-FE) and 2.7L L4 (3RZ-FE)


    Run engine until it's at operating temperature, remove coils and spark plugs, fully open throttle, and install your compression tester in the number 1 cylinder, engage starter for 4-5 engine revolutions, and read results. (Repeat or each cylinder)
    Compression should be around 178 PSI , Minimum pressure is 127 PSI.

    The difference between cylinders should be 14 PSI or less.

    For the 3.4L V6 (5VZ-FE)

    Run engine until it's at operating temperature, remove coils and spark plugs, fully open throttle, and install your compression tester in the number 1 cylinder, engage starter for 4-5 engine revolutions, and read results. (Repeat or each cylinder)

    compression should be around 174 PSI , Minimum pressure is 145 PSI.

    The difference between cylinders should be 15 PSI or less.

    For 2nd gens (05-current)

    2.7L L4 (2TR-FE)

    Run engine until it's at operating temperature, remove coils and spark plugs, disconnect fuel injector connection, and install your compression tester in the number 1 cylinder, engage starter for 4-5 engine revolutions, and read results. (Repeat or each cylinder)

    Compression should be around 178 PSI , Minimum pressure is 128 PSI.

    The difference between cylinders should be 10 PSI or less.

    For the 4.0 V6 (1GR-FE)

    Run engine until it's at operating temperature, remove coils and spark plugs, fully open throttle, and install your compression tester in the number 1 cylinder, engage starter for 4-5 engine revolutions, and read results. (Repeat or each cylinder)

    Compression should be around 189 PSI, minimum pressure is 145 PSI.

    The difference between each cylinder should be 15 PSI or less.


    I'm not sure how accurate this data is, but i pulled it off of the all data system at school.
     
    SR-71A likes this.
  2. Mar 19, 2014 at 3:42 PM
    #2
    4WD

    4WD cRaZy oLdmAn

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    189 psi seems a little high for the 4.0 but i dont know
     
  3. Dec 29, 2022 at 10:46 AM
    #3
    blackZEBRA

    blackZEBRA Well-Known Member

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    Do you remove the all the coils/ plugs when testing or only for the cylinder you're testing and re-install them when you move onto the next one?
     
  4. Dec 29, 2022 at 10:51 AM
    #4
    Bishop84

    Bishop84 Well-Known Member

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    Altitude matters as well. We rarely see above 160. I’m 1km above sea level.

    big thing is above 125psi and all within 10psi ideally.
     
    GilbertOz, vern650 and SR-71A like this.
  5. Dec 31, 2022 at 1:31 PM
    #5
    vern650

    vern650 Well-Known Member

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    Yup, you can’t just have a set number and say it’s supposed to be xxx when it comes to compression. Every elevation is going to be different. I live at 4500ft above sea level. I’ll never see the same as some one at sea level. The variation from cylinder to cylinder is far more important than any specific target number.
     
  6. Feb 4, 2023 at 10:25 PM
    #6
    GilbertOz

    GilbertOz Driver

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    I'll share my preliminary & non-factory-spec compression test results here:

    4.0L V6 1GR-FE, 2014 Taco with 68K miles, operating normally. No oil or coolant consumption. Normal power output, cranking & revving sounds, mileage, exhaust characteristics, etc.

    Test conditions: ~58ºF ambient temp, altitude ~1350 ft ASL, engine COLD (had not been started / run for >24 hours.) Throttle CLOSED.
    Opposite bank (other side of engine) had plugs IN & torqued during testing. (Bank under test had all 3 plugs out.)

    Tools:
    Mityvac® MV5530 compression tester, using a single adaptor hose. (No multiple hoses/extensions.)

    No key in ignition. Cranked using a remote starter cranking switch, 7 to 9 seconds or so, until compression gauge needle stopped increasing. Charged battery for ~10 mins between compression runs using a NOCO trickle charger.

    Results, in PSI
    Passenger side
    Cylinder 1: 196
    Cylinder 3: 199
    Cylinder 5: 190

    Driver side
    Cylinder 2: 198
    Cylinder 4: 197
    Cylinder 6: 199

    Happy with these provisional results. Next time I will do the test according to service spec on a warm engine, being sure to prop the throttle fully open & removing all spark plugs on both sides. Will edit/update this post with additional results then.

    I also took extensive, good-quality flex-neck camera (not going to call it a borescope) video of the interiors of all the cylinders, including cylinder side walls, valve bottoms, & head gasket interface. Everything looks more or less normal, considerable (but not excessive) carbon build up. Some strong vertical scoring in certain cylinders, but all cylinders still show cross-hatch honing marks. No sign of slap or side-wearing. After I get all the video up (30+ minutes) on youtube I will make a separate post for that & then cross-link the post here for those interested. One person's data point for a "4.0 V6 1GR-FE in decent operating condition" baseline.

    I tried to do a leakdown test as well, but found that my small air compressor can only put out around 95 PSI. Not enough to get decent leakdown results.
     
    Last edited: Feb 4, 2023

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