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ZUKIWORLD Discussion Forum => Technical Discussion - Performance / Modify => Topic started by: JAMES44 on May 27, 2017, 03:34:45 AM

Title: COMPRESSION TEST CYLINDERS SAMARI 1987 jEEP
Post by: JAMES44 on May 27, 2017, 03:34:45 AM
    Hi,
           Just done a cylinder compression test   readings were
     NO1 CYLINDER=180 PSI
     NO2 CYLINDER= 185 PSI
      NO3 CYLINDER= 182 PSI
       NO4 CYLINDER -178 PSI
           Which seems okay ...engine has done 99,800 miles to date.....
         Seems down on power.....though..will check timing later.today....
                       Jim.
Title: Re: COMPRESSION TEST CYLINDERS SAMARI 1987 jEEP
Post by: TioPick on May 27, 2017, 11:06:53 AM
Did you check "dry" and after squirting some oil in?  Seem to be good numbers and in a reasonable +- range of each other.  Does it give a puff of smoke when started after sitting awhile?   Sometimes that means some oil is seeping past the guides while sitting.  just mi dos pesos
Title: Re: COMPRESSION TEST CYLINDERS SAMARI 1987 jEEP
Post by: JAMES44 on May 27, 2017, 11:14:59 PM
   I ran the engine for 10 minutes before doing the test ...there is no smoke at start up at all....it uses very little oil..
         Jim...
Title: Re: COMPRESSION TEST CYLINDERS SAMARI 1987 jEEP
Post by: fordem on May 28, 2017, 05:47:27 AM
At a glance those numbers are good, but the point that TioPick is making, and it's a very valid point, is that we don't know how the compression test was done.  I'm not singling you out here, but many people do not know the right way to do a compression test, and one of the questions he asked, or alluded to, was whether those numbers were wet or dry - and that question has not been answered.

The validity of a compression test is not really what the number say, but how the numbers change, between the wet & dry tests, and also from cylinder to cylinder.

So - on the surface of it, those numbers are within spec., but, with no more information than what has been provided, there is very little we can tell you.

For what it's worth, I had a Suzuki G13 engine with a little over 120k miles on it, essentially the same engine that you're looking at, but not from a Samurai, with compression numbers into the 190's, so apparently well within spec., but the engine was woefully down on power, because the rings were worn - maybe I should mention that those 190's were wet test numbers, the dry test numbers were in the 100~120 psi range.
Title: Re: COMPRESSION TEST CYLINDERS SAMARI 1987 jEEP
Post by: JAMES44 on June 25, 2017, 07:54:49 AM
Done after running engine for 10 minutes
    jim