so i am guessing that a range of 131 to 135 is good compression...chitown40 said:Per FSM, 149/cylinder is what it should have started with back in '87. So, like Al said, as long as there is less than a 10% difference between cylinders you should be ok.
NocalFJ60 said:If it is low then you can add some oil to the cylinder and retest. If the pressure comes up then that means the oil helped seal up the rings to increase the pressure. The dry measurement is just after the engine is warm without adding oil. The typical service dept. would just do a dry probably unless one was low and then you can use the wet to tell if it the rings.
Thanks for the added detail.chitown40 said:If your compression is good dry, then you don't need to do a wet test. You can do a wet test to try to determine if the rings are bad or if the problem is in the head. Also a leakdown test using shop air can give you lots of info. I never did a leakdown test, as I was able to determine most of my engine problems with a dry and wet test. NO change in my one bad cylinder and it turned out to be a bad valve from a cracked intake manifold. This is common on the 2F's because the heat risers sometimes stick in the closed position thereby overheating the aluminum intakes and causing them to crack right under the carb.