page@ucla-cs.UUCP (12/12/84)
I just had my 78 Honda CVCC (77k mi.) tuned and the worksheet returned to me said that the compression was 170 in all four cylinders. My question is how to interpret this (I am obviously no mechanic). I do know that you want the compression in all cylinders to be within 5%. But how about the magnitude of the number? Am I right in bein pleased with this result? And should I be skeptical that all four cylinders are exactly the same?
hav@dual.UUCP (Helen Anne Vigneau) (12/19/84)
<*munch*> I'm not sure how to interpret the compression info either, but I do know that high means good and low means bad (in a nutshell). I also know from talking to three different Honda owners that the compression in Hondas gets higher as the car gets older (also the more you abuse it, it seems). We could never account for any of this, though. If you find out why, I'd be interested to find out. Helen Anne Vigneau Dual Systems Corporation
mikey@trsvax.UUCP (12/20/84)
As you break in an engine, the compression goes up from the rings seating and forming a better seal. Also, the more an engine gets carbon deposits, the compression will go up. There are two types of compression test. The dry test, which is where you just hook up the guage and measure, and the wet test, where you put a teaspoon of oil in each cylinder just before the test. If the compression is low on the dry test but is up on the wet test, then you have a ring problem. If it stays down, it is either a valve or something the oil is not reaching to. I heard a trick the other day on PBS Tv for getting rid of excess carbon in the cylinders without taking the head off. Get a windex bottle full of water and squirt it in the carb of a hot engine while at fast idle. Supposedly it will flake off the carbon. It usually will muck up the spark plugs, so they should be replaced/cleaned after doing this trick. mikey at trsvax 55, it's not just a good idea, it S*CKS!!