the recent topic on rebuilds lead me to thinking. how many here have done or do regular checks on their engines. any of you do leakdown checks? I am hoping you know what I am talking about. the test checks the seal on your rings .by putting 100 psi in and seeing what they (rings) will hold you can determine leakage past the rings. what is good or bad? I see a 10 percent leak and I do the rings. that is my rule of thumb. the engine will still be running but not like it should. leakdown gauges, they are also availabe from harbour freight or by making your own ,snap on as well as others. however a recent test of the hf unit, showed it as having not so acurate gauges. it showed an extra 10 percent leak that was not present when we used a snap-on gauge. my homemade set uses Parker gauges and a good regulator. between the regulator/gauge and second gauge , you use a damper valve( in my case a piece of 1/8 inch pipe filled with epoxy and drilled using a .040 drill bit). from the second gauge to the plug hole adapter. after setting the regulator to 100 psi, you read the second gauge seeing what it will hold. easy to figure the leakage% that way. without the damper valve the second gauge will recover to fast and you will not see the leakage. I will post a pic of the rig soon.