astrowrench
Member
Sorry I hit the #1 My Bad ........Dave
compression
- Thread starter trucker3495
- Start date
Neither one is better or worse, they are just different. Leakdown can give more information on where the loss is, compression can tell you the actual pumping efficiency, but having an air density gauge is important for that.
Comparing leakdown numbers without knowing the orifice size used can be very misleading. Since these motors have small bores, I tend to test at lower pressures too. I know the standard for FAA is 100PSI but personally I think thats way to much to get an accurate reading on a small motor, only so much can leak at a given pressure. When you exceed that pressure and you are at a point of diminishing returns as the pressure goes up and the actual % leak shown on the gauges gets smaller.
Even without an actual leakdown gauge, if apply pressure to the cylinder and you hear anything getting past the valves, IMO you should work them. There will always be some leakage past the rings but the valves you should be able to stop leakage past.
Comparing leakdown numbers without knowing the orifice size used can be very misleading. Since these motors have small bores, I tend to test at lower pressures too. I know the standard for FAA is 100PSI but personally I think thats way to much to get an accurate reading on a small motor, only so much can leak at a given pressure. When you exceed that pressure and you are at a point of diminishing returns as the pressure goes up and the actual % leak shown on the gauges gets smaller.
Even without an actual leakdown gauge, if apply pressure to the cylinder and you hear anything getting past the valves, IMO you should work them. There will always be some leakage past the rings but the valves you should be able to stop leakage past.
sCREamnClones
New member
Each gauge and set-up ie unique in its application. You can/will establish your own routine and 'numbers'. "I" consider <6% 'very good' and anything >12-15%...'concerning'! A lot of 'things' enter into 'Leak' readings.
astrowrench
Member
Well said I test @ 60psi
alvin l nunley
Site Supporter
just to let you know, green is very hard, if not impossible, to read.
youngengines
Member
Just take the starter off and use a electric starter, check compression with a gauge. My RWYB shows 225+lbs like that.