CPSONE
Well Known Member
Not on an RV but worth sharing as it happened on TO-360's yes both!
Came back from a flight a while ago in my Turbo Seminole and found oil coating the bottom of one wing behind the left engine. Lost about 1/2 a quart in an hour flight. Upon inspection a very small amount of oil was found to have been seeping out the top of the dipstick (through the shaft retaining pin in the screw cap and out the top around the shaft itself, this was a big clue). Dipstick was installed and tightened correctly. The magnetos (dual mags in 1 housing) had oil on the bottom of the housing and been having problems with the mag seal so thought the seal went again. Sent the mag in for overhaul and turns out the previous engine shop put it together wrong and it was indeed leaking.
I had the magneto on my other engine also removed / overhauled / put back together correctly and it turns out it had just started to leak oil too.
Got it all back together, ran ok, mag drops ok so took it for a short flight.
Checked the bottom of the wings behind the engines, right one clean, left one covered with oil again! Bottom of the mag housing was dry. Oil must be blowing out the breather. Compression check was carried out and #2. I think it was had 0 compression. Cylinder came off and both compression rings were broken. It was a lycoming cylinder that had an eci cerminyl overhaul which takes a special piston ring. Turns out the engine shop that put it together used the wrong rings. I had all the other cylinders pulled $$$ and we found one more broken ring. Had all the rings replaced with the proper ones and it runs and flies better than ever. My wallet, lighter than ever...
Came back from a flight a while ago in my Turbo Seminole and found oil coating the bottom of one wing behind the left engine. Lost about 1/2 a quart in an hour flight. Upon inspection a very small amount of oil was found to have been seeping out the top of the dipstick (through the shaft retaining pin in the screw cap and out the top around the shaft itself, this was a big clue). Dipstick was installed and tightened correctly. The magnetos (dual mags in 1 housing) had oil on the bottom of the housing and been having problems with the mag seal so thought the seal went again. Sent the mag in for overhaul and turns out the previous engine shop put it together wrong and it was indeed leaking.
I had the magneto on my other engine also removed / overhauled / put back together correctly and it turns out it had just started to leak oil too.
Got it all back together, ran ok, mag drops ok so took it for a short flight.
Checked the bottom of the wings behind the engines, right one clean, left one covered with oil again! Bottom of the mag housing was dry. Oil must be blowing out the breather. Compression check was carried out and #2. I think it was had 0 compression. Cylinder came off and both compression rings were broken. It was a lycoming cylinder that had an eci cerminyl overhaul which takes a special piston ring. Turns out the engine shop that put it together used the wrong rings. I had all the other cylinders pulled $$$ and we found one more broken ring. Had all the rings replaced with the proper ones and it runs and flies better than ever. My wallet, lighter than ever...