Post by roger on Aug 9, 2016 9:34:29 GMT -9
As I posted elsewhere, we just put 2 factory overhauled motors on our Chieftain. Now 200 hours in and we've had an exhaust riser pipe crack at the flange to the transition and changed half the intake gaskets due to intake leaks.
When we started pulling apart the exhaust to change the broken piece, we found all the slip joints on those aft 3 pipes were seized solid-probably why it cracked. I know my guys put liberal anti-seize on the slip joints when we had them apart to put the engine mount on, and we douse the joints in mouse milk every time we have the cowlings off. Worked good on our last set of engines, other than a couple bits that Lyc changed when they went back for prop strike inspection at midtime the slip joints stayed nice and free for 2060 hours and no cracking. I don't know if Lyc has changed the fit tolerances on those pipes or what.
On the intakes, it looks like what has been happening is they painted the flange of the intake pipes, and as the paint comes off the gasket and joint lose their clamping force leading to a leak. A couple have had the inboard bolt barely tight when we go to change the gasket, not sure if they weren't put on tight enough or if it's just the loss of tightness from paint coming off the joint. Will be filing SDR's on the intakes, probably not the exhaust just due to that being a known issue.
When we started pulling apart the exhaust to change the broken piece, we found all the slip joints on those aft 3 pipes were seized solid-probably why it cracked. I know my guys put liberal anti-seize on the slip joints when we had them apart to put the engine mount on, and we douse the joints in mouse milk every time we have the cowlings off. Worked good on our last set of engines, other than a couple bits that Lyc changed when they went back for prop strike inspection at midtime the slip joints stayed nice and free for 2060 hours and no cracking. I don't know if Lyc has changed the fit tolerances on those pipes or what.
On the intakes, it looks like what has been happening is they painted the flange of the intake pipes, and as the paint comes off the gasket and joint lose their clamping force leading to a leak. A couple have had the inboard bolt barely tight when we go to change the gasket, not sure if they weren't put on tight enough or if it's just the loss of tightness from paint coming off the joint. Will be filing SDR's on the intakes, probably not the exhaust just due to that being a known issue.
