Bravo exhaust crack at #2 cylinder

[bbillb]

Today while changing the oil I noticed a crack in the exhaust in the weld at the #2cylinder.

The crack was in the weld at the transition of two tubes.  Just wondered if anyone else had run into 

this problem??  My aircraft has 881 hours and has NOT been run LOP.  Can anyone recommend an 

exhaust repair shop that they had a good experience with??  Thanks

 

Bob Byers

[Cris]

Quote: bbillb

Today while changing the oil I noticed a crack in the exhaust in the weld at the #2cylinder.

The crack was in the weld at the transition of two tubes.  Just wondered if anyone else had run into 

this problem??  My aircraft has 881 hours and has NOT been run LOP.  Can anyone recommend an 

exhaust repair shop that they had a good experience with??  Thanks

 

Bob Byers

[jetdriven]

Make sure they can weld 321 stainless. That whole idea sounds risky.  You can ask Aerospace Welding what they would do to repair it and the cost.

[aviatoreb]

Quote: bbillb

Today while changing the oil I noticed a crack in the exhaust in the weld at the #2cylinder.

The crack was in the weld at the transition of two tubes.  Just wondered if anyone else had run into 

this problem??  My aircraft has 881 hours and has NOT been run LOP.  Can anyone recommend an 

exhaust repair shop that they had a good experience with??  Thanks

 

Bob Byers

[johnggreen]

Bob,

I am pretty mechanically experienced, but I don't change the oil on the Bravo because of "exhaust issues".  What I mean by that is that a turbo and its exhuast system create a lot of heat and there are multiple points of potential failure.  When that cowling comes off for an oil change at 25 hours, I want lots of eyes inspecting the engine, turbo and exhuast system.  Now, if my shop were not so near and so reasonably priced, I might do it in my hangar with another mechanically talented friend to help.

Yours is a small problem to fix as long as the shop can weld stainless, but it is a serious problem that must be addressed before the airplane flies again.  I probably didn't need to say that.  I would think that any decent A&P can handle it for you whether he farms the welding out or is capable himself.  It is, after all, not rocket science.  But then a rubber O-ring brought down the space shuttle !!

Jgreen

[jetdriven]

Quote: aviatoreb

I have a different model airplane/engine - but I just had a similar crack dealt with.  The big central exhaust piece that brings all the other exaust tubes together had a large crack so it called for replacing the whole central piece.  I happens.  Why do you think LOP is part of the discussion?

[bbillb]

Didn't mean to start a controversy with my LOP statement but here is a statement from 

Don Kaye who has thousands of hours in the Bravo."

After the course I put on the GAMIs and successfully ran LOP for a few months until a mag was changed at Annual.  I never could get it to run LOP after that.  Others have reported having signifiant exhust repars after attempting the LOP experiment.  My advice, don't run LOP with this engine.

Anyway just wanted to let people know that running ROP you can still have exhaust problems.

After conversing with my mechanic decided to send the whole exhaust off to Aerospace Welding for 

inspection and repair as needed.

[thinwing]

My #2 was also cracked at prebuy....welded by knisely welding and no futher problems 350 hrs later.I also change my oil but for the reverse reason John Green suggusts...you have your mechanic change the oil...and they know they can probably charge out for 200 or 300 bucks...but they are human and get busy...they will give the engine a once over...BUT..the Bravo really needs a detailed inspection ( I requently take an hour alone on exaust and hose inspection...I do the air filter at that time...it is so easy to remove and than you have direct access to turbo charger impeller and can spin the turbine for signs of roughness.I also give all exaust slip joints a shot of mouse milk and lube the wastegate pivot point with same...probably does no good...but I have had very little problems with exaust system with no changes in condition...an oil change takes me 4 hrs...from runup to runup..k

[FoxMike]

Bob,

You may have noticed a crack at #2 but you need to take a close look at the cross over slip joint and the odd numbered cylinders. If the cross over slip joint seizes it can break welds on both sides of the engine. I used to be a fan of Lycoming but between the poorly designed exhaust and crankshafts I have put them in the same category with Continental. I use Heliarc in Denver for exhaust repairs.

Walt

[AndyFromCB]

Also, at each oild change, lube the slip joints and wastegate with mouse milk, my two cents...

[thinwing]

the mouse milk is probably doing the most good,...the way I have found to apply it is pour a little into an oil bottle cap(you get lots of these from the oil change)than use a long handled artist brush and "paint the joint"starting from the top so it wicks around joint.I have found far less mess than using oil can with hose...k