MooneyMark

Training has been slow the past six weeks, I did some practice runs to EHGG but this weekend I’ll be back at the flightschool. My dad passed away exactly one week ago, we operated the Mooney together and maintenance was completed just in time to do a very emotiononal farewel pass at his funeralservice. We both loved flying and we loved flying the Mooney together. He followed progress on maintenance right up to his passing and was thrilled to hear they finaly found a ‘smoking gun’ and the cause for the misterious oil consumption. I was in tears because at that time my dad was in the ICU fighting for his life and the doctors were still trying to figure out what was killing him. I said ‘dad, they fixed the Mooney, they will fix you too.’ Regretfully it wasn’t meant to be, he would have loved to take her up once more.

This is the little spring we found in the oilfilter. I suspect this debris could also be to blame for the failure of the automatic wastegate, it is a hydraulicaly operated system.

The e-mail my mechanic sent to Mooney and all other parties involved sorting my engine out. Maybe it can be of use for anyone else, so just putting it out there. Mind you, they checked the cilinders for oilleakage with an endoscope and had no reason to suspect the valvestem seals. ”Hi Guys, For a number of years we've been trying to solve the mystery of the oil coming from the exhaust tailpipe of a Mooney M20K with a TSIO360MB engine. (factory new 1989, 1168 TT, no major repairs been done to it apart from 1 cylinder change 2 years ago) Every time the aircraft was started up or flown the RH nose landing gear door and belly where wet of oil coming out of the tailpipe. At some point the turbocharger was changed. There was always about a cup of oil standing in the turbine housing. This didn't cure the problem. The one way valves in the oil system to/from the turbo where cleaned several times and eventually changed for new ones..... unfortunately no joy. We've checked the scavenge pump but it seemed OK. At some point the the starter clutch was broken and the complete housing was changed including the scavenge pump. We hoped that this would fix it..... No.... During a 100 hrs inspection some metal spring particles where found in the oil filter. Small bits like a lipseal spring. This gave me the idea to have a look at the intake valve guide seals since they have this kind of spring installed on the seals. I removed the valve springs and found 5 out of 6 seals being damaged. On 3 of them the springs where completely gone and on 2 others the seal was partially broken but the spring still in place. The only good seal was installed on a cylinder which I changed about 2 years ago. I guess that the one on the old cylinder was damaged too. I changed all 6 valve guide seals. Ran the engine and no more oil from the exhaust tail pipe. The aircraft has made several flights/starts since and so far good news. I thought this can be helpful to share. Greetings, Martijn”

Welcome WL, I'm not much help for you, had one mag failure but found out during run-up. I hope it all works out for you! For the other posters: how come the EGT goes up with one faulty mag? I'd imagine less mixture being burnt and thus a lower EGT...?

If it can break, it will at some point! I’ll keep you posted, thank you all for your input

He has added it to his list of possible causes. But he said they hardly break...

Thanks!

Well, that ship has sailed... It has already become very costly. I've asked my shop to check the O/B valve out. But is there an overboost valve on a automatic wastegate system? Guarding against overboost, Isn't this the work of the wastegate?

Thanks Jack, I'll check in to that!

Thanks again for you input, the wastegate moves freely and without any problems. It has been overhauled along with the controller by Main Turbo, the controller was sent back even, and replaced with another item. Great service from Main Turbo! My mechanic wil be on the telephone with Gary (Main) today, I hope he can shed some light on the matter. I've been doing some of my IR training now on a C172 now and that just isn't 'it'.

I guess with the overboost regulator you mean the wastegate? If not, please tell me more.

Can't say that I did. I did a trial run yesterday and now the wastegate remained open, so I had to reject the take-off. I was suspecting that may be with a colder engine/engine-oil I might get the same results as I did Saturday (36" take-off and then a reduction to 25/26" WOT), but the wastegate remains open all the time now.

When the waste gate is closed manually, the engine makes full power. The turbo itself is not at fault. There is something wrong between controller and wastegate, I guess...

Yes it does, you don't get any 'kick' from the turbocharger, that usualy makes it's presence know around the 27". But I do guess the fault lies somewhere hidden in a hose or linkage. All the components themselves check out fine.

Unfortunately I’m in need of your ideas again. My 1987 M20K 252 with just over 1000 hours total time is grounded for over five weeks now. It had some work done on the turbo due to the oil leaking from the exhaust. Nothing was replaced overhauled or repaired, save a few clamps. She flew fine for a few hours but she sits in the warm hangar of the maintenanceshop again. Take-off with full power and 36” MAP but just in to the climb the MAP drops to about 26” at WOT. What has been done? The turbo has been looked at and checked out okay, the output of the engine is okay, but the waste gate doesn’t seem to close. The controller and wastegate were shipped to Main Turbo for evaluation, the controller was out of spec and overhauled, the wastegate itself checked out okay but was overhauled anyway. Back on the engine, after some adjustments it seems to check out, but after a testflight yesterday we seem to be back at square one. I get full power at take-off but it drops off after rotation. Up in the air I tried different powersettings but did nog get more than 26”. That wastegate is not closing. I guess heat could have something to do with it? I tried another take-off after landing but had to reject it. I’ve read up on the subject with some of the great articles from Mike Busch (who doesn’t respond to e-mail BTW), six weeks ago I didn’t know what a controller was... do you guys have any thoughts?