Cylinder Rescue

Way too many cylinder wind up getting pulled due to low compression, says Mike Busch A&P/IA. Many of them can be rescued without resorting to cylinder removal. Mike illustrates this by telling the story of a frustrated Piper Seneca owner who had already replaced seven cylinders and was now being told by his mechanic that two more needed to be replaced. With the help of Mike's team, both cylinders were rescued without removal--one by lapping the valve in place and the other by doing a solvent ring flush. Mike feels that cylinder removal should be the last resort after these less-invasive methods have been tried. Savvy Aviation offers Professional Maintenance Services to owners of General Aviation aircraft, such as: SavvyMx (Professional Maintenance Management), SavvyQA (Expert Consulting), SavvyPrebuy, SavvyAnalysis (Engine Data Analysis) and Breakdown Assistance. Savvy also publishes a monthly newsletter with lots of interesting information for the general aviation enthusiast; subscribe to it at www.savvyaviat... or text the word "Savvy" to 33777. This webinar was hosted by the Experimental Aircraft Association (EAA).

[@colinmomberger1065]

I learned this technique from you eight years ago at Oshkosh. I have used it to rescue several cylinders for clients and have saved them thousands of dollars, as well as teach this to my A&P students and Repairmen at our Jetstream Aero Inc. A SAVVY Aviation G.A. AAA Repair Station in San Bernardino, Ca. Thanks again Mike!

[@Lehmerable]

Mike, I can not tell you how much your publications have helped me as a professional aircraft mechanic. Its frustrating to me that so many mechanics stress about lower than 70/80 compression numbers on Continentals and without using a borescope or understanding the master orifice, immediately jump to overhauling the cylinder. It ends up costing the customer a lot of money and wastes the mechanics time. One thing I would add, I found that you don't need to drop the exhaust to access the valve during a valve lapping procedure. If you use the tip of a zip tie, you can maneuver it with compound through the top spark plug hole.

[@edwardallan197]

I love the minute details interwoven with guiding ideas. I am learning a LOT. Thank you!

[@dougm2745]

Learn so much from watching these. Thanks!

[@usmcmech96]

Back when the original FARs were written, compression was the best diagnostic tool they had. Today we have a much better idea of what's going on inside of the engine.

[@marknielsen8738]

What do you think was it Orville or Wilber that wrote that section of FAR's??

[@crawford323]

@@marknielsen8738It was Charlie Taylor.

[@apfelsnutz]

Thanks Mike, I'm replacing the rotor coils on my Navion E-225 this annual...

[@MayhemCanuck]

As an Automotive tech doing compression test is nothing new. But its interesting, as what you call a compression test we call a cylinder leak-down test, witch we do after the compression test if we have a noticeably low cylinder compared to the others. Cylinder low compared to others, Leak-down test at TDC and see where the air leakage is then a bore scope check, witch we have been doing for a long time since camera prices came down. I think I'm buying a VA-400, it will be a great tool to look up into the cylinder as the one I have only looks down or 90 degrees. Its nice to show the client/customer actually whats wrong.

[@jimrankin2583]

rope trick is best done with nylon braided rope that won’t leave debris in the cylinder. It’s softer and confirms to the space better than poly or sisal fiber rope.

[@savvyaviation]

good tip!

[@jimrankin2583]

The old hand spindles with the suction cup on the end that were used to use to lap valves when the head is off an engine required you to reverse the direction of rotation. I doubt it’s important to do that but it was how the procedure used to be accomplished.

[@apfelsnutz]

Looking forward to this one...

[@apfelsnutz]

Make sure you wait a while before you do the second flush. I did this on a Darter 100 that had set for 16yrs. in a very hot "hangar" in the middle of the desert... no problems.

[@marknielsen8738]

No problem for the engine, you on the other hand... LOL

[@apfelsnutz]

@@marknielsen8738 Yeah, I've always been inquisitive... and most of the time boring... Lol !

[@apfelsnutz]

MMO and Lacquer Thinner works like perfect

[@briand3837]

I remember staking the exhaust valve as a means to get rid of any carbon buildup that might be keeping the valve from fully closing.

[@FlyingNDriving]

So if you have a high use of mogas, a cylinder flush shouldnt be that sludged up since most of the sludge is from lead from 100LL?

[@BonanzaPilot]

what would it take to get Mike a good mic?

[@danielwu346]

and a good internet connection; so many dropped audio packets in this recording

[@derekevans7829]

Hey Mike, I am Savvy Pro user, and I have a question in regards to the cylinder wash. I live in California, and I cannot acquire Xylene and "real" mineral spirits. Will the substitute products at my local Home Depot/Lowes be sufficient? Thanks!

[@SMcda]

get out while you can

[@l19birdog]

I have a 10 over cylinder with 200 hrs on since rebuild. It has a loose valve guide. The local shop could not repair it and recommended a another shop that might could install a 30 over guide. Is it acceptable to install a new standard bore cylinder mixed with the 10 over cylinders?

[@marklandry2509]

Is it feasible regarding the worn cylinder to pull it, replace the rings and re-hone it similar to what is commonly done to outboard motors that lose compression.

[@rickseeman5679]

I love this guy

[@johncarr123]

Do you have talks about Lycoming compressions?

[@MeaHeaR]

I cant hear the Audio keep chopping up und Going soft und Loud unt All be Terribly Distorted

[@FlyingNDriving]

1:15:48 How about some Franklin love!?

[@ricktrentoi3]

Can owners do this lapping method or is an A&P required?

[@watashiandroid8314]

This was answered in the Q&A section. He basically said it's a big stretch to consider it preventative maintenance. From my unqualified understanding, assuming FAA rules apply, a normal certified aircraft would need an A&P and anyone could legally perform it on an experimental amateur built aircraft.

[@bernardc2553]

The only "positive" when staking a valve IF it has alot of carbon build-up under, is shocking W/O dislodging keepers..is occasionally it dislodges some chunks of carbon off ..

[@musketeerflyer]

This video has an encyclopedia's volume of information, but is painful to watch with the slow speech and pauses!

[@bernardc2553]

1st thumb now waiting for thumb 2

[@88MasterBuck]

So if I call Contintental right now, they will approve of dumping solvent into their motors? Secondly, I agree that lapping of the valves is a commonly performed procedure done during cylinder work at engine shops, but with the jug off of the motor, since lapping the valve can inadvertently re-contour the shape of the valve, thus the angle of the valve (after lapping) can be measured to ensure it's still within spec, and not exceeded which of course can cause hot spots, pre-ignition and detonation. These are measurements which, after lapping, can not be ensured or properly measured with the jug still on the motor. In not saying is can't be done, or shouldn't ever be done. I'm just saying that's a major factor in why we prefer to have valve work done while the jug is off the aircraft, and in the hands of someone who does it all day, every day. The cylinder's static compression is quite far down my list before the safety of the pilot. Thirdly, I would highly advise you not "give a little ammunition" (i.e. push) a rated mechanic to perform a procedure which he has never done, or is uncomfortable doing, which is actually against the regs. Lastly, I doubt if I called my local PMI, he would concur that a pilot dumping solvent in his cylinders falls under the category of owner-operator preventative maintenance. PLEASE call your FSDO and ask before ever doing these types of things. I will go ahead and make these calls today (continental and my local FSDO) and if im wrong, I'm excited as a rated mechanic to have learned something new from you. If you're wrong, the advise in this video is beyond troubling. Mr. Busch, I advocated for you to my mentors throughout the entire process of my apprenticeship in the efforts to obtain my ratings, citing the belief that their experience in what works and doesn't, does not damn your credentials in the effort only to follow the regulations. But as time has gone on, I am troubled to state that I have never come across a rated mechanic in this industry who has anything good to say about you, specifically because you give shoty advise, and encourage pilots, owners and operators to do things they have NO BUISENESS doing on their aircraft, your advise frequently if not always leads to them disregarding their mechanics' professional recommendations, furthermore eroding the trusting relationships between said parties. I guess we shall see where this goes.

[@savvyaviation]

I'm sure you correct about what Continental product support and your PMI would say. Both of them would very likely discourage performing any procedure not explicitly approved in writing by the manufacturer. Fortunately, the regulations do not limit mechanics to performing only those tasks prescribed by the manufacturer or approved by the FAA. It they did, we could never innovate in our maintenance procedures. Innovation -- finding better ways to do things -- is a big part of Savvy's DNA. A lot of A&Ps resist innovation, and were taught that they must always do everything "by the book." So there is sometimes some creative tension between Savvy and the A&Ps in the field that we work with. That's a good thing. We do our best to persuade A&Ps to use innovative practices, but if they're doing the work they always have the last word because it's their signature in the logbook. If the owner doesn't like it, it's always his option to take his aircraft to a different A&P whose butt muscles aren't so tightly clenched. The relevant regulation [43.13(a)] permits us to-either- use the methods, techniques and practices prescribed by the manufacturer in the AMM or ICA, -or- "other methods, techniques, and practices acceptable to the Administrator." That last phrase is what gives us all sorts of wiggle room in terms of methods, techniques and practices. There's quite a bit of written guidance from the FAA about exactly what that last part means. "Acceptable to the Administrator" does NOT mean "approved by the Administrator." The FAA makes it quite clear that the FAA does not have to have ever looked at something for it to be "acceptable." All that is required is that the mechanic using the method, technique or practice have a good-faith belief that the FAA would not find it unacceptable if it ever looked at it. Since it's highly unlikely that the FAA would find valve lapping or solvent ring flushing unacceptable (since it doesn't violate any regulations), we see no problem in recommending it regardless of what Continental or some local PMI might say. Savvy has been pretty public about our recommendations about valve lapping and solvent ring flushing, and so far we haven't heard a peep from anyone in the FAA about it. That gives me a lot of confidence that it's "acceptable to the Administrator." (If and when someone from AFS-300 notifies us that the FAA finds it unacceptable, we would certainly change our tune, but I don't expect that to happen.) Certainly an aircraft owner who performs preventive maintenance is not expected to consult the FSDO before he does so. Furthermore, the FAA's Coleal Interpretation makes it clear that owner-performed preventive maintenance is NOT limited to the 31 tasks explicitly listed in Part 43 Appendix A(c), and that there are many other tasks that the FAA would consider to be preventive maintenance beyond those 31 listed items. We've never stated that a solvent ring flush is preventive maintenance, we've only said that it is so simple that it probably could be considered to be preventive maintenance. It would be up to the owner who was thinking about performing this procedure himself to determine for himself whether it is preventive maintenance or not under the FAR 1.1 definition of that term. Many A&Ps that Savvy works with have a similar reaction to these things as the one you have expressed. We're used to it and we can be pretty persuasive when we need to be. But we never ask any A&P to perform any task he's uncomfortable performing. The A&P performing the work always has the last word. --Mike

[@tanitsornchan6735]

😅😅😅😅😅😅😅😅😅

[@conantdog]

I really respect you and your knowledge but I wouldn't be advising customers with cars to take their plugs out and to try lapping their valves for flushing a cylinder that should be replaced. Four wheels on the ground you can do all this stuff get away with it in the air sounds kind of sketchy to me.