Lapping a Valve in Place
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- čas přidán 11. 04. 2022
- Do you have a cylinder with low compressions and leakage past the exhaust valve? Don't yank that cylinder! Savvy's CEO Mike Busch explains the process of lapping an exhaust valve in place, a procedure that any A&P (or owner, under supervision) can perform without exotic tools. Watch as Mike cleans up the valves on his own engine with detailed video and commentary.
- Auta a dopravní prostředky
Thank you, Mike. My IO-520 developed an exhaust leak and the compression dropped from 77/80 to 63/80 (hot) on cyl #2. Tried staking the valve...no bueno. Then, I found your video. I purchased all the exact same materials/tools that you used, except for the borescope; I went with a Teslong articulating unit ($129 on Amazon). After lapping, the compression is now 74/80 (COLD!) and there is NO exhaust leak! Now, I've gone down the "rabbit hole" of Savvy videos and will probably surface some time next year, lol.
I had rapidly decreasing compression in the #4 cylinder of the right IO320 in my PA30. One mechanic told me to call a specific supplier and ask for a new cylinder. Another mechanic came over 15 mins later with a borescope and noticed nothing wrong, except fauled exhaust valve and seat. Compression was 78/80 50 hours prior, 70/80 20 flight hours prior, now 65/80 hot and 40/80 cold with air escaping through the exhaust. My mechanic promised to show her new mechanics and me how to lap a valve. However, after watching this video, I did the job myself after she provided me with the materials and showed her the result. 2 hours later, compression was back to 78/80 cold! Thank you Mike Bush for this great video!
I've often said, "if you wanna know how to do something, find an old guy with suspenders on, buy him lunch and ask him how" each passing day I get closer to being the guy with suspenders on. This video reminds me I still have plenty of lunches to buy. Thanks for making the effort to video your work, that is a whole job unto itself for our benefit and I appreciate it, whoever I am....
Excellent video! I have been doing this for 40+ years with great success. Current engine is at 2900+ hours, 3 original cylinders, never a burned valve.
A few comments.
First, don't wait for the asymmetric borescope pattern, by then there is already significant damage. My mentor's mantra, way pre-borescope, was "if it's leaking, it's burning". If you hear air at the exhaust pipe during a compression test, fly 10 or 15 hours and recheck. If it's still leaking, lap it. Will you occasionally lap a valve that would have survived anyway? Probably, but really cheap insurance.
Second, when rotating with the drill it's good to lift the valve on and off the seat frequently, and reverse directions occasionally. That way you get a more random lapping pattern and don't grind "tracks" into the sealing surfaces.
Third, for clean-up what works really well is to dampen a strip of soft cloth with solvent or avgas, and working through the top spark plug hole drape it over the open valve with a piece of soft (e.g. copper) wire. Pull the valve shut against the cloth strip and rotate the valve to wipe the entire sealing surface. With the right amount of pressure, you can get the cloth to wrap around the valve so as you pull it out it will wipe the entire seat. Do this 2 or 3 times and things are very clean.
For anyone interested there is a detailed step-by-step description of the procedure I was taught, which is very close to what Mike does, in the August 2021 ABS Magazine (p. 43).
Great advice thanks! I suppose one could put another saturated cloth inside the cylinder in case any compound fell off the valve.
One of the most enlightening and enjoyable videos ever for me. Im amazed!
I've done this for years (since the 1970's) with great success. I'm glad to see he used a drill. So many people are of the opinion this needs to be done by hand. Not so. Using power tools makes the job possible and practical. I typically remove the exhaust pipe to apply and clean the valve grinding compound.
I have never heard that, very smart.
10:34 I wouldn't categorize this procedure as "non-invasive", but rather: minimally invasive, because the cylinder was opened and invaded by a borescope, cotton tipped applicators, and grinding compound.
Sorry to be so nit-picky. I love these videos. Mr. Busch is a blessing to airplane owners, pilots, mechanics, and readers of his phenomenal AOPA Pilot columns.
Mike thanks so much for all you do for us GA guys! I am thankful for you and your team at Savvy! My 310 is in annual now and will have this done as well, thanks to you.
Bob, my Savvy MX account manager, has made my first year of airplane ownership a lot less stressful than it would have otherwise been. Keep up the great work.
A long passed AME taught this trick to me 23yrs ago. I am glad to see a video preserving the knowledge.
Excellent information Thank You Mike Busch
Had Joe Pasquale do this to three of our cylinders. Worked very well -- bulls eye pattern was restored as we put time on them. Joe was one of the first I know of to theorize that a failed rotator is ofter the cause of problems. Probably a good idea to replace the rotator while you're in there....Good high quality video - thanks for sharing this!
Thanks Mike. The best video yet showing this procedure.
Unbelievable! Mike, please keep the content coming! Thank you, sir.
As a tangent to this, I would be very interested in seeing a video of the procedure you have mentioned involving using solvent to rinse out the combustion chamber to unstick an oil ring
Seconded.
My owner of his over TBO B58 undsr my supervisinf did the ring flush and it reduced the oil consumption I think it will be a regular item to accomplish monitoring oil comsumption
I agree big time. I’d love to see that other procedure being done on a video
I'd 4th or 5th free & clean thee rings 1 too
That was amazing and very interesting to see you perform the procedure. Like watching one of the heart valves function.
Thankyou sir.
🌏🇦🇺
Amazing procedure!
Excellent video. Thankyou for posting. 👌
Thanks for a great video. I am about to do 2 cylinders on an IO-470 that is in for annual. The owner of the plane was skeptical. Your video which perfectly demonstrates the process gave the owner the perspective to approve lapping the valves without removing the cylinders. Prior to that he was skeptical. If I may make a suggestion, it would be helpful if you added links to the products like the gun cleaners and grinding compound in the video description. Maybe you could start an Amazon Store of recommended products?
It would be difficult to remove all of the grinding compound. Aren't you worried that some of it may get onto the cylinder walls and erode the piston rings?
Amazing video! I performed this procedure yesterday which worked perfectly in eliminating a minor exhaust valve leak. Toughest part was cleaning up the compound around the valve when finished although that wasn’t terribly bad. Just take your time and use plenty of swabs. Thank you for posting!
You do an excellent job with smart solutions everytime. I'm a big fan of you Mike.. Thanks for sharing these valuable contents with us.
Excellent, los admiro mucho, por su profesionalismo 👍🏻🙌🏻
Great job guys just brilliant 😊
Thanks, Mike. Great video. What is the source for the valve spring compressor tool used?
I love the way Busch claims these procedures as his own that he developed. they have been around for years.
Can you point out for us the exact time stamp in the video where he claimed he invented this procedure? Because I watched the whole thing and I didn't hear him say one singe word whcih could be remotely construed as him claiming this was his own invention ... so maybe I missed it.
Absolutely beautiful
I def want to see how it looks after 5-10 hours of flying it after this!
Good job.
Thanks a lot Mike for your sharing. I wondered that It would be difficult to remove all of the grinding compound. How do you do this ? Could we use a vacuum cleaner on the exhaust pipe and send some sort of solvent into the cylinder?
Thanks for the time and effort to create this video. I learned a lot. I understand the reason for lapping the exhaust valve, but I noticed that you had plastic tubing over the end of the intake valve as well and you had a drill bit in the other end of the plastic tubing as though it were ready to be lapped. I’m curious as to whether or not you intend to lap the intake valve, perhaps to ensure that there is no small piece of debris on the seat?
My guess is it was just being used as a convenient holder to minimize how far his arms needed to travel. Just a guess mind you
I’ve done this taking off the exhaust before I wish I had seen this before the last time my Savy Aviator Customer and I did this on all cyls & Replaces All Rotors… engs are over TBO & Counting…
I am trying this on my Tiger's lycoming that # 3 exhaust valve fluncked comp chk.(I am AP)
Valve guide passed wobble chk but valve leaks around the seat.
Using power drill as suggested, but wondering how long it typically takes to make headway--been grinding about 20 min so far, not alot of progress. Video doesn't mention how long total time spent lapping...
Great clear video, and just in time-I need to do this to all 6 of my valves this June. I saw Mike discuss this on SocialFlight and the topic of abrasive removal came up- I thought I remembered him saying any residual would probably all just blow out the first time the cylinder was fired up. Is this correct? Another well done video recommended using a water soluble abrasive for easier cleanup?
I’m not looking forward to it, but it certainly beats pulling cylinders with all the downsides of that!
I would suggest just blowing it out by running it IF your engine is naturally aspirated.
Would not suggest it if your engine has a turbo. All that hailing of micro-FOD wont be good for the turbine.
Mike, I noticed that you had the intake valve setup for the same procedure in the video. Did you lap the intake also??????
Great info. I have the Vividia 400 borescope and the images are nowhere near as detailed as yours. I’m jealous
SOoo Mike with what little is taken off , have you ever had to change Pushrod to correct installed height?
Wow...does the borescope have a built in mike? Sounds like it does.
3:00 The audio volume of this presentation is somewhat low so I could not understand what was being explained about the purpose if inserting rope into the cylinder.
What type of valve spring compressor tool are you using?
Is there any difference in the procedure for a Lycoming with the sodium filled valves?
Does anyone know where to buy that valve spring compressor tool?
8:48 It would have been excellent to view the valve seat close up before lapping, to better understand the why this procedure is so valuable. And I admit being somewhat disappointed at not being shown the valve seat close up after the grinding compound was removed at 11:00.
Pretty genius
Can I download the video? If so, how? Thanks.
It it my imagination or do I see side slop in the valve guide? Looks like a bit of oil in the combustion chamber. The side to side may prevent the rotator from working.
How do you get cylinder video that clear with the VA-400 borescope? I have that exact modem and have never seen images anywhere close to that clear.
Yeah, I have a Vividia borescope with a flex shaft, whcih I assume has the same camera and other electronics, and my images are nowhere near that clear. I'd like to hear how he does it, as I seem to be missing something.
Buenisimo
Why do images from my Vavidia 400 not look anywhere near that clear?
Is that procedure in the manual? I spent the bulk of my A&P career on turboprops rather than recip engines but I've done a lot of Recep engines in non aviation applications. I wouldn't do that to a Chevy let alone an aircraft. If a valve needs more than staking it needs a valve job. Valve lapping is to be a quick final polishing of the valve job not in lue of a valve job. Don't get me wrong if I was stuck on a desert island and that airplane was the only way home I'd do it in a second.
2:32Great trick for testing the rotator. Looking at the wear mark on the valve stem tip, was the valve rotating with the rotator?
I rewatched it a few times and I think you are right
It's often surprising that it takes so little actual grinding time.
This is a great tip, however, in some cases you might want to do this a bit less intense than what you have shown. Removing carbon and lead should be pretty easy. I was always taught to lap as little as possible. Over-lapping causes problems by making the sealing surface too large or grooved thus decreasing the PSI on the sealing surfaces. This then makes the seat even more susceptible to carbon build up and subsequent burning due to a reduced ability to transfer heat from the valve to the seat. Just enough is best, if you can manage it.
Mike or anyone else with experience lapping valves in cylinders, how important is it the get every speck of compound out of the combustion cylinder and valve surfaces? We just performed this on a valve that was sealing ok but had 2 area of heat issues. We suspected Roto-Coil rotation problem. We used solvent soaked applicators and wiped the valve while turning with occasional valve to seat contact. This seemed to spread compound from the seat back to the valve where it could be removed. I don’t see how compound could get anywhere in the cylinder except blow out the exhaust system at startup. Is there any accounts of damage caused by residual compound, even in an oil report?
This was my concern also with this method, but it's a clever idea.
Very well done. I have question. You use the lower spark plug hole and one hand to spread the grinding compound. You use a second hand to manually turn the valve. And I don't have a third hand to hold the borescope and aim it at the valve so I can see that I am in the right place. I have the same scope you used. I have to hold the plunder to bend the scope. How do you do it?
There’s a locking ring at the bottom of the plunger. Press and rotate it to lock the scope into position.
@@jbonewitz Right, but even with the flex tip locked in place, the borescope itself is still ratting around loose in the spark plug hole. I think Mike may have used something to clamp the borescope itself in position in the cylinder.
Hi Mike, Thanks for sharing, I’m your fan.
I have a couple of questions and doubts that I would like to clarify. What about the risk of having some compounds falling into the cylinder? How to clean it eventually? I immagine that if the engine will run with some compound into the cylinder, it will be damaged in less then one hour, cylinder wall and cylinder rings gone. What about the technic of rotating the valve in the same direction? As far as I know the valve must rotate half round to the R and half round to the L, even better a quarter round R/L.
Thanks in advance for any answer which may help to clarify. Kind regards.
You just hope you get it all with a qtip apparently
It’s just a thought, actually my Lyco doesn’t need this procedure 😜
See my note above about using solvent-dampened cloth strips. Works really well.
Someone already asked, but hasn’t gotten an answer: what do you do about the grinding compound that remains on the valve seat?
See my note above about using solvent-dampened cloth strips. Works really well.
@@bertw8118 Nothing... start the engine.
Obviously some leftover grinding compound still in the cylinder…like to have seen the flushing process and how to keep the solvent out of the crankcase…rings don’t seal perfectly.
See my note above about using solvent-dampened cloth strips. Works really well.
What is the brand and model number of the borescope you used?
Vividea Ablescope VA-400. I just ordered one from Aircraft Spruce.
Quick question: how did you clean the compound off of the valve seat?
I'm curious as well. Maybe just keep wiping the valve off enough until the swabs come out clean?
9:40 explains it.
I'm wondering this too.
@@jjohnston94 that explains how to get it of the valve, which you are wiping. But you will be unable to wipe the actual seat
What works really well is to dampen a strip of soft cloth with solvent or avgas, and working through the top spark plug hole drape it over the open valve with a piece of soft (e.g. copper) wire. Pull the valve shut against the cloth strip and rotate the valve to wipe the entire sealing surface. With the right amount of pressure, you can get the cloth to wrap around the valve so as you pull it out it will wipe the entire seat. Do this 2 or 3 times and things are very clean.
I’m about to have this done to a cylinder on my Lycoming O320-E2D. The shop says Lycoming recommends doing all 4 cylinders but my last compressions were excellent (June ‘22 annual). Is doing all 4 cyl the correct action, or should we limit work to the one with the sticking valve? Thanks
Just do the one... and see.
@@apfelsnutz we did, all good now 👍
That valve looks kindda bent to me, tulip seat not seating in the head ring seat. 0:20
I’m assuming if the head were bent, he wouldn’t get the compression reading he gets at the end. And if the stem were bent, it wouldn’t slide so easily through the guide. I’m sure it’s not bent.
You didn't prepare the valve with some 3-in-1 oil and gauze pads. And you forgot about the ball bearings and 10qts of antifreeze.
Gonna try this on my 69 Pontiac lemans
OH WOW! Just wow. !! SCHOCKED!
You aviation guys supposedly advocate safety and tons of safety wire and safety concerns, yet will lap a valve in the cylinder!
Did ya notice the amount of stem and guide wear it has? (beyond worn out by any real standards)
Slop does not quite describe it!
Next . did you notice how out of round the valve even is?
Finally, now you left all that valve-grinding compound in the cylinder!
WEEEeeeeeee !
That is an interesting way to get a new bore job called "FOD" and damage ..
You just install more dirt , abrasive dirt in that cylinder then it has ever seen in its whole life!
But you saved time and money!
I have been doing valve work for years and you scared the crap out of me!
Thats airplane maintenance?
I would not do that to my lawnmower!
Yet you will now fly in this ?
A&P?- Does that stand for awesomely poor?
If you are lucky and the valve tip does not break off causing catastrophic failure with holes in the piston..next round you will be pulling the cylinder for low compression because the rings and cylinder are all excessively blow-by.
Personally, if this was my powerplant I would be documenting this and suing someone for willful neglect.
This wouldn't have been necessary if you used Marvel Mystery Oil and didn't operate lean of peak.
Marvel Misery Oil yes... operating lean of peak... of course ! Do it all the time in my Navion. {E-225}
Gary. You need to get educated. LOP is now the accepted way to operate.
@@jeffreylocke590 Ok Jeffrey - It was a joke. MMO is crap and LOP is of course a perfectly acceptable method of operation when performed properly. Yet the controversy continues...
@@I_M_Nonno why is MMO crap? what would be an alternative?
@@logisticspilot Look at the ingredients: Railroad oil (cheapest oil out there), kerosene, pig fat, red dye.
Great practice.
But hilarious. Best AP/IA on earth, preaches LOP, personal aircraft, valve damaged due to fuel mismanagement, ostensibly since previous annual (lol, not. This took hundreds of hours of screwing up) or it would have been caught at that time.
If a mike Busch customer walks in the door, they know where to find it. Hope it doesn’t hit their ass!
Hose clamp ❤😊