Continental grounds planes over crankshaft but why?!?!

[@jhaedtler]

Best explanation I have heard in a long time! Thank you Sir!

[@apfelsnutz]

You didn't mention the E-225-4 from that Navion there in your shop. I called Contenental though, and that engine is not effected... nice to fly a Navion ! Good Video...

[@w.knudsen5570]

I have 17 years industrial maintenance experience and a few years automotive. I have a curiosity of anything mechanical and I find your video interesting, informative and very well done. Thank you for your work. Subscribing

[@jumpinjack1]

Good vid from a 32 year IA, the balance weights were actually invented back in early WW2 days on the radial engines ( I think P&W) because they had a real problem with crankshafts breaking in two, this idea allowed for bigger and bigger engines.

[@planeflyer21]

Thanks for this. Subscribed! This reminded me of an old timer speaking about the old GO- aviation engines having operator (pilot) induced issues. He said pilots were used to running 2700 rpm and were hesitant to run the geared engines at the higher recommended rpms. Thus inducing issues and garnering those engines a bad rap.

[@KPMACHINE1]

Nicely explained sir! Looking forward to more technical videos. Luckily I won’t have to worry bout these crank issues cause I’ll never be able to afford anything other than my 172E.

[@patrickshaw8595]

Hmm - opposed cylinder "boxer" engines don't need counterweights. The pendulum dampers you mention are there to stop the crank from winding up and springing back at one specific frequency.

[@David-p7z9n]

If opposed cylinder aircraft engines don’t need counterweights, you should inform Continental and Lycoming engineers to save them $ millions from not installing them… A&P/IA,ASE

[@skydive1424]

Brilliant video! Now I can visualise what it’s all about. Thanks!

[@asbcustom]

I wish you all the best and Godspeed with your channel! I think you're very smart to forge your own path and not copy others. Well done.

[@navion1946]

Appreciate this Shane. I’ll be running above 2300. Usually did but now I know. Good excuse to run 25 squared 😅

[@milesj6064]

That was a good explanation of the problem complete with visuals. I am a aircraft mechanic myself, but I don't work on any Continentals, just Lycoming and turboprops. I like your approach to stuff, yes facts based are the best and don't guess, as you said you can form an opinion, but don't guess. Good job, will be checking out more videos

[@mechanicfrank900]

Good work Shane. Keep "cranking" out You Tube videos. Don't worry about "balancing" the content. Anything on aviation will be of interest. Don't forget: the sky is not the limit anymore.

[@richard8181]

I have an XP Hawke and first I have heard about this low rpm, so thanks. Since I don’t fly a lot, I always give it a good work out and don’t milk it, and not below this rpm.🫡from Australia 🇦🇺

[@David-p7z9n]

Great vid, I used to work in a part 145 engine shop doing tear down (and test cell). To remove those counterweight snap rings was challenging while the bare crank was vertical on a stand! I cannot imagine replacing one through a cylinder bore in a case while engine is installed on aircraft. A&P/IA,ASE

[@mpgofast]

As a AI for 43 years, I would have to say Manifold pressure is the key to crankshaft dampeners working correctly, If you look at most Manifold pressure gauges, the bottom of the green arc is 15", this is the minimum engine piston pressure where the engine is driving the propeller any lower and the propeller is driving the engine and the counter weights flop around and get detuned, rings flutter on the pistons and engine cooling, not good for the engine and snap rings have not changed in 50 years, one side is round and one side has a sharper edge and usually marked on the snap ring with a dot. Look at shimmy dampeners or brake cylinders for info on snap rings. education is hard to learn with out mistakes

[@DeereX748]

I stopped watching at 7:30 just to say that the engine seizing is not the worst part of it, it's what happens immediately afterward. Back in 2015, a good friend of mine crashed his V35B Bonanza after his engine seized at 500 feet AGL on takeoff, due to the exact mechanism you're describing. His engine was around 100 hrs after TBO, an IO520. One pin dropped out and the swinging counterweight cleaned out half the crankcase, taking one cylinder and both magnetos off as it went around. He had just throttled back to best climb from takeoff power, which as @mpgofast alludes unloaded the weights momentarily. Subsequent teardown of what remained of his engine showed the circlips incorrectly installed on another of the weights. He was airborne only 33 seconds after the failure, he sustained severe injuries, but his three passengers walked away with bruises. FWIW, I've flown with him many times, including twice from NC to Oshkosh, he does not mistreat his plane and flies according to the POH and his 15+ years of flight experience.

[@carlthor91]

Hopefully they show how the snapring is supposed to be installed, with the sharp edge out.

[@KeithRigby-r9c]

I suspect that the circlip is not in the groove at all, but just friction holding it in the borescope would show smaller gap between ears of clip.

[@carlthor91]

@@KeithRigby-r9c Nope, get one out and really look at how they are made. Because the balancer pins are free to move, they put the retainer in between the pin and the clip. So long as the clip is installed properly, with the sharp edge out, to grip the groove when the clip is forced into it by the pressure of the pin and retainer, against the 'SLIGHTLY DOMED SHAPE OF THE CLIP'. If that slightly domed shape is up against the groove, it can be worked out by the action of the pin and retainer. Best wishes from the far North.

[@jumpinjack1]

@@KeithRigby-r9c There is a measurement if you read the SB to check the snap ring (clip) ears for a dimension to make sure they are spread out into the groove so 'yep', you are on the right track.

[@davelowets]

Carl is CORRECT

[@bernardc2553]

Sounds like Continental dropped the ball on quality Control however any Knuckle-Buster should know what direction the piston snap ring should face ,Radius to the work ..good content

[@Supernumerary]

This use of internal snap rings within an aircraft engine is shocking. High performance, high quality automotive engines do not use snap rings. For example, piston wrist pins are allowed to float, and are restrained by “buttons” on each end of the wrist pin.

[@David-p7z9n]

It’s not the wrist pins that need snap rings on these aircraft engines, it’s the counterweights that most 6 cyl engines have. As far as the wrist pins on aircraft engines; none that I know of have snap rings (as most auto engines have). A&P/IA,ASE

[@KeithRigby-r9c]

Apparently Continental are supplying a' guage' to be used to verify correct or not installation of the circlips. If you have one or can show how it functions it would be great. 70 years an engineer and desperately curious.

[@tomp538]

Interesting video that youtube thought I might like... I was a terrestrial engine mechanic for many years. This dynamic crank counterbalance scheme is new to me. I would be interested in knowing what the problem was with the circlip installation: was it clocked wrong? was the sharp edge of the clip installed facing the wrong way?

[@oneninerniner3427]

Yup I heard it was the sharp edge.

[@midgetrace]

It is a stamped circlip. thus it has a round side and a sharp side the sharp side must be on the outside. Some how the rounded side sneaks past the grove and dislodges itself

[@oneninerniner3427]

@@midgetrace yep, sounds like that's what happens and happened, some were installed the wrong way

[@tobiaskarlsson9094]

Well the acident reporting niche is pretty much filled with blanco, fly wire and mentour, so no need for more of that. You do your thing, thing that's usually the best way of making things. It is better to be unique rather than one of many who fights over the same crowd.

[@KeithRigby-r9c]

Socialflight live with Mike Busch and Jeff Simon show the guage/tool but dont show how to use it but it appears to verify somehow the correct gap between ears of the circlip, My little plane only has an 0-200 but may fly with friends SR22 so not entirely academic interest.

[@christopherdahle9985]

Is the proper installation of circlips covered somewhere in AC 43.13 1b/2b or is it information that would be in a manufacturer's instructions, or would I have learned this in a formal A&P training program? Just starting out (14 weeks OJT) as an AMT...and this is another thing to add to my list of "Why the hell have I never heard of that?" I wonder if the orientation of circlips is an artifact of the manufacturing process...I suppose they are die stamped...or is there an engineered intention to give them a sharp edge? I have replaced circlips (on non critical applications, particularly my little planisher and the thust bearings on my band saws) and never could figure why sometimes the circlips would easily slip off my pliers and disappear across the shop while other times they would grip tightly to the pliers as desired. Anyway, seems like you have lots to teach, so I'm subscribing.

[@whirltech8031]

Yes, the sharp edge is just because they're die stamped. All engineers I know would want to remove the burrs, if it didn't cost more money (and I work with quite a few on a daily basis). The way a snap ring should "face" is determined by manufacturer instructions. Barring that, you're on your own. No specific instruction was given in my formal training that I can recall, but that training may have influenced my thinking, hopefully for the better. I will say in my experience with snaprings, having the sharp side facing away from whatever they're retaining is good for two reasons (and not the reasons you normally hear): 1) Installing with the smoother rounded side facing the component allows the snapring to expand more freely into the retention groove. If installed with the sharp side facing the component being retained, the snapring may bite into the component being retained, or the lower edge of the groove, during install and prevent full seating in the retention groove. You're normally pushing down on the snapring somewhat during install, even with snapring pliers, so having the smooth side facing the component prevents the sharp edges from digging in. Conversely, this pushing down also minimizes the sharp edge from digging into the top of the retention groove during install. 2) During operation, I figure it's best if the component that is being retained is not being chaffed on by the sharp edges. I want what I'm retaining to remain in good condition. There is normally some relative motion between retained components and the snap ring. Whereas, a properly sized snap ring often, though not always, is snug in it's retention groove, and shouldn't move around much in its groove. OJT can be very good, though seek out opportunities for formal training on topics. It's easy to pick up bad habits from OJT and not know it. FAA-approved IA seminars (they need them for continuing ed. credit) put on by community colleges are a good place to get low cost training with added potential for networking.

[@waynep343]

Snap ring installation. Critical . Never expand the snap ring farther than it takes to get it over the end of the shaft. This takes the spring tension out and causes failure. This reduces snap ring grip in or on the bottom of the groove. I can't imagine why these aren't being replaced with spirolock retaining rings. Other things that squeeze me wrong are over compressing valve springs when putting the keepers in. Or putting them in coil bind on the valve spring tester. Over stretching piston rings to get them on the piston. I totally understand that the retaining rings go on sharp side out. Am i knit picking. I build automotive engines. I went thru 6 engines in 5 years in my 66 GTO and have seen decades of engine failures during normal teardowns. Learned the expensive way of what works and what fails.

[@NavionPilot]

I know the old E-series engines (E-185, E-225, etc.) don't fall under the AD, but if you have an E-series crankshaft, I'd be very interested in seeing how the balance weights work on those, if they're any different.

[@midgetrace]

That is because the factory did not sell any new E225s

[@larz46north18]

victor-aviation : CTScan X-Ray Analysis Inspection in 3D... a good referance. CYta salute 😐

[@briankrieg5801]

I'm surprised they use a snap ring and not the dreaded spiral lock.

[@shawnnelson6146]

$850 for any jug pulling? Seems very low. Lots of Cessna 185 and 206's that use the IO-520 out here in NW Alaska.

[@ttt69420]

they remembered it was designed 90 years ago

[@whirltech8031]

Semi-genuine question: Why are they using C-clips rather than spiral lock retaining rings? I know, I know, who are we to question the almighty OEMs...

[@johnnyjohnson6771]

You did not explain the fact the issue is with the direction the snap ring is installed. Many may not understand when snap rings are manufactured they are stamped with a die-set which actually distorts the flatness of the ring with one surface edge becoming slightly rounded and the opposing edge becoming sharpened. Interestingly this distortion comes with the advantage in that the sharpened edge helps with retention provided the snap ring is installed with the sharp edge opposite the force trying to push the clip out of the groove, in this case toward your face if you are looking directly at the snap ring. Inversely, if the snap ring is installed with the rounded edge outward then this has the effect of increasing the probability the snap ring can be pushed out of the groove.

[@P_RO_]

There can also be "clocking", or orienting the gap in the lip to a specific location on the circumference of the groove, which is usually expressed relative to a colck dial. Remembering the clip is spring steel, one half of it may be subject to a force seating it more tightly while at the same time the other half can bend and slip out of the groove. Piston pin clips are often specced to be fitted at 12 oclock or 6 oclock referenced to the bore line so that the inertial force at the ends of travel are balanced and not on a single half of the clip. On these crank weights where centrifugal force acts, you'd orient the gap toward the centerline of the crank to mitigate it; 12 oclock is how that's referenced to in this situation.

[@recoilrob324]

@@P_RO_ Right. I know we've used these stamped clips for about forever...and properly installed they DO work well, but doesn't it seem odd that in such an expensive engine that these retainers would be made where it's critical HOW they're installed? As we should have learned with Col. Murphy....if it can be installed wrong, design it so that it cannot accidentally be done incorrectly. This is a clip that costs a few pennies....so we make a better one that works either way it's installed and even if they cost ten dollars to make this increases the cost by $240 which is a pittance on a $30,000+ engine.

[@P_RO_]

@@recoilrob324 They DO work well if made and used properly, so why change from success to complex which might be equally vulnerable to stupidity? Some things clearly have specs, like a cvlinder head bolt. Everyone knows how critical it is to torque these in stages and in a specific pattern, so you look it up each time. We don't need specially sized bolts to keep "Bubba" from grabbing a box-end wrench and guessing here. Nor do we need different clips. It's easy to do the job right, and you can't expect a manufacturer to design everything to be stupid-resistant. :Personally I'm more worried about a design using intentionally loose parts on a crankshaft. There's so many dynamic forces going on there that such a design invites a huge number of issues which are best avoided several thousand feet above the ground and several dozen miles to the nearest place you might be able to set down at with a decent chance of walking away.

[@whirltech8031]

​@@recoilrob324 And there is a better "mousetrap". It's called a spiral lock or Spirolox. A full 360 degrees of engagement. There's a visual indicator if it is not fully installed. The installer can tell if the free end is not fully seated into the groove, because it's not flush with the remainder of itself. And, there is no difference what orientation they are installed in, because they are burr-free. I'd hope Continental would take this as an opportunity to do the necessary qualification work and make a good product that much better.

[@whirltech8031]

​@@P_RO_ The fact that you are entirely unfamiliar with dynamic balance weights ("intentionally loose parts") on a crankshaft tells me you have little to no aviation mechanic experience. Dynamic balance weights are a very common thing on rotating assemblies on recip engines and dynamic components on helicopters (BO-105, UH-60 main rotor systems, V-22, to name a few). They are very necessary and frankly the simplest way to achieve the needed vibration damping in many applications. A better solution to circlips is needed, and it's not complex, it's simpler. I would hope they take a hard look at spiral locks as a potential drop-in replacement. Hell, you can install them by hand in most cases, and remove with a common screwdriver.

[@keithexum7312]

Nice to work on as well👍🏻

[@tsclly2377]

Probably the bane of the TSOI520D (discontinued)

[@greenbudkelly2820]

This is the Ford of aviation engine crankshafts

[@ldnwholesale8552]

So it seems this is the current batch of engines, not all of them. If it was a car they would be recalled and repaired by the manufacturer. Personally this seems to be a very crude system having some weights rattling around on the crank

[@ulfbjrtomt7165]

Thanks for good videos

[@realvanman1]

I assume the reason they didn't design a crank that can be run at lower speed is due to weight...?

[@fastmankim1]

Awesome dude we like ad,s good to know

[@michaelsamson3276]

Why didn't you mention right off the bat that that the snap ring has 2 sides? One is square and the other is rounded and some of the snap rings were put in backwards with the rounded side out.

[@95Sn95]

Seems like a piss poor janky setup, hard to believe a conventional crank like they use in the majority of every other internal combust engine.

[@wdobni]

pretty frightening stuff .... loose steel weights banging around on a crankshaft.....i'm way out of the flying addiction at my age now, but back in the day i always preferred lycoming engines....everything i read about continentals seemed to come up short compared to the same spec lycoming

[@midgetrace]

Lycoming has floating counter weights also anything like a Mooney or Cheroke 6 200 HP and up

[@YouScroob]

Has anyone ever done research to replace circlip technology with Spirolox retainers?

[@fishsticks88]

73810

[@cadude145]

Okay, that just looks stupid. Just design something that balances the engine with proper engineering. Or get a better engine.

[@Alfaspiderman84]

It is my understanding that the counter weights are there to dampen the harmonics of the prop. That is why you have a restriction on RPM. Alot of planes have a yellow arc on the tach as a "do not operate at this RPM for prolonged periods". Your description of how the counter weights work is totaly wrong. Sorry.

[@chrisjarvis4449]

snap ring pillars

[@jamesgeorge4874]

Pinning extra weight to a crankshaft seems like a disaster waiting to happen, so implementing that on an engine that may lead to falling from the sky if the crankshaft fails appears to be bad × stupid...

[@whirltech8031]

Actually very necessary in aviation applications. Remember you're not on the ground which acts as a great vibration damper in conjunction with your vehicle's shocks. The air has very poor damping, so you need ways to shift frequencies away from the resonant frequencies of the airframe or engine so that components don't literally shake themselves apart. Look up "resonant frequencies of mechanical systems". This is one reason why most attempts to use engines developed for ground vehicles on aircraft result in unreliable outcomes, unless special (and often $$$) provisions or modifications are made.

[@jamesgeorge4874]

@@whirltech8031 the need for proper balance is clear, and obvious, the method of achieving said balance is stupid,(for Continental) Tires and shocks and what the engine is bolted to have *ZERO* effect on engine balance, it is either is, or is not well balanced, and how that effects whatever an engine is bolted to, depends on what it is bolted to. Aircraft are, by nature, light and flimsy and fragile by design, and therefore Continental should have taken the time to engineer a solution that does not involve pinning weight to crankshaft, a stupid, low budget "fix" that is a glaringly obvious mistake. You don't see Lycoming horizontally opposed 6 cylinder crankshafts coming apart, or being recalled, do you ? No, because they are one piece forgings, without extra metal pinned to them.

[@chippyjohn1]

​@@whirltech8031Modern engines are far smoother running than these dinosaurs

[@wolfgangpreier9160]

Who in his delusional mind got the idea that a simple c-clip is "ok" for fast rotating engine parts?

[@tztz1949]

What is the world going to do when mechanics are gone? Fat fingered twitter feeds will be the end of anything real happening in any meaningful way.

[@apfelsnutz]

The service bulletin, in this case, is Bull Shit...sorry. I've been running my O-470 at 1900 / 21 for years.

[@Bonanza06c]

Nice Navion