Cylinder Work : Risky Business

[@phillip1115]

The joy of using 100 yr. old designed engines built by companies that think that "that is good enough" instead of "what can we improve?".

[@dabneyoffermein595]

Which manufacturer? Most engine manufacturers like Franklin and Rotax are top-notch.

[@richarddechau4200]

This is a great topic . Mike I have been an engine machinic for 50 years, I'm now 71. In that time things have changed a lot. I was one that used the STP and oil mix for years. I have built hundreds of aircraft engines but thousands of automotive race engines for the track. I worked at a engine shop that did everything. Take down to cleaning to machine work to the rebuild. The thread lubricant I use today is ARP 100-9910. We have done test on break away torque with this lub and it is far superior to any other lubricant. I'm now retired but still do engine work for the right reason and consult.

[@alanaspurling6469]

ARP has an excellent resource when it comes to fastener tightening procedures. One recommendation is use a beam type torque wrench, avoid the common click type wrenches like the plagues. A second point is that if access to measurement of stretch is not possible, the next best method would be to use an angular fastening procedure. Torque to angle is a common procedure on high end motors. I’ve built a successful 300hp 2.5 liter motor. In building this motor I used new ARP head and main studs. This motor repeatedly sees over 8000 rpm and has over 20-30 hours on it in dyno break-in, dyno tuning, and track time.

[@louisseaman8455]

For years the automotive industry has used "torque to limit" bolts and studs; these are one-time use components that are typically torqued to a specification, and then turned additionally by some specified number of degrees. I think this method is a lot better for accounting for nut-face and thread friction, but manufacturers warn against re-use of any of these fasteners. A dial indicator is VERY EASY to use if measuring the stretch of a stud when torquing a nut, but this specification isn't usually given by manufacturers, and would certainly involve a calculation most mechanics would feel very uneasy making, and most people wouldn't want their mechanic making.

[@BrianAnim]

Whoa, a savvy video in HD?! It really is a new decade! Thanks for all your videos they are great.

[@twentyrothmans7308]

Thank you, Mike, it's always informative to hear your lectures.

[@martinda7446]

I love listening to these.

[@bernardc2553]

Darn Mike sorry I missed this 1..seen your previous tq. Issues, I build HP Track Motors use ARP or Mobile Full synthetic and hardware when & where possible. . (In the field ) Good point on..DON'T STOP during final tq, Your the best & hats off for helping out fellow aviators

[@RommelADC]

Mike, thanks for giving us the benefit of your expertise and experience, another great webinar. There is so much to learn about apparently straightforward tasks. What influence does the tool have on torque? E.g. using the cylinder base wrench with the torque wrench versus using a crowfoot wrench attachment on the torque wrench. Is there a certain amount of torsional energy stored up in the base wrench before it actually torques the nut?

[@N2PPCFLYN]

Great detailed information Mike, thank you for your contributions.

[@jjohnston94]

Do we have to rely on Lycoming and Continental for torque angle specs? Could we use a comparable fastener spec (with a similar material and the same diameter and thread pitch) from car racing as a basis? Have you done any research yourself, measuring torque angle as you tighten to a certain torque, or stretch?

[@dougmackenzie5976]

Excellent presentation!! I concur in all regards!!

[@gmcjetpilot]

The Bonanza crash N16JR was not a local physician. The accident was 13 March 2006 and the two fatalities was Peter Tomarken and his wife Kathleen. Peter was the host of TV Game Show "Press Your Luck" which aired in the 1980's.

[@StjepanNikolic]

What options does the owner/pilot have? I am thinking putting touch of paint both on bolt and surface, then observe whether dots moved apart over the time.. Any ideas?

[@derheeheehee6941]

Notice Mike doesn't address what the Lycoming instructions actually say regarding lubrication procedures regarding deck studs. The through studs are specifically addressed, where as the deck studs are open for interpretation.

[@alexhuey6489]

I’m watching this thinking about changing pistons to higher compression and this is scaring the hell out of me

[@rkb8100]

Just started watching your videos and found myself totally hooked! Not a mechanic but after watching a number of the videos it’s apparent that cylinder removal is very critical. Was wondering if the engine manufacturers could install more thru bolts to secure the case when even removing a single cylinder?

[@airplanemechanic5561]

I replaced all 6 of my cylinders, I was told by an experienced (50 years) mechanic to put a washer and tighten down the thru bolts until your ready to install the new cylinders.

[@derheeheehee6941]

If you read the Lycoming instructions, they only mention lubing the through stud threads. They don't specifically mention the deck stud threads.

[@charlietame1892]

Used to work for a well known US based fastener company (Unbrako / SPS Technologies and for factory assembly their electronic torque machines do exactly what Mike suggests, they measure the "Stretch". Unfortunately they are made to fit the part and pretty expensive as you can imagine.We also made bolts for Ferrari, Lamborghini, Aston Martin etc and they wanted things like con rod bolts packed and preserved with a "Lanolin" based fluid so the torquing friction is constant when assembling their engines. Again Mike hit the bullseye with his explanation of torque friction.

[@colderwar]

I've seen a fair amount of engine damage from re use of one time stretch bolts and it's always serious. Only in a single case did the engine continue to run, although it wouldn't have run much longer - seconds probably - and needed a complete rebuild. Nothing aviation related though, I don't work on aero engines.

[@maxenielsen]

Idea: 1) Provide a blind hole running the length of the fastener. 2) Polish the end of the fastener so that the depth of the hole is exact. 3) With each fastener, provide a rod that is as long as the depth of the hole in the properly stretched fastener. When the fastener is properly stretched, the end of the rod will be flush with the fastener end. The rod probably ought to be permanently installed in the fastener. (The hole will have only a minor effect on the torsional strength of the fastener. But it will reduce the longitudinal strength in proportion to the cross sectional area it occupies.) In some automotive engines the fasteners are single-use. Torque stretches them to a specific plastic failure strain. This provides for a consistent tension.

[@discus239]

recently removed and reinstalled 3 cylinders on an IO-540 in a glasair lll, we used torque plates, and were very aware of your cautions, your examples seem to be mostly continentals, are lycomings less critical?

[@mikecrowley4275]

What do you think about using ARP Ultra-Torque fastener assembly lubricant instead of the motor oil specified by Continental or Lycoming?

[@Mrcaffinebean]

It is weird to me that torque angles aren’t used. They are very common in almost every car and it’s also commonly understood that and stretch fasteners have to be replaced.

[@brandonjones690]

Mike..thanks for sharing this knowledge. I've searched online for continuous motion torque wrench. It appears they are used in other industries. Do you know if there is such a wrench for aviation?

[@AnonyMous-jf4lc]

This is why I’ll be in experimental aircraft forever. It’s such a pain to alter a certified engine and the related procedures, progress is stifled. Funny how a guy missing most of his teeth can get a head properly torqued junkyard car engine, but an A&P is forced to follow a garbage procedure on a poor design.

[@apfelsnutz]

My sys. is to increase torque by 3 to 5% when reusing good looking studs and nuts. I use 50/50 STP/oil when assembling everything. tighten in one movement...

[@bernardc2553]

100% with ya on DON'T STOP

[@apfelsnutz]

@@bernardc2553 Thanks Bernard for the vote of confidence. I have replaced two cylinders on my E-225 [2 and 6] in the last 6 years...no problem.

[@maximolopezsr9399]

I had try to find STP , in many Automotive parts Store without any luck

[@Cavalier-lp8tr]

Can't you bring your engine up to temperature without flying in order to keep it lubricated? I've heard only 190° is necessary to dissipate moisture. Is this true?

[@maximolopezsr9399]

Mike ,I have done Hundreds of Engine , Heavy Equipment, Locomotives !Gasoline Engine,, and Aircraft Engine ,, my Constanta questions you must check your torque wrench every application ,, the type of torque wrench is my problem. Many Mechanic used micrometer type torque ,,they at the number and they think that is the torque, to me Dead weight torque wrench tester ,and test it on every application ,!,I have a big problem with the micrometer torque wrench,,

[@derheeheehee6941]

The IO-360 MM says to use food grade anti seize. The O/H manual says to use a dial beam torque wrench. If you replace one cylinder at a time, you don't need torque plates. Don't move the prop! With a cylinder removed, it is easy to replace deck studs.

[@maxenielsen]

For decades Continental and Lycoming need to have been listening to mechanics like Mike, instead of lawyers. Not disparaging lawyers - the issue is with our litigious culture.

[@gclaytony]

Very good presentation. Proper torque/bolt stretch is an issue with most industries, and has significant safety implications. For example, properly lubricated and torqued (or by bolt stretch preload) studs in flanged connections are stronger than the piping. But if improperly preloaded (insufficient torque or used studs that no longer 'rebound' from stretch), the flange will fail first, lower than the anticipated working pressure of the piping. Proper (application specific) thread lubricant like Anti-Sieze is required with one specific exception. That is the 'blue' flourocarbon coated studs/nuts - the coating has extreme lubricity and relatively tough. The other advantage over cad plated studs is that the 'blue' coated studs don't suffer from the embrittlement that results from the cad plating process. I'm still trying to get my head around the idea that anyone would think disassembling/reassembling the engine while still on the airframe would be desirable or even a good idea. Even excluding the obstructions presented by the engine mount, the idea of trying to apply torque or heavy/strenuous 'wrenching' loads while the crankcase is attached to the flexible engine mounts just astonishes me. To claim to be qualified/prepared to do a top overhaul while at the same time not having something as basic as an engine stand seems so contradictory it is tough to imagine trusting a shop/mechanic that would claim that. Even the little one man shop that I was friends with, had a 'clean room' setup for engine disassembly/field overhauls with engine stand/etc. and never did that level of work with the engine on the airframe. I guess, I would take any shop that would do that while on the airframe is a sign to run, not walk, away from that shop. IMO.

[@maximolopezsr9399]

I have spoken with LyComing Tech support about this same subject,,also the grease for the CamShaft Lou es !,,LyComing Had Not up date there practices

[@maximolopezsr9399]

Mike I have being looking for STP I Have Not it

[@zackarybowen8756]

Probably my least favorite video. I have dealt with a couple of different owners now who reference this as to why they do not want a cyl replaced/pulled for further inspection and they are terrified now. Borderline horror porn. I have replaced more than I care to remember with 0 incidents. A frame of reference is impossible to find. A ratio to the amount of cylinder work performed in a year to the amount of bad stuff that happened due to the work is impossible to calculate. However, most likely statistically insignificant at best. Ultimately I just deem their aircraft unairworthy and keep it moving, maybe they gave savvy a call afterwards :)

[@sierraone9181]

Im at 2100 hours. I am past TBO on a year 2010 (O-360) reman engine. Compressions all low 70's. Oil filter is clean no metal. But THIS freaks me out . Lol AA-5B

[@airplanemechanic5561]

if your torqueing a critical fastener, Id have your wrench checked and certified.

[@joemomma3572]

What happens to the mechanic performing the work? Any repercussions?

[@benjaminpohl]

There are countless fastener testing companies who could easily perform a torque-tension test (if someone were willing to donate an engine case for the process) and develop an appropriate torque-angle specification. Would it be legal to use it? Probably not.

[@jjohnston94]

It would probably be legal to use it to verify your torque values.

[@TheReadBaron91]

As far as I’m concerned, following the manual is the only legal way (or AC43 for minor alterations/repairs). Is there a better way? Perhaps, but too many opening legally for someone to come at you.

[@rogerfroud300]

Surely someone can commission a qualified Engineer to conclude what the torque angle should be for these fasteners? You only need to take a sample of say 10 brand new nuts and studs on an engine in a workshop and measure the angle when using the manufacturer's recommendations? Take the highest angle and use that. Even if you still use the torque method, it will give a cross check as to whether they are tight enough. You can say that you never go less than a certain angle, even if the torque was reached. If you've replaced hundreds of these, I'm staggered that you haven't done this yourself.

[@derheeheehee6941]

It's only risky if you don't follow the overhaul manual along with all applicable technical documents.

[@shoominati23]

STP is only really pertinent to old school overhead valve pushrod engines that have much larger tolerances than todays engines to decrease oil burning when they are worn, I'd think it would actually HARM modern engines.. I used to use a similar product called Motor Honey as an assembly lube to put engines together due to its ultra thick viscosity. Speaking of dinosaurs, Marvel Mystery Oil is also one that has hung on with all it had, actually it's great for getting long-dormant engines back into circulation, I suspect it might be due to the Napthalene in it breaking down gummy deposits from valve gear and oil galleries that makes it still a relevant item - and it's addition to fuel in road cars has been proven many times to increase fuel economy, if not by much, but whos not going to say no to a couple of hundred benjamins a year? especially in these trying times right now?

[@GamingwithGamerGirls]

lubricating threads and nut faces doesn't conflict with my desire for a tidy-looking engine, it conflicts with my knowledge of physics. If something is well lubricated and "slippery" when you tighten it, how does that wet, "slippery" surface not cause the fastener to loosen from the lack of friction?

[@MeaHeaR]

I thought he was a Gamé show Host Not a Physician ¿¿¿

[@bernardc2553]

Oh treat your tq wrenches like Nitro,or fine lady, I ALWAYS have a UN-touched, .re- certified calibrated "in the draw just incase..for obvious reasons. .sorry tad windy but VERY important!

[@anthonyrstrawbridge]

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