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Thread: Oil analysis and sticking exhaust valve?

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    nightflyer's Avatar
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    Oil analysis and sticking exhaust valve?

    Iím curious to see if anyone else has noticed a trend in their oil analysis and sticking exhaust valves. I would occasionally get a slight shutter during cruise ever since my trip to Idaho in May. I just thought the engine was digesting some water since I had pulled a small amount of water out of the fuel tank when I sumped it during preflight. I only pulled water out once though. I just did a trip to Utah last month and I was getting some morning sickness on the first start-up and that was the first time Iíd had any issues on start up. I was probably in denial but I attributed it to the high altitude and cold weather. I had a couple of more shutters on the last leg home and then the the valve finally stuck for good on the first start up after my trip when I went to warm up the oil for an oil change. I certainly learned some lessons with what a sticking exhaust valve feels like now. My oil analysis had been showing high chrome which initially we thought was because the engine sat for five years during restoration and had some corrosion but it got worse as I ran the engine. Iíve attached my latest oil analysis to see if anyone has any ideas if there were clues to my sticking valve from that. It was the number 3 cylinder on a O-320A2B 160hp. I use Phillips XC 20W50 with Camguard, and I donít used MMO in the fuel or oil. The engine was built in 1982, had 1600 hours on it, and was never overhauled. Itís now at LyCon getting getting itís long awaited overhaul. Donít be like me and let it get this far when you get morning sickness. Iím extremely fortunate that the valve decided to stick for good after I got home and not on my trip.
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    Thanks for posting the analysis. I often wondered how the dirty, off airport environment that a lot of our cubs live in effects the numbers. Do the numbers look different in a Super Cub that is used a couple times a week to play on the river or in the canyon compared to a Cherokee that flys from pavement to pavement?
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    I had read somewhere that gases getting past the rings into the crankcase can cause crud to build on the exhaust valve stems. Blackstone said that the the high chrome could be due to ring wear so maybe that’s what was happening. I guess we’ll find out more after they open up the engine and take a look.

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    Had you ever done the Lycoming SB regarding the valve guide checks? I think that’s recommended every 400 hrs? Not sure.

    Rich
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    How long were you doing the oil report for prior to the stuck valve?


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    My engine is in the OH shop now due to a stuck valve causing the cam to degrade.

    1978 engine, just under 1,500 hour total time, but I have been putting 100 hours a year or so on it for four years.

    The only change I made is that I have been doing less high power cruising on my plane the last two years as I have been working from home more than I had previously. Around here I lope around slow looking for critters and such, heck, the cabins are only 12 minutes away!

    I will be more religious with Marvel Mystery Oil. I was using Cam Guard, but not on every oil change. Phillps XC 20-50 oil on Lycoming O-540.

    FYI: I do lean my engine, so carbon build up has never been a problem.

    Knowing what we can do to prevent stuck valves would be helpful.
    I don't know where you've been me lad, but I see you won first Prize!

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    Quote Originally Posted by Richgj3 View Post
    Had you ever done the Lycoming SB regarding the valve guide checks? I think thatís recommended every 400 hrs? Not sure.

    Rich
    Not since Iíve owned it but Iíll check the logbooks. The 160hp STC was done around 500 hours ago so that included a top over all with refurbished cylinders.
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    nightflyer's Avatar
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    Quote Originally Posted by RaisedByWolves View Post
    How long were you doing the oil report for prior to the stuck valve?


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    The last analysis in that report was taken from the oil I drained the day the valve stuck.

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    Quote Originally Posted by aktango58 View Post
    My engine is in the OH shop now due to a stuck valve causing the cam to degrade.

    1978 engine, just under 1,500 hour total time, but I have been putting 100 hours a year or so on it for four years.

    The only change I made is that I have been doing less high power cruising on my plane the last two years as I have been working from home more than I had previously. Around here I lope around slow looking for critters and such, heck, the cabins are only 12 minutes away!

    I will be more religious with Marvel Mystery Oil. I was using Cam Guard, but not on every oil change. Phillps XC 20-50 oil on Lycoming O-540.

    FYI: I do lean my engine, so carbon build up has never been a problem.

    Knowing what we can do to prevent stuck valves would be helpful.
    I usually cruise around 2400 to 2500 rpm. I was surprised that it was the the number 3 cylinder though and not one of the front ones that run cooler CHT’s.

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    My two cents. I did a top overhaul on my engine and used the Phillips 20-50XC as recommended for break in by the cylinder company. The good thing about this is you can just keep running the Phillips after break in. At around 250 hours on the cylinders on a trip to Alaska I had a sticking valve out of Dease Lake. That will get your attention real quick! I came back and landed and looked things over but did not know what was going on since I had never experienced this before. I could not duplicate it and continued on. I got to Ultima Thule Lodge and had it happen again one morning. I told Paul about it and he said it sounds like a valve sticking and asked what engine oil I was using. He told me he only runs straight weight Aeroshell and told me to change oil. I continued fighting this sticking valve for another 100 hours thinking how could it be the oil and I had a few cases of oil to use. It seemed if I did a long through warm up I did not usually have a problem, then one day coming through the gorge on top and it started doing it after a flight back from Idaho and I decided this has got to be fixed. I switched oil to Aeroshell 100 plus and it never did it again. I will never use Phillips again.
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    Quote Originally Posted by Mauleguy View Post
    My two cents. I did a top overhaul on my engine and used the Phillips 20-50XC as recommended for break in by the cylinder company. The good thing about this is you can just keep running the Phillips after break in. At around 250 hours on the cylinders on a trip to Alaska I had a sticking valve out of Dease Lake. That will get your attention real quick! I came back and landed and looked things over but did not know what was going on since I had never experienced this before. I could not duplicate it and continued on. I got to Ultima Thule Lodge and had it happen again one morning. I told Paul about it and he said it sounds like a valve sticking and asked what engine oil I was using. He told me he only runs straight weight Aeroshell and told me to change oil. I continued fighting this sticking valve for another 100 hours thinking how could it be the oil and I had a few cases of oil to use. It seemed if I did a long through warm up I did not usually have a problem, then one day coming through the gorge on top and it started doing it after a flight back from Idaho and I decided this has got to be fixed. I switched oil to Aeroshell 100 plus and it never did it again. I will never use Phillips again.
    This is interesting. One recent conversation about oil it was mentioned that the 'plus' additive, a fairly new thing, is much better for your engine than the older versions. I was told that one could run the 'plus' oil, or run an additive like Cam Guard which amounts to the same thing.

    I believe when I get my new engine I will be going back to strait weight oils. Used it on the cub for years...

    Thank you for the information and experience; did you need a new seat cushion?
    I don't know where you've been me lad, but I see you won first Prize!
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    I've never had a valve stick when wearing red socks. Wear red socks.
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    Quote Originally Posted by Mauleguy View Post
    My two cents. I did a top overhaul on my engine and used the Phillips 20-50XC as recommended for break in by the cylinder company. The good thing about this is you can just keep running the Phillips after break in. At around 250 hours on the cylinders on a trip to Alaska I had a sticking valve out of Dease Lake. That will get your attention real quick! I came back and landed and looked things over but did not know what was going on since I had never experienced this before. I could not duplicate it and continued on. I got to Ultima Thule Lodge and had it happen again one morning. I told Paul about it and he said it sounds like a valve sticking and asked what engine oil I was using. He told me he only runs straight weight Aeroshell and told me to change oil. I continued fighting this sticking valve for another 100 hours thinking how could it be the oil and I had a few cases of oil to use. It seemed if I did a long through warm up I did not usually have a problem, then one day coming through the gorge on top and it started doing it after a flight back from Idaho and I decided this has got to be fixed. I switched oil to Aeroshell 100 plus and it never did it again. I will never use Phillips again.
    Interesting, Iím going through something similar. CubCrafters recommends 20w50 on the carbon cubs. I have a 66 hr engine with the cylinders off due to excessive oil consumption. The engine manufacture says 100w and 15-50 aeroshell in the winter with 100 for break in.


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    I recommend listening to Mike Busch's 30 min talk on sticking valves. Not due to carbon, but lead-Oxy Bromide which is from the tetra-ethyl lead added to 100LL. Apparently from running the engine too cool, not too hot!

    https://www.youtube.com/watch?v=m_Vz6v9tsgk
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    What supercub9675 said.. My new Millenium O-200 cylinders had 4 excessively leaky exhaust valves with one sticking at about 250 hours. Reamed all the guides, lapped valves in place and watching to see what happens going forward. Superior can’t explain why I didn’t have this problem on my original TCM cylinders which ran fine for 25+ years. Several shops suggest valves and seats on new cylinders have been a problem and they routinely grind them before install. Lead was high on my oil analysis.

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    I should add one more thing that I found interesting. I ran those cylinders for another 750 hours with no valve sticking (a little over a 1000 hours on them with 10.5-1 pistons). At a conditional inspection I notice two of the four cylinders had low compression so I ran them a little more with it not getting any better (both were below 60). I decided to pull both of them and take them to Premier Aircraft in Troutdale and have Jim look at them. I called him up and asked what he found and he said they both looked good that he did not find a smoking gun as to why compression was low. He asked what oil I was using and I told him 100 plus, he said that he had seen this fairly often now. His theory was that the cylinders get to slippery with the "plus" and recommended going with straight weight 100 aeroshell summer and 80 winter. He said if the airplane is flown regularly the plus is of no real benefit anyway. So that is what I have done for all my aircraft since. YMMV
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    BC12D-4-85's Avatar
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    Stuff from combustion (carbon-lead-whatever oil additives) can bake out on hot parts. Changing oil more frequently gets rid of stuff still in suspension large micron filters can't remove. Periodic oil analysis run during an oil change cycle can show the gradual increase in byproducts, but who has the time and money for all that? Some commercial equipment operators do, like generators and fixed power plants, or long haul trucks or boats.

    Only an opinion: Just because 50 hr or more oil change intervals are available with some filtration systems doesn't mean every engine should go that long. If the oil looks contaminated before that interval it probably is to some degree so dump it. Oil's cheap compared with repairs.

    Gary - I use Shell 80 Plus as my annual flight times have decreased lately.
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    Quote Originally Posted by Mauleguy View Post
    I should add one more thing that I found interesting. I ran those cylinders for another 750 hours with no valve sticking (a little over a 1000 hours on them with 10.5-1 pistons). At a conditional inspection I notice two of the four cylinders had low compression so I ran them a little more with it not getting any better (both were below 60). I decided to pull both of them and take them to Premier Aircraft in Troutdale and have Jim look at them. I called him up and asked what he found and he said they both looked good that he did not find a smoking gun as to why compression was low. He asked what oil I was using and I told him 100 plus, he said that he had seen this fairly often now. His theory was that the cylinders get to slippery with the "plus" and recommended going with straight weight 100 aeroshell summer and 80 winter. He said if the airplane is flown regularly the plus is of no real benefit anyway. So that is what I have done for all my aircraft since. YMMV
    Were they put back on without any rework and did the compression come back up after going to 100?

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    Quote Originally Posted by supercub9675 View Post
    I recommend listening to Mike Busch's 30 min talk on sticking valves. Not due to carbon, but lead-Oxy Bromide which is from the tetra-ethyl lead added to 100LL. Apparently from running the engine too cool, not too hot!

    https://www.youtube.com/watch?v=m_Vz6v9tsgk
    You need to check your link.

    Too cool CHTs, EGTs, or oil temps?

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    Quote Originally Posted by 40m View Post
    Were they put back on without any rework and did the compression come back up after going to 100?
    No I had them overhauled with new everything from what I remember, I know for sure they had new exhaust valves because I remember thinking that the price of overhaul was probably the last time I do that.
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    Quote Originally Posted by Mauleguy View Post
    My two cents. I did a top overhaul on my engine and used the Phillips 20-50XC as recommended for break in by the cylinder company. The good thing about this is you can just keep running the Phillips after break in. At around 250 hours on the cylinders on a trip to Alaska I had a sticking valve out of Dease Lake. That will get your attention real quick! I came back and landed and looked things over but did not know what was going on since I had never experienced this before. I could not duplicate it and continued on. I got to Ultima Thule Lodge and had it happen again one morning. I told Paul about it and he said it sounds like a valve sticking and asked what engine oil I was using. He told me he only runs straight weight Aeroshell and told me to change oil. I continued fighting this sticking valve for another 100 hours thinking how could it be the oil and I had a few cases of oil to use. It seemed if I did a long through warm up I did not usually have a problem, then one day coming through the gorge on top and it started doing it after a flight back from Idaho and I decided this has got to be fixed. I switched oil to Aeroshell 100 plus and it never did it again. I will never use Phillips again.
    I had two stuck valves on my Lycoming O-540 not too long after that started making metal. Called a very well known performance engine shop and told them the same, the first thing they asked is ďAre you running Phillips ?Ē I replied yes with cam guard their next reply was ďStop running Phillips use AeroshellĒ They had no scientific explanation but according to them, almost to an engine, the ones with valve sticking issues were running Phillips. Engines running aeroshell were generally not sticking valves. I have no ties to either Phillips or Aeroshell just my experience. I went ahead and had the overhaul done 300 hrs later all still good. I wonít run Phillips in anything I own either.


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    Gotta love the science of opinion.

    https://youtu.be/gCMzjJjuxQI
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    Oil analysis and sticking exhaust valve?

    Quote Originally Posted by stewartb View Post
    Gotta love the science of opinion.

    https://youtu.be/gCMzjJjuxQI
    Definitely my opinion based on non scientific stats of one shop. Could be totally unrelated to why I had valves stick, but hey they warranty my engine so I listened.



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    After 1800 hrs, I had 3 stuck valves on my Lycoming O-360-A2A (nitride cylinders) & decided to get the cylinders overhauled. 400 hrs later, I had 2 more stuck valves & so in this coronavirus year, I went ahead & got the engine overhauled (& all new nitride cylinders). I put the 2200 hours on the engine over the past 8 years, averaging 200-300 hrs/year, so no moss grew under my bushwheels. I only used Phillips 20-50xc with Camguard. I lean the engine & have never had carbon buildup. Iím operating at high density altitude and the cylinders do run cool (300-330 degrees) in the winter. My (now former) mechanic didnít know how to do the Lycoming wobble test, which would have been a useful diagnostic tool. Also, at the overhaul, the shop found that several of the cam lobes were spalling, but none of the spalled lobes were associated with any of the stuck valves. Both intake and exhaust valves were among the six-total stuck valves. I tried using MMO in both the oil & fuel after the valves started to stick, but maybe I didnít use it long enough, because the problem didnít get resolved. I was also disappointed with Camguard, which didnít seem to prevent any of the problems. Iíd never had a stuck valve until all the ones that happened to this O-360. Now that the engine is overhauled, Iíd sure like to operate it so I donít get more stuck valves down the road.


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  25. #25
    BC12D-4-85's Avatar
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    I came into aircraft ownership (early-mid '70's) without having much experience with uncompounded mineral oil. I was told to use a straight weight ashless dispersant oil containing a pour point depressant after break-in was completed. So I did. The first valve sticking or cam spalling I encountered was after switching to a multi-grade oil. Same for the second. I was winter flying/trapping lots and the cold weather performance encouraged me to try it. I went back to straight weight with no valve issues so far on several engines.

    Here's my question: What were operator's experience with pre-compounded or multi-viscosity oils? Was valve sticking as common then as now? I'd like to learn something if some can share. Also 80/87 was common then for low compression engines.

    Gary
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  26. #26
    Gordon Misch's Avatar
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    Windy, what, if anything, are you doing different now to try to avoid that problem? I haven't had any sticky valve problems (except the Wisconsin engine on my baler), but - - -
    Gordon

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  27. #27
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    Quote Originally Posted by Gordon Misch View Post
    Windy, what, if anything, are you doing different now to try to avoid that problem? I haven't had any sticky valve problems (except the Wisconsin engine on my baler), but - - -
    I just this week switched from Type M mineral to the regular Phillips 20-50xc for the winter. Iíll also be switching to fine-wire spark plugs. The sticky-valve engine used REM37BY plugs its whole life, which have a cooler spark. I donít know if it will make any difference on sticking valves, but I shouldnít have to be replacing spark plugs for a while.
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    Well I screwed up that link I cited! Here's the proper address/link. (Mike Busch discussion on sticking valves).

    https://www.youtube.com/watch?v=7ohsVvYbAaQ&t=1847s

  29. #29
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    Interesting discussion. I ran my factory reman to 2400 hrs before it was low on compression on one cylinder and failed the wobble test (loose guides) on all 4. New Lycoming cylinders with LyCon flowing them and doing their valve work. I have always used Phillips 20w50 and Camguard. I haven't ever had a stuck valve. I am curious after Windy's comment about her mechanic not familiar with the wobble test if it would show a tight valve. My understanding of the wobble test was premature wearing of the exhaust valve guides but was told recently by a cylinder overhauler that the present guide material has made that issue go away up to TBO anyway.
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    I would blame 100LL use way before I would blame the oil. 100 LL has 4-5 X the lead in the fuel than the engines where designed for. Using MOGAS/MOM/leaning the mixture will help. The problem with trying to keep cylinder temps high is now you can cause accelerated valve guide wear. One thing not mentioned, the rings are not the only place you see blow-by. As a valve guide wears you will start to see that gray milk build up on the exhaust valve. If you get in the habit of pulling valve covers every 100-200 hours you will see what is normal. When you notice a big change consider doing a wobble test. No science in any of this just things I have noticed.
    DENNY
    Last edited by DENNY; 11-07-2020 at 03:51 PM.
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    Quote Originally Posted by aktango58 View Post
    This is interesting. One recent conversation about oil it was mentioned that the 'plus' additive, a fairly new thing, is much better for your engine than the older versions. I was told that one could run the 'plus' oil, or run an additive like Cam Guard which amounts to the same thing.

    I believe when I get my new engine I will be going back to strait weight oils. Used it on the cub for years...

    Thank you for the information and experience; did you need a new seat cushion?
    The new Phillips stuff is basically just the Lycoming slick 50 additive used to prevent excessive cam/lifter wear.
    DENNY

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    "Cooler spark" A cool plug has a shorter center insulator so the plug runs cooler, not the engine or combustion. Fine wire plugs resist fouling in spite of running cool(or oily) they don't change anything.
    What's a go-around?

  33. #33
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    At some point in this discussion I am hoping we have a chemist.

    With the change in base metals used in fuels over the last few decades, and the changes in oil additives, is it possible that we have some chemical reaction that is increasing the valve sticking problem?
    I don't know where you've been me lad, but I see you won first Prize!
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  34. #34
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    Quote Originally Posted by aktango58 View Post
    ...With the change in base metals used in fuels over the last few decades, and the changes in oil additives, is it possible that we have some chemical reaction that is increasing the valve sticking problem?
    That's sorta' what I asked in #25...has valve sticking in GenAv always been a problem? How about the 1950's and '60's? Anyone recall that flew then? I didn't have a problem (valve sticking/cams) until the mid-'80's and that was when I switched to a multi-vis 15W-50 in small Lycomings. The Conti IO-520's I flew ran TBO one after the other but on straight weight.

    Gary

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    I know there are folks who are not a fan of Mike Busch on this forum. The dude admits he is more of a data analyst. Points of random data exists. If we can organize the data, then we have information. If we read the information, we can gain knowledge and which leads to wisdom....or maybe leads to improved reliability of Lycoming engines. It seems to me like Engine Data analysis is Mikes strong suite. The facts below are his, not mine. Below is a synopsis of the data Mike shares in that video link in post 28 and this AOPA article
    https://www.aopa.org/news-and-media/...intance-valves

    -Cool running engines have more sticky valves than warmer running engines.

    -Valves stick due to buildup of deposits on the valve stem inside of the valve guide.

    -Laboratory chemical analysis by a petrochemist from Exxon has been performed on valve stems.

    -TEL is used as an octane booster in 100LL fuel requires a scavenging agent.

    -This lead scavenging agent that is added to help avoid fouled spark plugs.

    -A chemical reaction during the combustion event produces a byproduct of the scavenging agent called Lead OxiBromide.

    -The Lab analysis showed that Lead OxiBromide is primarily the source of the buildup on the stems of stuck valves.

    -Engine Monitor will show a rough running engine from a sticking valve to produce an EGT value that is not normal. As the engine warms and the stuck valve loosens, the EGT will indicate normal.

    -Lead Oxibromide that remains as a gas above temps of 1100F.

    -After the combustion event we want the Lead OxiBromide to remain gaseous (above 1100F) to pass harmlessly out the exhaust.

    -The hotter the temp, the faster the lead is scavenged.

    -A cooler surface will condense these gases and over time form hard deposits on surfaces they contact, like a valve stem of an open exhaust valve.

    -Sodium filled Lycoming valve stems run cooler than Continental valves and the chances of a stuck valve is more likely with them.

    --Mike thinks that the conventional wisdom that the carbon deposits on the valve stem inside the valve guide from oil contacting the hot stem and carbonizing the oil is wrong.

    What Mike says to do....

    -Since CHT is the best indicator for Valve stem temperature, keep the CHT's between 350F - 400F to avoid Lead Bromide buildup on your valve stems.

    -Lean aggressively on the ground and low power operations to keep combustion temps as high as possible.

    Click image for larger version. 

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    Last edited by bcone1381; 11-07-2020 at 04:34 PM. Reason: Clarify
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  36. #36
    skywagon8a's Avatar
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    While there definitely has been a change in the metal alloys involved, it seems that the issues of sticking began as 80 oct began to disappear and more planes needed to start using 100/130 oct. Increased lead build up on the valve stems. When the 100/130 was discontinued and 100LL came upon the scene, the lead ppm was cut in half but was still more than the 80 oct. The wobble test was to indicate when excessive clearances between the valve and guides started appearing as an issue. A metallurgical issue.
    N1PA
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    Click image for larger version. 

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    I know this is just an O-200, but when I got home and pulled the exhaust, this is what all 4 exhaust ports looked like. All the guides had crud, as did the seats. I operated this airplane for 20+ years before we overhauled the engine and never had a problem, maybe 2500 hours. After break in I ran the same we I always have, hard and lean. Again, this is from about 250 hours of operation.
    Last edited by mam90; 11-07-2020 at 06:02 PM.

  38. #38
    BC12D-4-85's Avatar
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    Ok thanks Pete for the historical perspective. Can we assume there's two problem scenarios (https://bondline.org/wiki/Valve_Wobble_Testing)? The valve to guide clearance increases via wear and is noted by the wobble test. Or, the valve to guide clearance decreases (and maybe after the previous scenario) due to deposit buildup. Both are not good.

    Gary
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  39. #39
    BC12D-4-85's Avatar
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    "I know this is just an O-200, but when I got home and pulled the exhaust, this is what all 4 exhaust ports looked like. All the guides had crud, as did the seats. I operated this airplane for 20 years before we overhauled the engine and never had a problem, maybe 2500 hours. After break in I ran the same we I always have, hard and lean. Again, this is from about 250 hours of operation."

    Was the oil consumption post break-in similar pre and post overhaul? Were the fuel and oil used the same?

    Gary

  40. #40

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    Everything the same Gary, except probably slightly more 100LL post overhaul due to the Alaska trip. Harder to find mogas enroute. Trusted engine shop said he suspected improperly ground seats. He said he never installs new cylinders anymore without checking as he’s seen way to many. If I have any more problems I’ll pull the cylinders and take them to him.
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