ctshepherd

My Feedback: (34)

Top of the piston with plenty of carbon buildup - yes. Inside of the piston, not so much.

I have no idea what oil the previous owner used so the buildup could have been there already. I did not tear down the engine prior to installing it on my airplane and flying it.

At any rate, the replacement parts have been ordered and they should be here sometime next week. It will be a while before I get to putting it back together as the family is taking a much needed vacation starting Monday.

ctshepherd

My Feedback: (34)

I took a closer look at the piston as it is sitting here on my bench and the signs of detonation in my eyes look to be caused more by the hundreds of particles of steel/aluminum that were floating around as the bearing was disintegrating and getting eaten up. The pits in the carbon buildup in the top of the piston had a corresponding dent from a chunk of bearing.

When I touched the engine after the flight, it was pretty cool to the touch.

ctshepherd

My Feedback: (34)

Here is another picture that I just took of the top of the piston. I did scrape some of the carbon away, but it should be fairly clear that where carbon is missing, there is an impact point from bearing metal that caused it to flake off.



Moderator enlarged the picture . . .

av8tor1977

My Feedback: (6)

I understand what you are saying about impact damage. It is hard to tell, but that particular pattern in the carbon on the dome of the piston I have often seen in engines that were detonating. Take a magnifying glass and a bright light and have a good look at the spark plug too.

To me, the carbon under the piston dome indicates either a poor quality oil, or some pretty warm running temps. I run premium fuel and good oil in my engines, whether they call for high octane fuel or not, and of course good cooling is paramount. The underside of the piston dome is a good inspection place to see how a two stroke engine has been running if no other obvious clues "jump out at you".

AV8TOR

Valve floater

Looks like a normal amount of carbon in an engine with moderate run time.That amount of carbon should not affect the engine at all. When i was using Bel-ray MC1 at 50:1 this is about the amount i had.Jodi told me it was not that important to even clean the top of the piston much at rebuild.The engine was tuned to have the clearance with the carbon on top.I`m using Stihl Ultra now. I won`t be surprised to find this amount of carbon when i inspect my current engine in about 100 hrs. Won`t hurt anything. I believe you have to go by the plug color to see what the engine is doing.

BadAzzMaxx

The engines failed because of low quality needle bearing, The oil used and mixed right had nothing to do with it.

If you look at most of the post about China made engines, 90% of the failures are from needle rod bearing failing.

When i had the problem with some engines I sold about three years ago, I took some of the bearing to a IKO bearing dealer and they had a on engineer there.

He was not there when i left the bearing and did not hear anything for about two weeks and thought that was a dead end, About a month later I get a call from him about them.

He had did some testing and told me none of the needles in the bearing were treated the same, Only the surface was hardened and it flaked off just like chroming would flake off a old style car bumper.

Gave me a lot of information about needle bearing, They are not all the same, Some are made for two stroke gas engines and others are made for different applications.

Not treated enough and they will fake, Treated to hard and they will break up into little peaces.

Now, why will the engine companies in China not get better bearing made outside of China, Had a conversation with a owner of a company in China about this and was told that if a product they need for there manufacturing is made in China they have to get it from China and can not go outside of China to get it, True or not i do not know.

Milton

w8ye

My Feedback: (16)

Good post Milton

av8tor1977

My Feedback: (6)

I was not speaking of the carbon on top of the piston, other than it appearing to me as though it might have experienced detonation. I was speaking of the carbon on the underside of the piston top, inside the piston. That amount of carbon inside the piston is what would have me curious about the engine's past...

The quality of the Chinese bearings is certainly in question. My point is only that detonation will ruin any rod bearing, and can be a problem in two strokes sometimes.

AV8TOR

Valve floater

OK. These are pictures of the broken piston (nick by ring area by needle passing thru) Never took the wrist pin off until now for this picture. Had over 300 to 400 flights on engine. DL-50. Using Bel Ray MC-1 at 50:1. Also, i replaced the crank bearings out at around 50 flights ago.Cleaned the top of the piston for the fun of it at that time. So top of piston carbon in the pic`s took about 50 flights to build. I should have replaced whole crank but i didn`t. That`s what caused the failure. But i have a new DLE-55 from VV so i`m not going to fix it. As you can see hardly any carbon on inside of piston. Only oil stained.Also the ring is stuck by the nick area.

jedijody

My Feedback: (1)

Ididn't say Klotz oil caused the bearing to fail, my comment about Klotz was a generalization and I will stand by it. I've done a fair amount of oil testing, and Klotz was one of the oils I tested. To qualify that, I don't test oils the way a typical modeler uses them, 10-15 minutesrunning then off for an hour, 3-4 times in aweekend, for only 1/2 the year.My oil tests were done with heavily loaded engines running at or near peak high temperature (150* C), running WOTfor8-10 hours at a time until a minimum of 200 hours is accumilated orthe engine quits. Theengines got no attention after they were tuned for peak RPMexcept maintaining the fuel tank. I didn't like what I saw with Klotz oil but it may work fine for those engines that don't work for a living. There are MUCH better oils.

Also as Av8tor mentioned, the pictures show evidence of hot running or poor oil or both. The oil is coking out and plating on the piston skirt, if you want toknow if you're running hot, look at the wrist pin. If it's purple or blue it's been running too hot.

jedijody

My Feedback: (1)

The first pictures are 200 hrs on Stihl HP Ultra, the 3rd is 500 hrs on the same.</p>

av8tor1977

My Feedback: (6)

JEEZ what an ugly engine!! (The Klotz pictures.)
Say Jodi, you wouldn't happen to have a pic of the underside of the piston dome/head of the ones that ran on Stihl Ultra HP would you?

AV8TOR

blikseme300

My Feedback: (118)

Jody,

Wow!

What is the part number of the Klotz you tested? I have not tested they way you have but after many run hours I see no evidence of the coking out or build up on the skirt on any of my engines.

I am considering switching as I cannot get Klotz KL-305 locally but am interested in which specific oil you used in your testing.

The pictures you posted are quite compelling and sure beats any description.

Bliksem

captinjohn

The engines failed because of low quality needle bearing, The oil used and mixed right had nothing to do with it.

If you look at most of the post about China made engines, 90% of the failures are from needle rod bearing failing.

When i had the problem with some engines I sold about three years ago, I took some of the bearing to a IKO bearing dealer and they had a on engineer there.

He was not there when i left the bearing and did not hear anything for about two weeks and thought that was a dead end, About a month later I get a call from him about them.

He had did some testing and told me none of the needles in the bearing were treated the same, Only the surface was hardened and it flaked off just like chroming would flake off a old style car bumper.

Gave me a lot of information about needle bearing, They are not all the same, Some are made for two stroke gas engines and others are made for different applications.

Not treated enough and they will fake, Treated to hard and they will break up into little peaces
Very good post Milton....probably why the DLE 20cc engine rods are failing! Capt,n

Tired Old Man

My Feedback: (1)

The 3 picture post of the failed engine show clear evidence of hot running and oil failure. The black underside of the piston indicates hot running. When they run within mormal temp levels that black color isn't there. Just a light, see through brown color. The plated piston skirts are absolute examples of an oil failure. Plating of the oil is the last step of oil degradation before piston melt down.

Ya'll might want to listen to Jody more than you ever have before. His engine experiments and research have risen to a new level, one that few will ever be able to achieve.

jedijody

My Feedback: (1)

All of them.

hanko

Klotz recomends the model lube type for the type of engines we use. Ive run it for years with excellent results. robably a bad bearing from the get go. I had a crank break and so did a buddy of mine. Thats the only issue Ive had with Dle engines

esacco

My Feedback: (30)

Hi jody! Thanks for all the help and information here. It is very nice of you. Question, I have 10 qts of mobil 1 2t is that also ok? I have been using this for years and it is super clean and works great. Thanks for your imput

Tired Old Man

My Feedback: (1)

Mobil 1 is another of the better oils for our uses. The better oils that have been subjected to testing have a J.A.S.O. approval rating. The Japanese found that the rating system being used here in the U.S. was more appropriate for water cooled engines and failed to provide useful reference when selecting oils for air cooled engines and therefore came up with the J.A.S.O. methodology. There is essentially three performance levels, with the highest ending with the letter "D".

Note there is no requirement for an oil manufacturer to rate their products, so some very good oils do not carry a rating. Also note that anyone can recommend their products for any purpose. There is no requirement they be accurate in their recommendation because there is no liability for being wrong. Some oils have had their day in the sun, but sunset has long past with the switch to gas engines. There are much better products available for our purposes that are also more widely available. BTW, any oil using a castor based oil in any quantity is bad ju-ju for your gasser.

If you want to gain a "bird's eye" view of what the better oils are, take a look at what the professional motorcycler racers are using on their aircooled engines. From that point you have to determine if their oils require frequent engine tear downs for cleaning or parts upgrades after racing. Some of the racing oils do not have detergents because the manufactueres anticipated the user, involved in racing' will have more internal involvement with their engines. As Jody already mentioned, most of you don't and won't have a clue about the thermal laods your engine is subjected to, and a 10 or 15 minute engine run will never, ever, experience the full potential of either your engine or the oil used in it. But armed with only the smallest amount of visual information you'll defend your oil selections all the way to the death of your engines.

jedijody

My Feedback: (1)

All dat is dead nuts on Old Man.

Only thing I would add is to be careful when choosing motorcycle racing oils. Many, if not most, modern crotch rockets are liquid cooled and do run at lower temps than their air cooled cousins. Also, with anything marketed for racing applications, as T.O.M. mentioned, the engineers expect you'll be inside regularly to inspect, clean, repair, and refreshas needed. Oils can give great performance as far as lubricating goes for short periods but still require their residues be removed on a regular basis.There are some exceptions to this but unless you want to spend the money on engines and oils to test and form your own conclusions, one is better off listening to the more experienced and appropriately positioned in professions to know the difference.

I rarely get into the oil BS on forums because most just want to argue from a perspective that doesn't really put an oil to test. There many oils that will work great in this application where the vast majority of engines are lightly loaded, infrequently used, and die prematurely of other user induced causes, not oil. In my experience, the best oils for our application are marketed and sold by the perspective manufacturers of professional outdoor, air cooled equipment such as chainsaws, leaf blowers, string trimmers and the like. That equipment gets used year round, ridden hard and put away wet right out of the box for years without even thinking about looking inside.

Tired Old Man

My Feedback: (1)

I've been trying to educate about lubricants for years to no avail. Hopefully you will have better luck reaching the masses than I did. Most people use an oil because their engine dealer sold it to them, never considering their engine dealer makes money on repairs and replacements. Some of those dealers are coming around and changing the oils they recommend, but not all.

If only the users would bother to ask their dealers and engine manufacturers how much run time they've devoted to oil testing and analysis they might begin to understand. You know how much run time I put into it, and you're now on a similar path. Oil performance for our purposes has little to do with what is written on the brand label. The label statement is only the foundation for selecting those products to be further tested, with many being discarded during and after the test processes.

Valve floater

You will have to pry this bottle of oil from my dead fingers.LOL

av8tor1977

My Feedback: (6)

Thank you TOM and Jodi for verifying my comments about oil, carbon, and temperature on the engine in question in this thread. Can't get better "back up" than you guys!

AV8TOR

Whistling Death

Ha Ha, good stuff.

blikseme300

My Feedback: (118)

TOM & Jodi,

Interesting and sobering information here. Not the typical oil wars thread here.

Thanks for all your experienced inputs here.

Bliksem