Flyfalcons

freeonthree, this is the part where you take a step back and listen to the members with experience. You don't just arbitrarily mix your synthetic oil at 100:1. You absolutely must mix the oil at the oil manufacturer's recommended mix. Amsoil 100:1 gets mixed at 100:1 but Amsoil 50:1 must get mixed at 50:1. Other synthetics might need to be mixed at 32:1 or some other ratio. That is how the oil is designed and if you want your engines to last, that is how you must mix it. And yes, thinning your oil mix because you are getting some oil residue on the belly is an extremely bad idea.

altavillan

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I pulled one of my engines rings so I can run my oils recomended ratio of 114 to 1 I'm guessing the bottom ring was the one trying to exit the exhaust port so it obviously isn't needed or wanted. RTK promised to loan me an engine if I need to borrow one

Tired Old Man

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Going by the jug you showed me today you need at least half of one Just to be a snit, I'd send that one back to see if you can get a warranty replacement. You're already out the jug so why not give it a shot?

freeonthree

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Well, tell me this, 100:1 is on every bottle of oil, on the chart. What machine would run 100:1 ? Im not going to switch, I think my engine loves it. And now that I have seen Gregs 4 year old plug, Im not worried in the slightest. As a matter of fact, I bet I get at least 10 years out of this engine before it needs rebuilding. We'll just have to wait and see. I've been flying for over 5 years, and I havn't had an engine failure yet, except for the occassional bearings in the nitro engines. I sure wont miss doing that. All my 4 strokes still have the origional glow plugs in them too, so I guess im easy on engines overall.

freeonthree

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If Brison recommends 100:1 for Gregs 50, why would it not be fine for my SV26 ? I trust Brisons judgment. Greg has never fouled a plug, or even had a deadstick landing with the 50 that im aware of, and we always fly together, so I would know. Also, I turned his engine while the plug was out last night, and it was as smooth as silk. From what i've seen so far, the 100:1 full synthetic is the only way to go, and I would never switch now, unless I have one of the problems you mentioned someday, and I seriously doubt that I ever will. The true test will be this summer when it's 100 plus degree's here. Greg runs 100:1 then too, and so far, no trouble whatsoever. Im gunna do the exact same with mine. We'll see....

freeonthree

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freeonthree, this is the part where you take a step back and listen to the members with experience. You don't just arbitrarily mix your synthetic oil at 100:1. You absolutely must mix the oil at the oil manufacturer's recommended mix.

Thats funny, at the field, Greg and I are considered the local experts. Tell ya what, you do it your way, and we'll do it Brisons way. As retired professional mechanics of over 30 years each, we see nothing wrong with Brison's reccomendations, and have evidence that it works just fine. Here, lets see what greg has been doing for over 4 years to his Brison onn a daily basis with 100:1, and only 100:1 since it was removed from the box it came in and bolted to the Pitts, then you decide. We sure aint switchin...
http://www.youtube.com/watch?v=BqOG4fRdyE8

torqmeister

Freeonthree, you obviously came on here to argue, or just to see if one of the experts would agree with what you are doing. It is too bad you didn't come on here to learn, and grow. In the short, and long term, the learning & growing would serve you well.
Best of luck to you in the future.

freeonthree

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OK, I guess my over 30 years of internal combustion experience means zip to you. I have been on RCU helping people for several years, im not new here. Your the one who likes to argue. I said the 100:1 is what Brison recomends for Gregs 50, and that it works great in my SV26, and you tell me im wrong, and that it will ruin my engine, yet it hasnt ruined Gregs engine, and he's been running it for over 4 years. I rest my case. Do what you want, im sure doing what I believe works the absolute best, and so does Brison. I've shared my opinions, and my proofs, so my job is done here anyway. have a nice day.

altavillan

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Wow! If you don't agree with one of the established experts yer stupid? And commited to be that way forever?

Jake Ruddy

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wow this turned interesting in a hurry.

Truth be told it's not going to matter what you run in that motor... it's not going to last half as long as a brison anyhow, the quality level between the 2 is night and day.

I really wish people would stop measuring engine time in years and switch to something useful like actual time running or gallons through an engine. To say an engine has been fine for 4 yrs doesn't mean much if it gets flown 4 or 5 times a weekend 3/4s of the year.

There has been lots of great info shared once again luckily it won't go to waste.


Personally I run Penzoil 50:1 and forget about it. If you have a bunch of slim at that then you are running rich (4 stroking). Do I need to clean it once inawhile? Sure maybe once or twice a month which for me means 32 - 50 15 min. flights. I don't find the cleaning too much of a chore myself.

freeonthree

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Nah, we fly at least 5 day a week, and some days we go twice, we've been doing it since 2002 when Greg taught me to fly. We are 2 sick puppies, but we know how to have fun. If were not flyin, he's at the drag races pounding on his 1000 HP Challenger R/T 426 Hemi on NOS, and im usually out ridin my homebuilt VW Trike between here and the coast. We have both been mechanics since we were kids, and were in our 50's now. I think we know what were talking about. lol

Jake Ruddy

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Well if the Brison gets used that much then it must have upwards of 50 gallons through it. Be interesting to see a picture of the piston Although I must admit I am more curious to see how long that SV lasts

pe reivers

Pat, if I read those pistons well, you also were experimenting with air-fuel ratio. The fact however that in the correct fuel/air ratio engine (picture 3) the ring also stuck tells the lean oil mix tale. My engines have a clean skirt, like fresh off the lathe.
The death ash I referred to, is on the other side (inside) of the piston crown, and indicated the piston temperature has been very near material collapse. That typically is the part not covered by the squish zone, which also has a large cooling influence.
Once the ring sticks, or has a large gap, gasses blow by and cause the piston to heat up rapidly as evident by the brown skirts. This will be aggravated by larger piston clearances.
I would love to have your job!

pe reivers

I'm a ships engineer by first profession. That means nothing. If I would treat my gas engines like ship's diesel engines, thos little buggers would be better off with somebody else.
A car mechanic knows some of the practical side of car engines (watercooled four strokes), that run at about 20% of their rated output. Our two stroke engines, air cooled and running 80+% of rated output most of the time, with dumb design cooling is quite a different story, and reading them is not quite the same.
Just checking the plug is only half the story. If the plug is of a cold type it may be even dry, non-sooty black at lean mixtures.
I will post a picture of plug readings for two strokes.

Plug 1 is slightly lean, as indicated by the head temperature.
plug 2 is slightly richer, the black ring still is not as high as 1/4 isolator length
plug 3 is too rich. The black has crept up to 1/3rd isolator length.
plug 4 is too rich, but heat range is OK (champion DJ7Y)
Plug 5 is too lean (no black ring) It also is too cold (champion DJ6J black nose)
plug 6 is right mixture as shown by mixture ring, but too cold.

And here is another plug, set up just right, dismantled for better vieuw

altavillan

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What difference does it make if your engine is running cool at 80% power verses 30% power. Seams that if you have it tuned and baffled to run cool at 80% power on 100 to 1 mix and occasionaly use 100% power you will be better off than tuned to run cool at 30% using 50 to 1 mix and occasionaly use 100% power.
Why is it so important convince Free he is a (fill in your own word here, mine was deleted) for using 100 to 1 mix. My prefered Syn oil company has been in business for over 30 years. I seriously doubt they would still be here if they didn't have a product that does what it claims.

Flyfalcons

Free is giving bad advice when he makes the blanket statement that synthetic oil should be mixed at 100:1 ratio. That's not how it works. You must use the oil manufacturer's recommended ratio. Do some synthetics recommend a 100:1 mix, yes! I run one of those and it works fine. However, you cannot take an oil designed to run at 50:1, 40:1, or some other mix and run it at 100:1 just bcause it is synthetic. That is just bad information.

altavillan

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Can't find that post anywhere. Are you refering to post #71?

blw

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Pe,

Great pics again.

RTK

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Altavillin--I feel the margin of safety (error) goes down with leaner oil mixtures, kinda proved it to my self in the past Ya better be sure mixtures are set correct and plenty of air flow directed the right way.

Tired Old Man

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The problem is in the retained heat stress that the engine endures.

The one running at 80 or more percent of it's output doesn't shed the heat like the engine that running at less of it's output or has a better controlled cooling source. Air cooling is extremely difficult to get correct for all engine output levels. It's easy to design for max heat, but when you aren't developing max heat the same cooling duct may work either too well or not at all.

Pe,

In truth there was no mixture experimentation taking place. The differences were obtained in the manner in which the engines were operated. The picture indicating a correct mixture simply was not run in the same manner as the other two. All were run for "extended" periods of time in similar atmospheric conditions. Fuel, oil, ratios, mixtures, and cooling methods were the same for all. Some of the piston crown bottoms did indeed reflect the high temperature conditions. Earlier tests performed at 70-1 ratios in a hotter enviornment had similar results. How they are run makes all the difference in the world. There are some other factors that influence the results but I'm not at liberty to elaborate on those.

In some ways you're right, my job is fun, challenging, and interesting but it has a caveat. When you're wrong a couple million $$ hits the dirt, so you try very hard to be right, or at least go great lengths to find out what is wrong.

OTH, I'd love to have your engineering background and education. There's some people at the office that would really hate me then

Flyfalcons

post 38 is where it starts

rmh

It may sound strange --but some of us simply listen to the engine instead of poking in the innards to se if all is well .
Of course , the plug/needle settings get attention when needed but a well setup ,properly lubed engine - just sounds "happy" all the time - it doesn't load down - it idles , flips easily - starts instantly etc..
Early on - I had problems deciding what sounded right .and found that when all was correct - the engine sounded best when
It produced max output with no slowing or loaded sound . (correct prop -best exhaust , proper cooling, setup etc., all figure in here.)

The co incidental part of this is that it all came together when I simply went to a 32-1 oil mix-
May have been only a coincidence but since then from new till--whenever the engines just became "happier" .
That's my story and Im stickin to it.

Tired Old Man

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I hear ya

freeonthree

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Im not telling anyone to run 100:1 so don't put words in my mouth please. OK, one more time, but this is it ! Greg has been doing just as his Brisons manual recomends, and thats full synthetic at 100:1. He's been runing it for over 4 years now, and his origional spark plug shows zero signs of any overheating whatsoever. Center insulator is a nice tan color, and the engine runs the same today as it did when he bought it, PERFECT !
For some reason you seem to think that im telling everyone to run 100:1, and that is simply not true, im merely stating my experience with 100:1 in my SV26, and Gregs experience of over 4 years with 100:1 full synthetic. You have to come to your own conclusions, and run what you feel is best, just as I have. The purpose of these forums is share our experiences, so that others can learn, consider, and decide, period. I am confused however as to how you can suggest that Brison Engine's is giving bad information in their manuals though. From what i've seen and experienced, I feel that Brison know's what their talking about. That's just my opinion, and if my engine ever tells me different, then and only then will I try something different. I trust Brison's recomendations, and will contine to do so until I see a negetive result.
Also, I have not seen a bottle of oil with mixing suggestions yet, just a chart, so that you can mix according to the engine manufacture's recomendations. Brison recomends full synthetic at 100:1, and the chart tells me to add 1.5 ounces per gallon. Thats what I did, and when I rubbed it between my fingers, it was obviously a much better lubricant than the 32:1 non synthetic oil mixture I tried in the first 1/2 tank which slimmed my plane, and I was not running rich at all, not even close to it. With the 100:1, I can set my mixture very rich, and the plane still stays oil free. These are just my findings, and I want everyone to have a great day, get some sticktime in, and have fun. If my engine blows up, I'll be the first to admit it, I got nothing to hide, and surely nothing to gain here. Just like you guys, im enjoying my RC hobby, and I continue to learn new things daily. Hey, I was shocked when Greg suggested that I use 100:1, but he talked me into trying it by puttin the Brison manual in front of me, and letting me read it for myself. I ran it for maybe 5 or 6 tanks so far, and I would never run anything else in my engine now. We all have to do what we feel is best for us, and im completely sold on the 100:1 full synthetic so far. Do what makes you happy...

Rcpilot

My Feedback: (78)

I think this is what Flyfalcons is referring too. It's misleading to newbies who may be reading this thread.

It doesn't matter one bit what the engine manufacturer tells you to run.

What MATTERS is what the mixing chart on the bottle of oil says.

If the mixing chart on the oil says it should be used at 50:1--then thats what you do. Just because the engine manufacturer says 100:1 doesn't mean you should do that.

Take that 50:1 oil and mix it at 100:1 because "thats what Brison says" and you just cooked an engine my friend.

You follow the directions on the oil bottle. NOT what the engine manual says. Engine manuals aren't the end all be all of what kind of oil or what ratio to run in the engine. It's a RECOMMENDATION and thats ALL it is.