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Dle-20 Blew up....

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Old 02-07-2011, 02:58 AM
  #76
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Default RE: Dle-20 Blew up....

To all that responded, thank you! I did not consider the alcohol when using regular versus premium. It makes sense.
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Old 02-07-2011, 06:12 AM
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Quote:
ORIGINAL: Tired Old Man

Truckracer,

I work a fuel where adjusting the needles will not compensate for the difference in energy content. This fuel is a broad spectrum fuel that encompasses a wide range of cetane ratings. If one starts out with a well tuned engine using a higher cetane rating then switches to a lower quality/cetane rating they will not be able to compensate for the difference at the carb needles. The best one can hope for is a considerable loss of RPM while delaying knock, and increased fuel consumption. This applies to carbureted engines only.
With all due respect TOM, I really don't care about your research .... in this case. This thread is dealing with a DLE20 and I would assume the common fuels that engine might be burning when the engine is used in a typical model airplane...... not an exotic RPV. In this case, yes, a simple turn of the needle valve will compensate for the differences between any of the commonly accepted and used fuels for these engines.
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Old 02-07-2011, 06:18 AM
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Default RE: Dle-20 Blew up....


Quote:
ORIGINAL: a1pcfixer


Quote:
ORIGINAL: Truckracer

A simple twist of the HS needle valve offsets any differences in the energy content of the fuels used..................
Unfortunately, not all types of engines allow the range of adjustment to do so.

I miss adjusting Holley carbs. Swapping out jets on those was somewhat of an art form.
Doing the same on a GM Quadrajunk was a science unto itself......and a nightmare.
I can't think of a fuel that would commonly be used for a DLE20 that can't be compensated for by adjusting the needles on that engine. This is a DLE20 thread, not a Holly carb tech clinic. The difference between a straight gasoline mix and a 10 to 15% ethanol mix is about 1/8 turn on the HS needle.
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Old 02-07-2011, 07:41 AM
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Default RE: Dle-20 Blew up....


[Never mind if I'd read the whole thread prior to posting my question about which brand of oil to use I would have never posted.

Dave
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Old 02-07-2011, 08:15 AM
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Default RE: Dle-20 Blew up....


Quote:
ORIGINAL: w8ye

28 degrees BTDC is where most engine are set

I just examined my DLE 20 and I don't see any timing marks. So how do I determine it the timing is set at 28BTDC?

Dave
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Old 02-07-2011, 08:23 AM
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Default RE: Dle-20 Blew up....

Here is a good video on setting the timing..

http://www.youtube.com/watch?v=GBXFpxWg7vY
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Old 02-07-2011, 08:29 AM
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Default RE: Dle-20 Blew up....

Quote:
ORIGINAL: a1pcfixer


Quote:
ORIGINAL: Truckracer

A simple twist of the HS needle valve offsets any differences in the energy content of the fuels used..................
Unfortunately, not all types of engines allow the range of adjustment to do so.

I miss adjusting Holley carbs. Swapping out jets on those was somewhat of an art form.
Doing the same on a GM Quadrajunk was a science unto itself......and a nightmare.
This is where benefits of the Walbro WY series carbs are obtained. The metering needle (singular) has the most impact on the low end while significant changes in the top end require changing jets. There are a great many jets available for experimentation, along with metering springs. Once you learn how to use one, WY carbs make for a smoother running engine. And you don't need to buy some half baked Chinese iridium plug to enjoy the benefits. For those that have a head for experimentation, WYL carbs were orignally developed for use in the 35CC and under class of gassers.

BTW, the difference between a 10% methanol blended gas and straight gas is roughly a 3% leaning of the mixture. Truckracer is correct that anyone should be able to tweak the needles to balance out the difference, provided the carb is sized correctly to the engine. I am not being specific to the DLE 20 because the condition is relative to any of the engines we use, in any size.

Leaving RPV stuff aside, ambient and operational conditions impact which fuel may or may not work best with an engine. Vapor pressures come into play, but that is well beyond where anyone in this thread really needs to go. It should be sufficient to say that people should purchase name brand fuel and take a moment or three to tune their engines. The ones that will have th emost trouble will be the people that think engines are ready to fly out of the box.
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Old 02-07-2011, 08:40 AM
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Default RE: Dle-20 Blew up....


Quote:
ORIGINAL: Truckracer

This is a DLE20 thread, not a Holly carb tech clinic.
Actually even that is off the mark.
This thread is about a DLE20 that blew up, not adjusting the HS needle.

The DLE20cc gas eng thread is over here......
http://www.rcuniverse.com/forum/m_98..._1/key_/tm.htm
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Old 02-07-2011, 08:49 AM
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Default RE: Dle-20 Blew up....


Quote:
ORIGINAL: a1pcfixer


Quote:
ORIGINAL: Truckracer

This is a DLE20 thread, not a Holly carb tech clinic.
Actually even that is off the mark.
This thread is about a DLE20 that blew up, not adjusting the HS needle.

The DLE20cc gas eng thread is over here......
http://www.rcuniverse.com/forum/m_98..._1/key_/tm.htm
Point well stated there a1! I think they call it thread drift. [8D]
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Old 02-07-2011, 01:32 PM
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Default RE: Dle-20 Blew up....

My point in here was about the guy using 100LL and how it is a waste on this engine. 100LL and "race" gas burning at a slower rate than pump gas. I just thought it was funny because in my quad days riding in the dunes many guys would have a bone stock or near stock engine and run "race" gas thinking their bikes where faster, smelled better, and ran better lol. even running 91-92 gas in a bike that can run on 87 isnt as good.

Also guys that find the first thing they find on the net and post it. There is so much misinformation out there. I admit i am no expert either but have done some much reading on engines that have learned a lot.

If you want to run 100LL or even "race" gas then go ahead you can do what you want. i will run regular 87-89 in my stuff just like the MFG says to. If i need more power then buy a bigger engine.....
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Old 02-07-2011, 05:28 PM
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Default RE: Dle-20 Blew up....



You don't need higher head temp(but will create)for major detonation, but with major detonation would be excessive power loss which would be unmistakenably obvious.

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Old 02-07-2011, 08:03 PM
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Default RE: Dle-20 Blew up....

WOW, thought i would read about a dle20 issue or operator error and i get a discertation in inorganic chemistry,,,,whew
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Old 02-07-2011, 10:11 PM
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Default RE: Dle-20 Blew up....

Parts are in and the engine is back together test soon to come.
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Old 02-07-2011, 10:29 PM
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Default RE: Dle-20 Blew up....

Back to the original issue then. Synopsis: The crank broke, ordered another one, going to fix it. Possibly caused by a prop strike not mentioned in the opening thread. Prop strikes can do that too.

Pretty much end of story as far as the original topic is concerned. What else is there to talk about regarding the crank?
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Old 02-08-2011, 05:56 AM
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Default RE: Dle-20 Blew up....

TOM I would some what agree with your statement about people having the most problem are the one's expecting it to run right out of the box, But I've seen the group that has the most trouble with their engines are the tinkers, They are always tuning their engines.
Some years ago when I had quadras, A and M sachs, and Zenoahs after my intial tune I never touched those needles and flew those engines for years
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Old 02-08-2011, 06:38 AM
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Default RE: Dle-20 Blew up....

Good point. Once set there's generally no further need to mess with them for a long time on until changing props. There's probably a lot of recent glow converts that might be under the impression you have to tweak the needles every time they go out.
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Old 02-08-2011, 06:46 AM
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Default RE: Dle-20 Blew up....


Quote:
ORIGINAL: captinjohn


Quote:
ORIGINAL: Tired Old Man

Lead is the problem, not carbon. I dare anyone to try cleaning tetra ethyl lead out of a two stroke bearing. Been there, couldn't do it. The plugs were hard enough.
I am learning...what does the tetra ethyl lead to do the 2 cycle bearings? Is it both the ball type or the needle or roller type of bearings that are effected? Thanks Capt,n
TOM, unless I missed it...what about this lead...bering problem...still wondering!
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Old 11-09-2012, 08:01 AM
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Default RE: Dle-20 Blew up....

Another DLE 20 hits the dust. After 5 gallons the crank pin broke and damaged the crankcase. This is my friends motor not mine. It happened after startup and run at full throttle back to idle and then back to full throttle on the ground first run of the day. Yes I was there and saw it happen.
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Old 11-09-2012, 08:53 AM
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Default RE: Dle-20 Blew up....

What's your point? That it's possible to blow a DLE 20?
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Old 11-09-2012, 02:32 PM
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Default RE: Dle-20 Blew up....

No point, just wondering if others are having this happen after a few gallons. I happen to have several DLE engines, but just started using the 20cc, mine has 1 gallon through it.
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Old 11-09-2012, 05:32 PM
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Default RE: Dle-20 Blew up....

The bigger problem that I know of is when over revved, as in too small a prop is (was) used. Otherwise, there's been no rush of guys writing in with that experience that I'm aware of. I don't know how much fuel mine's had through it, but it's been run hard in a 20cc profile teaching me to 3D for the last couple seasons now. Pretty rough service and it hasn't missed a beat!

Did the engine come from Tower, maybe still under their 2 year warranty?
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Old 11-09-2012, 05:35 PM
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Default RE: Dle-20 Blew up....

I suspect the problem lies in improper heat treatment by the manufacturer, or to be more specific, improper "nesting" of the crank shafts in the heat treat furnace. Most of the parts come out within spec, while a few others end up with inferior metalergy......It's a crap shoot, some are bad, most are good.
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Old 11-09-2012, 07:16 PM
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Default RE: Dle-20 Blew up....


Quote:
ORIGINAL: Tired Old Man

My "thoughts" about the use of avgas in our engines has remained unchanged for years. Don't do it. The stuff is also called 100LL. LL stands for low lead. "Low" is used as a comparative term. The lead content is low compared to the amount of lead auto gas had before unleaded fuels were incorporated. That was back in the 1980's. Engines that used leaded gas had things like valves and valve seats, and the metal chemistries used in engines was different then. Sealed bearings weren't used in areas that would collect residual lead.

Our little engines do not meet any of the qualifications that require leaded fuels. Our spark plugs load up with lead after a period of time, especially in engines that will run for long periods of time. Residual lead becomes trapped at wrist pin and rod bearings. Some is forced inside of sealed bearings.

If someone really believes they need 100 octane fuel for an engine that was designed for octanes between 70 and 90, then recing fuel with no lead is available. Eventually they'll figure out their low compression engine doesn't have the power his buddy's engine does. The reason is because his buddy is using pump grade regular unleaded and all the fuel is being burned during the combustion cycle, while his engine is not using the full charge because the high octane is maintaining a slower burn. His buddy is also getting his gas for $2.00 a gallon less than he is, and can buy it on any street corner.

But what the heck, some people figure, wrongfully, that more octane equals more power. Others figure that because a fuel is intended for a real airplane that it must be better than our pump gas. That's not the way things work.
A better fuel yet is a gas that is pure gas with no additives. Stations that sell it can be found online or near places where a lot of boating is taking place. It is not much more in costthan regular gas but really works good in 2 stroke & small 4 stroke engines. I talked to the dealer when I bought some and he said more & more people are buying it for lawn equipment engines like 2 cyle engines. Boat owners & Motorcycle owners buy it too. My engines really run good using it.

Capt,n
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Old 11-09-2012, 07:27 PM
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Default RE: Dle-20 Blew up....


Quote:
ORIGINAL: SkyPilot101

I suspect the problem lies in improper heat treatment by the manufacturer, or to be more specific, improper ''nesting'' of the crank shafts in the heat treat furnace. Most of the parts come out within spec, while a few others end up with inferior metalergy......It's a crap shoot, some are bad, most are good.
The 20 uses a pressed in crank pin so the crankshaft as a whole is not the problem. I would remind those quick to point fingers that DA had a similar problem with their ever so famous DA50 a few years back. They replaced the bad parts and that problem is now gone as far as I know.
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Old 11-09-2012, 11:31 PM
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[Hello everyone,i am a newer to here,i am form china,Hope i can learn and share something about DLE Products here.......
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