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DL 50 low compressions, low power, bad idle

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DL 50 low compressions, low power, bad idle

Old 07-31-2009, 09:04 AM
  #51  
ArcticCatRider
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Default RE: DL 50 low compressions, low power, bad idle

Cambo,

It's worth checking out the ring end gap. If you've get a decent set of feeler gauges...check it out. What you do is remove the ring from the piston, and place it in the top of the cylinder...making sure the gap is in an area with no ports. (If it gets jammed in a port it might scuff or scratch something trying to remove it)

A rule of thumb for ring gap is .004 of an inch, for every inch of piston diameter. So, if you have a 2" piston, .008 of ring gap is your target.

Use the dome of the piston to push the ring down into the cylinder about 1/2 or 3/8 of an inch. Then, once your confident the ring is even and level in the cylinder, take the piston out and use your feeler gauge to check the gap. If it's too small...you can use some emery cloth to take some material off.

Use a magnifying glass to look over all your parts before you reassemble....check for any scuffs, burrs, etc., and deal with them before you put everything back together.

With as much carbon as you had in those pics, it's a good possibilty the ring was stuck...and your compression would suffer. It could have popped loose upon disassembly. In any event...too much carbon.

Lastly, if you have access to any measuring tools....take advantage. I would mic the piston in about 6 different places, and use a snap-guage or an inside mic, and check the bore. I'm not sure where you can find specs of clearances/tolerances...but something that's way outta whack would be obvious.
Old 07-31-2009, 09:16 AM
  #52  
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Default RE: DL 50 low compressions, low power, bad idle

Cold and too much oil. It was difficult to tell with the picture resolution, and if you don't have a macro function on the camera you can't obtain close up resolution, but the ring looked like it had not been seated yet. Cylinder condition indicated a similar condition.
Old 07-31-2009, 09:44 AM
  #53  
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Default RE: DL 50 low compressions, low power, bad idle

Why waste 20 gallons of fuel & time. Get a Frank Bowman Piston ring (about $10) and give it a try. His rings break in qutie fast. His phone 1-505-327-0696 or [email protected] Capt,n
Old 07-31-2009, 01:19 PM
  #54  
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Default RE: DL 50 low compressions, low power, bad idle

Captn,

I bought 12 of the Bowman rings to compare against two types of major maker OEM rings. With the engines I was involved with there was no benefit. Matter of fact, the Bowman's provided lower performance than what was obtained with either type if OEM rings.

I'm not making a statement that Bowman rings aren't worth the effort because in many cases they are. In this case, should they be run in the same way the originals were they would be in about the same condition. I can't see the benefit of a custom ring in this application, especially when stock rings are readily available.
Old 07-31-2009, 01:54 PM
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Default RE: DL 50 low compressions, low power, bad idle

WHICH WAY IS THE ARROW POINTING ON THE PISTON?

Towards the exhaust. Won't run if it's not.
Old 07-31-2009, 03:07 PM
  #56  
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Default RE: DL 50 low compressions, low power, bad idle


ORIGINAL: Tired Old Man

Captn,

I bought 12 of the Bowman rings to compare against two types of major maker OEM rings. With the engines I was involved with there was no benefit. Matter of fact, the Bowman's provided lower performance than what was obtained with either type if OEM rings.

I'm not making a statement that Bowman rings aren't worth the effort because in many cases they are. In this case, should they be run in the same way the originals were they would be in about the same condition. I can't see the benefit of a custom ring in this application, especially when stock rings are readily available.
I do not know if you set the end gap as Frank may have in your tests. He if I remember right, uses a very small end gap & he claims no rings have ever "stuck' or hurt anything from using a very small end gap. Maybe the end gap needs to be smaller. I just don,t know. What I do know every Bowman ring I have seen and helped install...worked super. Capt,n
Old 07-31-2009, 03:23 PM
  #57  
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Default RE: DL 50 low compressions, low power, bad idle

I work in an engine lab Capt'n, so I think we can presume all the possible factors have been accounted for. The "tools" available for measuring performance are unlimited. A well designed ring from any maker works super when set up correctly.
Old 07-31-2009, 03:52 PM
  #58  
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Default RE: DL 50 low compressions, low power, bad idle

Tired Old Man, I sure hope to be as nice and as wise as you are now! You know, even your old friend Ralph has been real nice lately. I sure miss the good old days in another time! Best regards capt,n
Old 07-31-2009, 05:43 PM
  #59  
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Default RE: DL 50 low compressions, low power, bad idle

Neither nice or necessarily wise. Unfortunately the older I've become the more developed a need to personally verify so many things. Happenstance has proven that many things i had taken for granted worked out about 60% as well as I had believed they had.
Old 07-31-2009, 05:53 PM
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Default RE: DL 50 low compressions, low power, bad idle

ORIGINAL: Tired Old Man

Neither nice or necessarily wise.
Are too!
Old 07-31-2009, 08:06 PM
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Default RE: DL 50 low compressions, low power, bad idle

All I can say is...AMSOIL DOMINATOR at 50:1. Mix at 40:1 for the first gallon and the 50:1 from there on. Another option for run-in ( I don't like the term "break-in" ) is a couple tanks of PENZOIL for Air Cooled engines at 32:1 and then switch to the Amsoil Dominator. I do not recommend the AMSOIL SABRE at 100:1. Especially with a fully cowled engine. To each his own but this stuff ( Amsoil Dominator @ 50:1 ) works for me. No carbon,no fouled plugs, just lots of flying. I have also found that the carb is easier to set and forget. Also no "burble" in the midrange. Just one mans suggestion. I also know these engines are low compression engines and are made to run on 87 octane but you can try "mid grade" gas and see what happens. Now the ZDZ's will take all the octane you can throw at them since they are a high compression engine. I run 87 or 89 octane in my DL-50 and 92 octane in my ZDZ's all with Amsoil Dominator at 50:1. I will also throw something else into the fire here.....cowled engines, like YAKs for example, present a difficult situation where the air pressure inside the cowl does not remain constant during flight. This is something to think about when encountering an erratic running engine. I hate it when everything is running great. That just means something will go wrong sooner or later!!! Speedy
Old 07-31-2009, 08:11 PM
  #62  
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Default RE: DL 50 low compressions, low power, bad idle

ive heard of the pressure problem before, and was wondering if that may be it. Ive asked someone about it before, and they said they wouldn't see how that would be a problem. I really don't have a clue though. My engine like i said was on a Cap 1st, rather closed up cowl, and now its on very wide open yak. The previous owner of this engine is the one who told me that it may be pressure.
Old 07-31-2009, 08:39 PM
  #63  
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Default RE: DL 50 low compressions, low power, bad idle

Real easy test. Make something up that looks like a small scoop and silicone it over the diaphragm hole. Face the open end of the ecoop to the back of the plane, or away from any wind blast. Do not block off the hole in the diaphragm cover with any silicone. If that improves things, make up a tube that runs from the diaphragm hole to the front of the carb venturi.

As for the Dominator at 50-1. Better take a another look at that 500 hour piston pic I posted. I have a lot of engines with that much time on them. The only way you'll ever see another one like it running the Amsoil will be in another picture. Yours won't live to see the day. No arguement, just try to get your engine to make it.
Old 07-31-2009, 09:50 PM
  #64  
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Default RE: DL 50 low compressions, low power, bad idle

As for the Dominator at 50-1. Better take a another look at that 500 hour piston pic I posted. I have a lot of engines with that much time on them. The only way you'll ever see another one like it running the Amsoil will be in another picture. Yours won't live to see the day. No arguement, just try to get your engine to make it.
??????

T.O.M., Please clarify. I don't understand what you are saying. I must admit that 500 hours is a lot of flying. You must have residence at your local flying field! LOL!

What oil are you using and what ratio? Maybe I will try your "brew"!

Speedy
Old 07-31-2009, 10:17 PM
  #65  
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Default RE: DL 50 low compressions, low power, bad idle

That wasn't out of a sport plane... Go with Valley View's suggestions.
Old 07-31-2009, 10:25 PM
  #66  
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Default RE: DL 50 low compressions, low power, bad idle

You are running REDLINE racing oil? I've looked at a bottle of it at the local bike shop and the owner highly recommended it. If this is what you are running what is your mix ratio? As per instructions? I've heard that if all else fails you should read the instructions!! I am simply amazed at the picture you posted of the 500 hour piston. It is much easier to ask you directly than to look up Valley View's past posts. Speedy
Old 07-31-2009, 11:03 PM
  #67  
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Default RE: DL 50 low compressions, low power, bad idle

Hello to all...

I've been reading this forum with great interest. I have a DL50 engine... It has about seven gallons of fuel through it - first four on Penzoil air cooled at 32:1, the rest on Red-Line synthetic two cycle racing oil at 40:1. It starts easy, has plenty of power, idles and transitions great. Just recently though I've noticed that in the mid range it started to "hunt" some what. What I mean by hunting is that rpm varies up and down on its own, with out throttle input.... I've tried adjusting the needles, but cannot seem to be able to correct that. Any suggestions ????

Paul.
Old 08-01-2009, 09:08 AM
  #68  
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Default RE: DL 50 low compressions, low power, bad idle

T.O.M. I think we have crossed paths in other forums and your knowledge and advise is always right on the mark! I contacted Valley View RC and he gave me the info.

jedijody ( Valley View RC ) your PM is greatly appreciated. As I stated before, I am having good luck with the Amsoil Dominator but am always open to trying new things including engine lube for gassers. I will give your suggestion a try. You may make a believer out of me!

Thanks to both you guys! Good is good but who's to say something else is not better!!!

Speedy
Old 08-01-2009, 11:36 AM
  #69  
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Default RE: DL 50 low compressions, low power, bad idle

The instructions I got with the Bowman rings for the DL50 says the gap should be .002 to .003. If greater than that, to contact Frank, and he would send out another ring.

Greg
Old 08-01-2009, 02:12 PM
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Default RE: DL 50 low compressions, low power, bad idle

xman2004:
There has been a lot of discussion on the presence of ETHANOL in many gasolines and the effects of deterioration to the seals and diaphrams of carbs on small engines. Something to consider when buying gas and when diagnosing engine problems.

T.O.M./jedijody:
Just bought some Stihl HP Ultra and will use at 50:1 for a while. The plug and exhaust port should tell all after a few gallons. May take some needle tweaking but that is expected when changing from one lube to another. The good thing is that my engines are clean to begin testing so any change will be attributed to the new oil.

There is a lot of B/S in these forums but I can tell you guys know your stuff. Everyone must understand that there are many products out there and no single product works exactly the same for all engines or applications. Getting good information is a great starting place but the results are unique as per each individual. It is absolutely wrong to suggest to someone that the product they are using is bad or good. That decision must be determined by the user and their knowledge of how to properly run, adjust, and maintain a model engine.

A 2-stroke glow engine would seem quite straight forward to run right? NOT TRUE! Enter the competition racing arena and you will find many variables that make drastic changes in how the engine runs. The same is true with "Gassers". One of the biggest things to remember is:

"A CLEAN RUNNING ENGINE IS A GOOD RUNNING ENGINE!"

Maybe that is why my wife insists that I take a bath! Let's see now......which soap should I use?

Thanks again! Speedy
Old 08-01-2009, 06:51 PM
  #71  
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Default RE: DL 50 low compressions, low power, bad idle

There are two oils that I use, both at 50-1. Redline an Stihl HP Ultra. Motul 800 and Royal Purple are a couple others that are very high up the list. Pennzoil is real good but I just don't like the amount that's required to do the best job.

Some of my engines run pretty hard and for that reason a few others, Amsoil will never see the inside of one of my engines again. Lawnboy will never get in my shop, let alone and engine. A gentleman that does serious engine time on the east coast, RC Bugman, had the same experiences I did with their products.
Old 08-01-2009, 07:51 PM
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Default RE: DL 50 low compressions, low power, bad idle

Tired Old Man,

I also use Redline oil, but at 40:1 mix ratio with very good results... I run this oil in all my engines which include DA, Evolution, Brison, DL, and ZDZ... I was thinking about going to 50:1 ratio for a while but since DA and and Evolution both recommend it at 40:1 I stuck with it. How ever I see more people lately who seem to run it at 50:1, partly because they believe that 40:1 is just too much oil....Do you think 40:1 is too heavy on the oil, and perhaps I should change to 50:1? And, for the engines which manufacturers recommend 40:1 is it safe to go to 50:1?

Regards,
Paul.
Old 08-01-2009, 09:02 PM
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Default RE: DL 50 low compressions, low power, bad idle

Redlide is fine at 40 or 50-1. About 8 years ago I was running it at 70 and 80-1 until I learned better. For the inevitable question, the Stihl HP Ultra is a better oil, but the gain is found in the upper heat ranges. I try not to run my personal engines in that area so the Redline is great for me.

Only the owner knows how they run an engine. Hot, lean, poor air flow, heavy prop load? More oil and the best you can get is the key there. Reasonable mixture, good airflw, aveage prop loading, lower temps? Then most oils work fine from 32 to 50-1. Some work better than others but the effects won't be noted for a very long time. As I've ssid before, most will hit the dirt long before the oil made a difference. There are those engines where oil will have an impact from the beginning. Usually negatively. They will start an irreversable process.
Old 08-03-2009, 08:59 PM
  #74  
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Default RE: DL 50 low compressions, low power, bad idle

So Jody got the cylinder, piston, and ring today. I talked to him for about 20 minutes. The answer is honestly what i expected. I am going to be purchasing a new cylinder, piston, and ring. It sounded pretty bad from his description.
Thanks for all the help all
Cameron
Old 08-03-2009, 09:31 PM
  #75  
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Default RE: DL 50 low compressions, low power, bad idle

I have a macro function on my camera, I'll try to post some pictures later.

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