WacoNut

Gotcha,
It does sound like the oil caused you an issue. Can't hurt to try something different.

azalner

My Feedback: (8)

The Bowman rings will seat much faster than the OEM rings. I have three DLE-30s (rear carb) with Bowman rings installed from day one. Been running them for the last three flying seasons and they just keep getting stronger. Two flips with choke on to prime, ignition on, choke off and they start on the first flip. Stihl Ultra synthetic, 32:1, 100LL avgas. 7400 rpm with Xoar 19 x 6.

Lifer

My Feedback: (1)

Plus 1 on the Bowman ring. I have one in a DLE 55 and it's the best running engine I own.

kerwin50

Somebody lied to you. Don't use the ashless oil. Sthil Ultra all the way and you will not have any carbon build up nor a fouled plug

j_keiter

My Feedback: (21)

New issue tonight. Engine would lean out when inverted. I had set the hall sensor bracket back to center the last time I put everything back together. Since I was having lean out issues I thought I should check the carb diaphram and while I was at it I checked the timing one more time. This time I took much more care to be as precise as possible. It appears the center of the hall sensor bracket set the timing at 35 deg. I moved it counter clockwise/same direction as prop till I got 30 deg. Flew it and no more lean inverted dead sticks. There is still some lean out when inverted but it never died on me as it did before. I also was able to lean the low needle a little bit to smooth out the upright flying. This engine is mounted inverted on a 30cc Yak 54 so when when I fly inverted the engine is upright but the fuel tank sits lower than cylinder but not carb?? Carb seems pretty centered compared to fuel tank?? Someone prior to this post mentioned 40 deg. Starting to wonder if different dle's have slightly different hole positions for the hall sensors? I'm flying Hi G Imac patterns. I did try .020 and .025 on the NGK plug. Did not seem to make a difference. Timing made a big difference. Getting 6800 19x8 and 1800 idle.

j_keiter

My Feedback: (21)

Man, I just cannot win with this engine. This was from the manual that I think valleyview created. It appears the 35 degrees is supposed to be correct for the dle 30. Mine seems to run and idle better at 30 deg. I also noticed some kick back when it was at 35 deg. It was still easy to start at 30 deg.

Ever since the rear carb DLE30 was introduced, the ignition

module has been made with a unique timing curve that retards the timing further than the standard Rcexl ignition for a slower and smoother idle. The correct factory set timing is 35-36

BTDC;there is a 6-8 degree adjustment in the slots of the sensor. The DLE30 will run with the timing set to 28-30 but it will be harder to start. The engine runs best when timed at 35-36
BTDC and it's almost always right on out of the box.

kerwin50

I would of sent it back under warranty. My DLE 30 never seems to miss a lick. starts great idles perfect and just screams. Inveted, high G's. what ever I can throw at her. My Timing is set at 28 degrees.

kerwin50

Here's a video
http://www.youtube.com/watch?v=4neuVcCXHPg

chuckk2

The evident shift in timing is a bit worry-some.
We had this kind of trouble with some of the early automotive CD ignitions. Turned out that
voltage spikes were damaging some of the components. The spikes were higher in amplitude
than the engineers had accounted for in the designs. Even the amount of shift (~10) matches.

j_keiter

My Feedback: (21)

For all interested. Here is a video of my DLE with timing at 30 degree. I ramble on a bit. Sorry about that.

http://www.youtube.com/watch?v=9Pn_E...ature=youtu.be

azalner

My Feedback: (8)

Something doesn't sound right about your timing numbers. I have three DLE-30's and they are all timed spot on at 28 degrees BTDC. What method are you using to check the timing? I use Ralph (Antique) Cunningham's method. It's easier, faster and in my opinion more accurate. See this link:

http://www.phprc.net/images/engine-timing.pdf

Perhaps you can post a vid of your timing procedure. BTW all DLE ignitions are made by RCXel.

j_keiter

My Feedback: (21)

Both towerhobbies listed manual and the manual on the dle website lists 46 deg before top dead center for timing. I found this DLE 30 manual online that listed 35 deg btdc. http://images.rcuniverse.com/forum/u...26/Tr50265.pdf
I used a degree wheel to maximize my resolution in reading the numbers. I pulled the carb and reeds to see the crank pin and hold at tdc to engrave a mark on the prop hub to indicate tdc. I now align degree wheel 0 deg when prop hub engraved mark is lined up with the web on the casting for tdc. I use a popsicle stick and small clamp to make dial indicator for degree wheel. Popsicle stick is clamped to the webbing of the engine case. I now gently rotate the hub and only listen for spark in direction that prop moves (counter clock wise). As I said before I consistently measured 35 deg with the sensor bracket at center of it's adjust range. 35 deg coincides with the dle30 manual that I fount online on RCU. I like this manual. Especially as the manual from dle indicates a 46 deg btdc timing which I do not understand??? I also usually do a sanity check by holding an allen wrench up through the spark plug hole against top of piston and toggle around tdc to make sure my marks make sense. I like Ralph (Antique) Cunningham's method but feel I get better resolution with a timing wheel. Please respond if you see a mistake in me method. Thx Jason

Truckracer

My Feedback: (19)

About the only thing I would do different would be to use a positive stop on the piston to locate TDC. This is usually an old plug with the ceramic removed and a piece of metal is soldered where the elements were. I grind a slot through the threads to let air escape as the engine is rotated and so there is no compression feel. The metal stop should stop the piston rotation about 10 to 30 degrees before TDC but this number is not critical. Rotate the engine one way by hand and firmly against the stop and note the location on the degree wheel. Rotate the other direction and likewise not the location on the wheel. The distance half way between the marks is TDC and you won't find a more accurate way to locate TDC. This method removes any bearing tolerance stackup as the bearings are under equal compression when you take the location readings. No human can exactly locate TDC visually without proper tools and even using a dial indicator on the piston doesn't correct for bearing slop.

With all that said, exact timing is not at all critical. Anywhere from 26 to 30 degrees should work with very little difference in performance. Certain engines might be more critical than others. Too much timing is worse than too little. Too much timing can cause rough running, missing, overheating and a needle that just doesn't want to take a set. Within a few degrees, too little timing will usually just cause a drop in top end RPM and acceleration (mid range torque). Long before timing was set by degree wheels, etc. it was set by ear and the method usually worked quite well. We just increased timing a bit at a time until RPMs stopped increasing and rough running was noted. From there it was backed off a bit and the engine was good to go. In my opinion, people make way too much of this timing issue, especially when they start splitting hairs with exact timing numbers.

kerwin50

28 degrees is the reccomened timing. Also be carful tightening the carb/reed block down. It can distort the reed block.

Whiskey Bravo

My Feedback: (31)

+1

azalner

My Feedback: (8)

Not true, they both indicate 35deg BTDC is the correct number, the 46 deg figure is what you would read if you rotate the engine clockwise.

It seems to me that I read somewhere that RCExl is making special ignitions for DLE that have a different advance curve (smoother), but this shouldn't affect where to set the initial timing. The timing setting should only affect ease of starting. The timing will advance as the RPM comes up. I use 28 deg and my engines start on the first flip after priming. They will idle all day at 1500 RPM but I prefer to keep my idle speed around 1750 RPM.

j_keiter

My Feedback: (21)

Thank you azalner for clearing up the strange 46 deg figure on the dle manual. Would of been nice of them to indicate they were timing in the clock wise direction. I reread the timing section and no mention of which way to turn the prop for timing. Not sure why they measure it that way in the first place? The prop spins counter clockwise?? Bizarre! I agree with you exactly on timing and idle speed of 1750.

av8tor1977

My Feedback: (6)

This is absolutely correct. We had a heck of an argument about this a couple of years ago here in the forums, but what you state is the only true, proper way to determine TDC. You just forgot to mention that it not only allows for bearing clearances, but also for the piston dwell time. The piston dwell is the time the piston sits motionless at TDC while the crank is going across its arc and getting ready to pull the piston in the reverse direction, (downward). There are several degrees of crankshaft rotation while the piston sits motionless at TDC. I just got through hopping up a Homelite 25cc engine, and there was about 8 degrees of crankshaft movement at TDC with NO movement of the piston. The degree amount of piston dwell will vary from engine to engine depending on the rod/stroke ratio, rod length, etc.

Trying to use a dial indicator or a stick to find TDC allows for large errors in timing, whether it be port timing you are working with, or ignition timing. A dial indicator CAN be used to get pretty close to TDC if you use it to measure a fixed distance down on either side of TDC instead of just using it to determine when the piston is at the top. It is not as accurate as the Positive Stop method however, because it does not account for bearing clearances.

To make my positive stop, I gut an old spark plug, cut off the ground electrode, then epoxy or JB Weld a piece of tubing into the center, sticking down below the threads of the plug a bit. The tube stops the piston, while being hollow allows air to escape (or enter) when I am turning the engine over.

AV8TOR

Whiskey Bravo

My Feedback: (31)

I have used all the methods alluded to in this thread and others and have found that the most accurate is a positive piston stop as mentioned by Truckracer and av8tor1977. I have two new DLE 20RAs I plan to install in an F7F tigercat this winter and checked the stock timing on both with 35 deg. as the results. I moved the sensor on them in an attempt to get near 30 deg and while one was easily adjusted to 30 on the other I would have to grind away some material on the plastic that houses the sensor to get to 30. Not really a problem to do so however it seems odd there is that much difference in the two. I ended up setting them both at 32 deg and should be ok.

j_keiter

My Feedback: (21)

What a coincidence. I just measured my side exhaust dle 20 timing this morning with sensor bracket at center I got 30 deg timing. Since the rear exhaust is newer model I wonder if dle is going to stick with the 35 deg timing for all future engines? I prefer 30 or less. Did have some lean out dead sticks while flying inverted on my Yak with side exhaust dle 30cc at 35 deg timing. Moved timing from 35 to 30 and still noticed lean when inverted but never died. I've got another hour of time flying Imac and no more dead sticks with timing at 30. I can only guess the 35 ran just a llittle hotter such that it died when leaned. This is all speculation of course. Be nice if carb would not change mixture due to G-force but that is another issue. I have run diaphragm pressure tube into fuse. It's not a change in pressure issue. I'm leaning towards g-force acting on fuel regulator diaphragm. Only way to know is if someone mounted the dle sideways instead of the inverted config I have. Sideways would leave the diaphragm running parallel to the G-forces. Anybody?

Truckracer

My Feedback: (19)

Av8tor, thanks for the vote of confidence regarding the positive stop. Yes, I completely forgot to mention piston dwell and as you mentioned, it can be quite a few degrees and it only increases as an engine ages and bearings get more free play. Commercial positive stops are available for nearly every size sparkplug and of course for engines with removable heads such as automotive applications.

I chuckle a bit when I hear someone say their timing is adjusted to exactly xx degrees then they quite a method for finding that number that had multiple posibilities for error. Still probably good enough for our simple engines.

Truckracer

My Feedback: (19)

If G forces are causing your problem, increasing the pop off pressure in the carb can help that issue. Do that by either slightly stretching the spring under the forked lever in the carb or stronger springs are available from Walbro. This usually only helps if the pop off pressure was too low or marginal to begin with.

av8tor1977

My Feedback: (6)

I think the only way someone could verify that the ignition models in question are designed for the timing to be set at 30, or instead 35 degrees, would be to make some timing marks on the engine, and check the timing with a timing light with the engine running at various rpms. What we want is 28 to 30 degrees timing at max rpms. The units that are designed for 35 degree initial timing settings probably just retard more at starting and idle rpms, but end up with the same max rpm advance as the other ignition units, ie. 28 to 30. Retarding the timing on an ignition unit designed for a higher timing setting would cost power.

It would be nice if someone could talk to RCEXL and/or DLE and find out the real scoop. (Wish Jody was still around; he'd get it straight for us!)

AV8TOR

j_keiter

My Feedback: (21)

Pulled spring from dle30 carb diaphragm check valve regulator assembly. Measured 9.5mm long. Stretched to 12.5mm long. Flew and no difference. Positive G loops go rich at bottom of loop. Negative G loops run smooth all the way through. I repeated over and over to confirm. If I get time I'll try to find a walbro spring to compare. The dle spring was extremely light, but I had nothing to compare. It's flyable like this but annoying. av8tor1977 you are looking at the timing the way I did. Apparently 2-strokes actually retard timing at a certain point during the increase in rpm unlike 4-strokes that simply advance timing as rpm increases. I'm confused why we set timing at 30 deg static. That would infer that the engine runs with 30 degree timing or close to it at low rpm/idle. I looked at some timing curves for 2-stroke motorcycle engines etc on the web and they show a hump type curve as rpm starts from 0 to max. Initially they would advance till around 3-4000rpm then they would retard. Explanation got complicated and I gave up at that point. I'm curious if our plane engines are just crude enough that they get by with a straight timing curve/line. I would love to see a graph of the timing versus rpm for my dle 30.

Truckracer

My Feedback: (19)

When the magnet passes the hall sensor at low speeds such as when checking timing, the ignition is at full advance. Actually "not retarded" would be more correct as our ignitions retard the ignition when running at low speeds then go to full advance or the timing set during a timing check at or after a pre-determined RPM. The advance (again less retarded or not retarded with speed) could happen very quickly or over an RPM range depending on the program in the ignition. Further, the ignitions go to full retard when the prop is flipped briskly for starting or when the engine is running slowly. Confused?

Stated a different way, our ignitions retard the spark at low or cranking speeds from the pre-determined amount of timing set during a timing check. Our ignitions do not advance timing they only vary the amount of retard based on engine RPM and the program set into the ignition box. There may be some out there but I know of no RC EI boxes that can advance the timing beyond what is set during static timing set.

I have no clue why DLE sets their engines with so much static timing. There are many threads that describe resetting timing to the more reasonable numbers that have become common for our engines and applications. It would be interesting to hear from someone at DLE to know their reasoning. It would be especially interesting to know their reasoning behind the horrible #4 ignition that causes so many problems for DLE20 owners.