JoeyCoates

Ok, I have a brand new DLE35ra that I have bench run maybe 12-14 Oz through while mounted on the airplane. The gas is mixed 30:1 per manual with husqvarna oil. Basically I was just running it to set the needles and check transition. Now to be perfectly honest this is my first larger gas engine, my only other gas engine is a Evolution 10gx so I am very new to this. Before the engine ever ran I put a Bowman ring on it and made sure the reed block was flat. I then made sure the high and low needles were at 1.5 turns for low and 2 turns for high, they were way off out of the box. I also put in a nkg plug gapped to a #11 exacto blade, very scientific I know but it ended up with about a .023 gap. I also set the timing to 29 degree's from the 35 that it shipped at.

As I said, I put a Bowman ring on it before it ever ran. The stock ring gap is .012 whereas the Bowman ring has a .005 gap, so far so good. The Bowman ring went in with no issues, this is my first larger gas engine but I have flow glow for over 30 years and have built a lot of other engines. Before I ever started the engine the compression felt a bit soft compared to what I am used to, but it had never been ran so I did not think anything of it.


I started and ran the engine this evening. Once it popped with the choke on it only took 3-4 flips until it started right up, good to go. So I gently ran it up and down a bit with a Xoar 19x8 beechwood prop. It would only hit about 6400 rpm's as it was a bit rich. I leaned it out to hit about 6800 rpm's (only held peak for 5-7 seconds) and then would work it up and down rpm's for about 5 minutes. It holds a 1600 rpm idle easily. I shut it down and let it cool before I ran it again. When I ran it about 15 minutes later I followed the gas tuning procedure in the sticky at the top of this page. Again it started very easily, not much compression though, and I let it warm up. I then starting tuning the high end a bit at a time, I could not get a screwdriver on it at full rpm's due to vibrations so I would lean it a bit, go full throttle and look at rpm's, and then lean it a bit more. Once I got to about 1.2 turns on the high end an 7200 rpm's I did not lean it any more as I was worried about overdoing it. I backed the high end out about a blade width settling a little over 7000 and tuned the low end like the sticky said to. It runs clean and transitions well, but even when green should it have more rpm's? I keep reading where gas engines should be tuned to close to peak rpm's from the very beginning and that they do not pick up much from breaking in.


I shut the engine down after about 5-7 minutes tuning and i could turn it over with one finger very easily. I turned ignition back on, flipped it, and it started right up holding a 1600 rpm idle. I then shut it back down. The compression was very low while hot which is not necessarily abnormal, but it was really low. Once I got everything back inside I pulled the engine off to look through the exhaust port, everything looked good. I pulled the cylinder to make sure nothing was scored but it looked great. The ring has a few places where it is getting a little shine (seating) but mainly black. Just to see I put the stock ring back on and bolted cylinder down, a lot more compression even with the larger gap, it would actually "flip" with very little effort. Took it back off and put Bowman back on, much lower compression and I really have to put some speed on it to get it to flip.


So, will it start to seal with time? I know some people like to break in on bench, some in the air. I was just going to run it to set needles and then fly. At 7200 rpm's it will certainly fly, but I have read where people are getting a lot more rpm's with a 19x8 Xoar. If it were a glow engine I would not be too worried as they do tend to pick up, but I keep reading where gas is different. I might be able to lean the high end more, but I was by myself and it was too difficult to try and tune the top end more with it running. I will get one of the gas guys to help me once at the field, I am more concerned with the lack of compression. Even when cold I can turn it over with one finger pretty easily. And I am not trying to say anything negative at all about the Bowman ring, too many people have had great results with them, I just do not know what I am doing wrong right now. Any help or suggestion are appreciated...

av8tor1977

My Feedback: (6)

Is the Husqvarna oil synthetic? If so, I would switch to a non synthetic oil like Pennzoil for Air Cooled Engines at 32:1, and run the hell out of it. (In the air.) Gas engines often take two gallons of gas or more to break in.

AV8TOR

Lifer

My Feedback: (1)

I run synthetic oils from the start and yes, it will take longer for the ring to seat.

JoeyCoates

The oil is semi-synthetic made for air cooled engines. I know there are other oils, and maybe some are better, but I have been using Husqvarna equipment for many years on our ranch and I trust the Husqvarna name. I would just think that their oil is good but certainly do not know that, I don't think it would be bad though. It is mixed 8.5 oz to 2 gallons which is the recommended 30:1 ration that DLE wants you to start with.

I guess it just needs time, it is mainly the lack of rpm's that has me concerned. As I said I keep reading that they should be making about what they are going to do right out of the box in which case I am down 300-700 rpm. I will get ti to the field and tuned then go fly. If it does not come up I can always put on the new unused stock ring on and see what happens. There is quite a bit of air leak hiss right now when it goes through compression, I am pretty sure that would begin to lessen once the ring starts to seat, I just was not expecting this little compression right off the bat.

I had it tied to the back of my truck with a ratchet strap yesterday evening while running it, as such I did not feel comfortable tuning at high rpm's with the movement and vibrations. I am going to try to go fly on Sat so I will take it to our club where we have proper equipment to keep the airplane still so I can tune the high end, there may be more in tuning, I just did not want to push it last night and harm something with a lean pull.

Cyberwolf

My Feedback: (4)

Myself I think I would drop Frank a line and get his opinion on things before I made any rash decisions. The engine may have another issue a person could be over looking.
Just wondering what sort of compression does it have when flipping it backwards?
I use Franks rings exclusively and outside from a dyke's ring the compression has always been very good from the get go,of course some have been better than others, but I don't recall ever having one like your referring to.
As a rule it's when you put the Bowman ring in the compression raises.

ahicks

My Feedback: (2)

Is there any possibility that you might have broken the ring on installation? You centered the ring gap on the pin in the groove?

Truckracer

My Feedback: (19)

I agree. There has to be a defect with either the ring, cylinder or piston that is being overlooked. Or .... there is an installation problem. Any decent ring, either stock or Frank's that I have ever installed had reasonable compression right after installation. In this case, I don't believe that additional run time will resolve the low compression issue until the mechanical problem is resolved. Perhaps the engine would have been better off had it just been left alone and run the way it came out of the box.

JoeyCoates

I was wondering if there were not some other issue as well like the cylinder being out of round but I do not have a cylinder gauge small enough to check, I do not think mine will get under 2.5" as it is really designed for automotive use. The ring is definatly not broken, it is on the piston in the pictures I took, it is also centered on the pin correctly. I know the Bowman rings are great rings, I am not trying to cast a shadow on them at all. I just know that I can flip it through compression with one finger right now with the engine in my hand pretty easily. I can put the stock ring back on as it does have higher compression and just let it run in, but I do not know that this would be correcting any underlying issue. It does have a bit more compression when turned over backwards, and the compression goes up substantially when I put some after run oil in it to wet the walls. It's just low if not really wet.

I just sent Frank an e-mail to see if he might be able to shed some light on what is going on, I know that he has a lot of knowledge. If the cylinder is out of round I could just put the stock ring back on and send it in to Tower, I am just afraid that they would tell me that "it starts and runs, let it break in to see if it gets better." There is nothing that I could do to fix an out of round cylinder other than to replace it on my own dime.

w8ye

My Feedback: (16)

Send the whole engine to Frank and let him look at it?

JoeyCoates

Maybe, he just responded to my e-mail asking a few questions. A few others on a different forum have stated that they have had similar issues and some run time cleared things up so that may simply be the answer. Again, if it were glow I would not be worried as they typically do pick up (at least in my experience) but sooo many people say that this is normally not the case on a gasoline engine.

On the plus side it starts super easy, idles at 1600 rpm's with no issues, could probably go lower, and transitions great. I would just be a little bummed to have a DLE35 that runs great but makes the same power as a DLE30, especially on a 3d airframe where the power is needed. I will get it sorted, just figuring out what to do next

JoeyCoates

Frank is sending me another ring to try (which does not suprise me at all given his reputation) so I will see if that helps matters any. I am going to pick up a cylinder gauge from my father house this evening to see if I can measure the bore. It is made for auto applications so I do not know if it will go small enough but I will figure it out. I would not be shocked to find that the cylinder is in fact out of round.

willig10

My question is why put a Bowman on to begin with? The stock ring is good and as equipped the engine is a powerhouse. Just saying.

GLenn

Truckracer

My Feedback: (19)

Glenn, I tend to agree. While the Bowman ring is a great product and my first choice when replacement is necessary, I don't rush out and install a Bowman ring in every new engine I have just for the enjoyment of doing it. The stock DLE rings in later engines are quite good for the most part and most cylinders are "round enough" for our use. Every DLE I have looked at or had any experience in the last several years had a ring that was quite acceptable as provided and installed by DLE. They provide good compression and power output with minimal run time, not at all like the early rock hard and seldom round DLE rings / cylinders were. I prefer to use the stock ring until proven it has a problem. Perhaps the OP would have been better off in this case doing the same as perhaps more problems were created during the change than were prevented.

Frankly I'm not sure where the mentality came from that every DLE engine needs a new ring and the reed block resurfaced before you run the engine. Hardly a day goes by that I don't read somewhere about a guy buying a new DLE and saying "I'm going to install a Bowman ring and do the reed block mod". Just some things that make me go Hmmmmmmmmmm as I scratch my head.

CARS II

My Feedback: (7)

I also did the same thing as JC with my 35 and also experince the same low compression that he did, my engine also run good and started easy, I have over 20 flights and change on the airplane/engine, the engine is doing just fine, I just turned the 35 to feel the compression on it and is getting there, definitely the compression has gone up but since I only have run about 1 1/2 gallons it is no way near been broken in and I expect that once the ring has seat completely the compression will go up some more.

CARS II

My Feedback: (7)

At the moment I don't see a problems with my engine and things are happening as they should, I wouldn't rush to any bad conclusion, it looks to me that your 35 is doing just fine, what it needs is more running time to notice the changes that we are looking for ( more compression ) and including myself more time learning on how the gas engines behave.

speedracerntrixie

My Feedback: (29)

I agree that this really should take care of it's self. That being said, at this point oil is helping greatly with the compression seal. The leaner you go the less oil, the less seal. I would suggest going back to a slightly rich setting and maybe add a tad more oil to your mix. As long as the engine is running reliably fly it. Bench running a gasser is of little value. You will also find that as a gasser runs in and seats it will begin to develop more power. It's not uncommon to see a 300-500 rpm increase over the course of 20-50 runs depending on the engine.

captinjohn

What would it cost for a new cylinder? Get one & try it. Good to have all the spare parts you can get for china made engines.

JoeyCoates

Well Frank sent me another ring and for whatever reason it has a lot more compression. Maybe I did something wrong putting the last one in, I do not know, but this one has some bump to it. I have not run it yet, but I suspect I will see a bit of a difference. Great customer service one way or another.

Truckracer

My Feedback: (19)

Looking forward to your report on how the new ring performs.

marksp

My Feedback: (9)

Adding a comment supporting Glenn's post, more for others considering the DLE35RA. My DLE35RA has 1 and only 1 mod. Changed the stock plug for NGK and nothing else. I haven't even touched a screw driver to either needle - nothing! Idles at 1600, pulls to 7600 on the ground and 8410 in air (Spektrum EVOA107 connected to RPM lead). Running premium non-ethanol fuel mixed with Redline Synthetic @ 40:1 w/1oz Seafoam per gallon. Xoar 17x8x3.

These new DLE's are runners - no mods required (except plug).

Cheers

PS - I actually picked up the Bowman rings for down the road...hopefully way down the road.

ascalise

I have a brand new DLE35ra that i put a bowmann ring in from the get go with very similar symptoms. After running a bit it has next to no compression. I have pulled the engine apart and looked at it and it is fine. It does run hot in the air as well. I was thinking about contacting him. This was all discussed on the other forum in the citabria thread. Let us know how yours runs with second ring.

Lifer

My Feedback: (1)

marksp,

What is the benefit of adding the Seafoam?

CARS II

My Feedback: (7)

Seafoam adds lubrication, as I understand it. I would also like to know why it is been used? And the expected benefits.

Truckracer

My Feedback: (19)

Just something unnecessary to spend more money on in my opinion.

marksp

My Feedback: (9)

For the record, I'm not suggesting or recommending Seafoam. It's simply a personal preference I have which I use in every non-emission controlled internal combustion engine I own. This includes my gas planes, 1/5 scale RC off-road, vintage tractor, Honda 2000i (2), weed whacker (2), lawn mower, gas trimmer, brush mower, 4 wheeler, motorized bar stools, '69 Camaro, '70 El Camino, & '69 280SL.

It's purported to reduce carbon build up. I can't definitively determine if it works or not because I've been using it so long, but I can say all of my gas engines run well and are super clean. Essentially I add an ounce to every gallon of non-ethanol fuel I buy so it's in my 5 gallon container before it gets distributed to the various 2-cycle "mix" containers for RC, lawn equipment, etc.

Cheers