Slow and Steady

I received my repaired engine from Syssa earlier this week and as in the past, it is completely refurbished without charge; including crash damage. In looking at the engine, it dawned on me that while there are many bolted connections on the engine, only the muffler bolts loosen. Which does make me wonder if the muffler itself is the issue. Hopefully Todd will find a solution; but if not I will likely contact JTec for a custom one piece muffler. I will post my results if I go that route. I am definitely looking forward to putting this engine in the air again.

1 big skeeter

My Feedback: (8)

Todd,

PM sent.

1 big skeeter

My Feedback: (8)

Todd,

PM sent.

hobby_man

My Feedback: (8)

I wish Syssa had the time to ship the parts I ordered 10 days ago!

50%plane

My Feedback: (5)

Todd,

I just read in another thread that you had some sort of an accident. Just wanted to wish you well in the recovery process!

V/R,
Chris

bob_nj

My Feedback: (62)

hobby man > Good luck with that.
The last two parts orders I placed took a ridiculous amount of time to get here, and both
were not what I asked for.

When I do any business with them (because I have to), I send one email per day with a reference to how
many times the email has gone unanswered until I get some sort of response that the order was received.
Not everything available is able to be ordered on the website, and some things require some "personal" attention which is
incredibly hard to come by with Syssa.

I am being more factual than emotional believe me.
I've read all of the reasons why, and listened to those who are close to the situation and quick to defend.
That is their opinion and that's fine.
This is my opinion and it should be equally as fine.

They just received my engine yesterday 02/10/12 for evaluation.
We'll see if I can get it back before next broccoli season [&o]

mmlong

This sounds very similar to what happenedto Brilli engines. I still miss Scott and have one of his engines. Its one of the best in the 60cc class. I hope we Syssa customers can help this business through this rough patch. This engine shows great potential.
My last session left the muffler loose. Instead of just tightening it, I took it off the engine to check it out. After taking it apart I thought the very back plate seemed very thin. I'm thinking it's so thin that it sets up a vibration which in turn loosens things up. I found a piece of sheet aluminum about .100" thick(double the original). I used the thin one as a template and cut and drilled a new thicker piece. Next I happened to have the 2mm screws that were too long. I cut them for maximum thread engagement and red locktited them in. Also used high temp sealer and put the thing back on the engine. Here's the bad news............the weather took a turn for the worst and its going to be awhile before it's tested.
Bottom line this engine is a real screamer and takes the A J Slick anywhere it wants to go. The recommended prop(18.5x5.5) has instant response. My buddy says," I wish mine would pop like that".
We'll figure this muffler out and move on.
What can we do to help Syssa move forward? I want to help!

ahicks

My Feedback: (2)

mmlong, like the thought regarding this muffler deal. That would jive with what I see that's going on.

Rather not take the wait and see aproach either. This thing isn't rocket science. If we get enough ideas pooled, we'll come up with something that works sooner or later. Then it's Todd's option regarding if he want to use it in production. I think he's got his hands full already. No time to work on something like this - especially if we're working on it ourselves. Spring will be here soon enough. Then we'll get to try some of our ideas.

bcchi

I would like to help also,What could I do. I have a Syssa engine ready to test fly but turned winter here. No snow but cold and windy. I am going to send Todd one of my new little lighter ignitions.Do you no if he ever made a different prop hub the the first one.
I no what its'like to be behind and overwhelmed. Been there done that.
BCCHI

Antique

My Feedback: (4)

If the muffler has crush sleeves inside on the bolts no amount of covering on the outside will do anything to help keep it on...If not, it should have....

ahicks

My Feedback: (2)

There are crush sleeves inside, but not following what you're saying about covering? The stock muffler is shaped like a cup, with a backplate forming a lid on the side furthest from the enginge. The bolts go through the back plate, into the sleeves, then through the "cup" and into the cylinder. Have to see one i guess...

On mine, those crush sleeves worked their way right through this back plate. mmlong's idea of that plate doing some serious resonating could cause what I'm seeing....

Will take some pics the next time it's apart I guess...

mmlong

I wanted to add my next revision if the thicker plate fails. I hsd another engine that kept shaking the muffler loose. After serveral trys I put JB Weld on instead of lock tite. It flew the reat of the season that way. I would have done this change that way, but I'm out of JB Weld. The only problem with the JB was I couldn't get the muffler off. I ended up using a torch with alot of heat. It came off and the engine ran the same after the heat. I was concerned with the heat wraping somethig on the cylinder. I'm guessing there is a riisk involved. I have no idea how to post a photo so I can't help that way. If I knew what I'm doing with this computer, I would give myself a better name then mmlong. My friends call me Mike.

Slow and Steady

Any body try red loctite? That will be my next action before ordering a muffler from JTec.

bob_nj

My Feedback: (62)

Lemme know which J Tec fits?

Thanks
Bob

Zippi

My Feedback: (10)

I have not ran my engine yet but I drilled a 1/16" hole in each bolt head for safty wire and applied Permatex High-Temp RTV Silicone Gasket Maker to the bolts. I'm hoping this will keep things together for a while.

Joystick TX

Red had been tried. Some have had sucess with it, didn't work for me.

ahicks

My Feedback: (2)

I've used red Loctite every time I've had it off. Since we started playing this "tighten every time you run it" game, it's proven totally ineffective at keeping the muffler on tightly. I do use Permatex on the muffler to cylinder joint, and that's working well.

On mine, I'm standing by the theory that the bolts aren't unscrewing. The muffler is collapsing. The rear plate is now concaved inward. As mentioned, those alum. spacers inside the muffler have pushed right through the plate forming the back side of the muffler on mine. The question I have is why, and I think Mike has a pretty good answer...

The next time I have mine apart I'm going to try a steel washer on both sides of that plate to try ans support it better in the area those posts contact it. If that doesn't work, I'll be looking for another muffler as well. FWIW, -Al

Joystick TX

IMO the problem is due to several mechanical issues with the engine/muffler interface. A fix will not work until all of them are addressed. I think the main problem is that the engine and muffler are acting like two pendulums that have different resonant frequencies, which causes them to rotate out of sync, which loosens the bolts. Imagine yourself holding the engine and rotating the muffler back and forth, alongthe axis of the crankshaft,to get an idea of what may be happening. The engine firing pulses cause the "vibration" that sets the two masses in motion and the lead and lag of the two masses causes the bolts to unscrew. If the bolts can't turn, then there will be wear on the engine cylinder or the muffler.

Mike Miller

I concur with Steve on what is likely the baseline issue here. I have not had the issues with my mufflers loosening up yet, but continue to monitor them (or will when the blasted weather warms back up).

My thoughts on a possible "fix" are to secure the exhaust pipes somehow to the crankcase of the engine. I suspect that a twisting force is working on the muffler assembly causing it to loosen. Watching my DLE 20 shake wildly at idel when mounted to a profile plane reinforces this. That engine is oscilating wildly below 2500 RPM, caused by the acceleration/deceleration of the reciprocating parts and the torque that the airframe is flexing to.

I may have a go at fabricating a brace, even though I have not had the problem. An ounce of prevention possibly?

Mike

Mike Miller

Sorry, server issues caused a double post

Mike

ahicks

My Feedback: (2)

OK, so going with the "oscillating" engine theory, wouldn't we have that same motion present at the motor mount bolts? If anything, they have even less area to support the weight of the entire engine and muffler. With the same movement we're considering at the muffler, shouldn't we be seeing something going on there as well? Is anyone seeing anything there? I'm not, but I suppose that might be the firewall and stand offs are flexing enough to avoid that happening. Dunno....

Just thinking...

JohnB96041

Guess I am one of the lucky ones. Had my engine since Oct of 2010. Mounted on a Funtana 125 and has never been removed for anything. The muffler is still as tight as the day I got the engine. It has the nordlocks on both bolts attaching the muffler to the engine. Engine and plane have had about 3 gallons of fuel run through it with many successful flights. Waiting on some nice weather to test all the telemetry and the DX8 system.
Just a thought, for a new engine from Todd, I would be willing to send in this engine for inspection as to why the muffler has not come loose yet.

dr_boone

JohnB96041how is that possible I have has mine since December 20, 2011 and am on my 3rd gallon of fuel. Just kiddin.
I'm running a macs header and composit pipe and nothing has came loose on mine.

Joystick TX

You won't have the problem with the motor mounts as much, but they are subject to the same oscillation and can work loose.

There are other factors such as mount spacing and rigidity of the mounting system that enter into play. Syssa engines using a tuned pipeshouldnothave as much pendulum effect as the standard muffler since it will be less likely thatitwillget out of sync with the engine. I suspect the tone inserts will cause moretwisting,due to more mass being at the end of the stingers which will act as a lever,and the resonant frequency will also change.Theforces will be different at various RPM's and there will be one harmonicfrequency where thetwisting forceswill be the greatest and that is the one that will cause the most problems.If you run your engine at that frequency, you will have more problems. The engine, muffler,standoffs, engine mounting box, and airframeall make upa"system" thatwillresonate at some frequency. I suspect that is why some people have more problems with loose mufflersthan others. It is not a simple issue. You may be able to run the engine for a hundred hours on a test stand with no problems and have the muffler come loose after a fewhours on a plane.

I thought about trying to tie the muffler stingers to the cylinder to dampen the twisting forces, but haven't figured out a way that would not cause other problems.

The DLE engines have side mounted mufflers so they don't have the sameforces acting on them as rear mounted mufflers.

JohnB96041

At least there are 2 of us that have not had the loose muffler problem, so far. The weather and a bad shoulder have keept me from flying since last May. Looking forward to some good flying weather so I can get back where I was. Shoulder surgery really slows a person down for a while. I think I have about 20 or so flights on the engine.