ticketec

My Feedback: (2)

Thanks Trev,

Yeah Have to change the plus out and I used to buy from SDS back when they were cyclone! I was just about to put an order through them this morning! I'm trying to find the smallest spark plug boot to replace the originals. The cowl I have is just about 10-15mm too narrow to fully enclose the plugs and boots!

Thanks

dave

captinjohn

Is there two versions of this engine....with rear or top carb mounting places? Or are you talking about two completely differant brands or sizes of engines? Thanks Capt,n

Kahu1958

No not that I know of. I meant that different manufacturers have different setups, RCGF 50 is rear carb and XYZ 53 carb is bottom mounted (updraft carb)

Kahu1958

Spark plug boots add a lot to the overall width of these engines. Not many engine manufacturers give engine dimensions including spark plug boots.
It is easy to be caught out when buying an engine to fit a certain model over the net.

ticketec

My Feedback: (2)

Yeah, and in this case, It add a fair bit being a twin.

I can get the engine and plugs into the cowl, but not the boots[&o], but I'll keep looking for options.

Thanks

dave

kiwibandit

If you are only shy by a few cm, why not change the boot to a unit like you would have on your lawn mower engine ht lead? It is rubber (insulated) and comes with a coil spring to fit over the plug terminal. You will need to run a seperate earth lead to the engine casing as a return, but that is a piece of cake to do.
The other option is to cut some tear drop shaped access holes. This makes it easier to fit the cowling and provides access to checking the plugs.
I will hunt out a photo of what I did on my Sbach and one I did for a friend of mine.


[img][/img]

ticketec

My Feedback: (2)

Hey Kiwk,

I'm hoping that someone will pipe up and say that they have used those rubber boots and it doesn't cause any interferance issues, but the cutting of the cowl..... I'm leaving that option as my LAST resort! It's not exactly the best option in a scale wairbird[:@]

Thanks

dave

Kahu1958

I do wish the engine manufacturer had angled the spark plugs aft instead of up. it would fit better into scale horizontally opposed or radial engined scale models.

captinjohn

Rubber boots are not going to stop any inerferance.....hook the wire direct to the spark plug...tin it and solder it there. Do some good range checks before you fly. It may work fine. Capt,n

Ernie Misner

What is the narrow looking chamfered area on the top of each exhuast port? Does it extend on into the port opening?

Thanks,

Ernie

kiwibandit

Hi Ernie,
Yes. This small notch does go all the way to the cyl. I'm not 100% sure but I think it is to do with the way the gases are scavenged thru the engine. Gas has mass and at high velocity it takes a while for the gas to speed up and leave the cyl thru the port. This small notch allows the gasses to begin moving towards the exh port before the piston opens the main portion. The same process is in reverse when the port closes. The gases slow down gradually as the piston rises to the top of the port. As an example - when water is draining out of a bath or sink, if you place your hand over the exit, you will get a nasty whack as the water underneath tries to suck the center out of your hand. Repeat the process but control the closing of the plug hole and the water is made to slow down gradually.
In an exhaust system this makes for a much smoother flow of gas which allows the muffler to work more efficiently.

If anyone else is reading these posts and can add or amend if I am not correct, please feel free. I would hate to be giving out bad information.

Trev.

kiwibandit

On some of the early Zenoah engines, the cdi unit was the same set up as what you would find on your chainsaw or weed whacker. There was no shielding at all on the HT lead or the coil for that matter. The main source of trouble is when the ht voltage jumps a gap other than the plug gap. The em energy released from an unshielded spark blankets the rf spectrum which we see as glitches. All the rcexel modules run the earth return up the ht lead as a shield to minimise this em leakage. Keeps things nice n tidy as well with no extra earth wires to worry about.

Trev.

secatur

I have an XYZ 53 that i bought from Hobby King....Had about 2 1/2 hrs running and 2 flights in my 46% Smith Miniplane. I misses on one cylinder quite a bit, and is not developing full power, the Miniplane is 32 lbs and the engine with a 22 x 10 prop is enough...but just !). I have tried changing plugs to NGK, and all the other things I can think of (swapping ign leads, plug gap etc.) Still one cylinder misses (you can feel it on the exhaust ) and doesn't get as hot as the other one (about 20-25 deg difference.)
Anybody got any ideas ???
Thanks....

kwesty2008

Hello.
I have recently bought one of these engines and have had a lot of trouble with it. We think we have narrowed it down to the CDI unit as it will only fire on the one cylinder, but if you change the leads over, it will run on the other cylinder. It follows the working lead..
We have tried adjusting the timing slighlty but to no avail..
So i have contacted the seller, hopefully he will send out a new CDI and a couple of mufflers, as i have the same leaky welds you guys have.. Not great. I will keep in contact and let you know how i get on.
Funny thing is, i nearly went electric, but though against it.. Would have been flying by now...

Happy flying

olflyr

I have had this engine for about 3 mos. now and it has around 5 to 6 hrs. on it. Runs well with a Vess 21B prop pulling a PAU Bulldog with just enough power. Had the same problem with the subpar mufflers leaking and had Jtec build custom mufflers and they are perfect. Sound level is down and no more leaking. Like the engine, the sound, and it starts like a dream.

ticketec

My Feedback: (2)

Have any of you guy's check the timing on the engines from the factory??

I just checked mine and it has been setup to fire a 44 degrees BTDC ???

I thought gassers needed to be in the 28-32 degree mark? I has the same issue with my SPE thinking it was timed correctly from the factory and had been flying it for about a year before I checked it. Man what a difference it made to the engine to be correctly timed.

I'm probably only a few days away from the first start of the engine[8D]


Thanks

dave

Kahu1958

Thanks for that, I had not checked the timing but will now.

av8tor1977

My Feedback: (6)

You can use a rubber boot connector for the spark plug, if you use a resistor plug and ground the plug wire shielding to the engine near the plug. There is no resistor plug available (that I know about) in the CM-6 size/style plug however, so if your engine uses that size plug, you need to use a metal shielded cap. (There is a 10mm CM-6 resistor style plug with longer threads, but that does you no good, as to use it you would need to use a spacer and that makes the engine even wider.)

You might try using an adapter and going down to a 1/4 x 28 "Rimfire" type plug. These are the same thread size as a glow plug, and they make adapters to use them for either 14mm, or 10mm original plug sizes, and they make plug caps to fit them for the RCEXL plug wire. Might be a way to "narrow things down a bit" on a twin....

AV8TOR

ticketec

My Feedback: (2)

Thanks mate for the info.

It look like the only real solution that has been presented so far. I'm going to get the motor running happily first and then look at changing out the plugs. I've just bought some iridium plugs for it so I'll give them a go first.

Thanks

dave

ticketec

My Feedback: (2)

Hey Guy's

I fired up the XYZ today!!! It took about 4 flicks on the choke, and then about 3 flicks once I upped the idle to start. Runs beautifully!!!!! Really nice and smooth compared with the other 40cc singles I have run. No problems with one plug dropping out or anything that hinted at one cylinder giving issues, and that with the stock plugs in it. I have some iridium CM-6's here and i'll drop them in soon. Seems to have some really good power and I haven't played with the needles yet. I'll get my tach back soon from my flying buddy and post up some figures.

I've run about 1 liter through her so far and the idle is just amazing (low) for a brand new engine. Just uploading a really quick video of the first run now.

http://www.youtube.com/watch?v=1P8lc...=youtube_gdata

Thanks

Dave

Kahu1958

Glad to hear you got a good engine Dave.
I was just wondering though, on yours where does the magnet on the prop driver pass in relation to the sensor, on mine half the magnet sticks out beyond the tip of the sensor as it passes, is yours the same?

On other engines I have the magnet passes under the tip of the sensor.

ticketec

My Feedback: (2)

I'll check for you when I get home from work tonight.

I also emailed octopusRc in regards to the leaking exhausts and they said they would forward the pictures I sent to the manufacture and send me out a replacement set. Seeing as everybody elses are also leaking I don't expect that the replacement will be any better, but at least they are trying! Nice to see some support from asia block sellers!!

In the interim, I am going to run a bead of metalset over all the welds and hope that it will block the leaks up.

Thanks

dave

flynte

Just picked mine up at the postal outlet! Got a 26cc with it also. Have to get them unpacked after work tonight.

flynte

ticketec

My Feedback: (2)

Hey mate,

I had a good look at the magnet today and the whole magnet passes under the pickup on mine. Actually there is about 1-2mm of clearage between the edge of the magnet and the front of the pickup.

Ran another 500ml through her the other day and you can still notice how she is still bedding in. We got the tacho on the idle measuring about 1350 odd RPM with a TBM 22x10 prop, and at WOT with factory setting on the carbie, 5600rpm. I wound in the high needle a total of about 1/2 turn but didn't get a reading because the tacho went flat[:@]. next time I run the engine it will be fully encased in the cowl and also now has iridium CM-6's installed so we'll see how that goes.

Thanks

dave

Kahu1958

I have my engine running well now, it misses a bit at low RPM but quits if I lean it out any more. Good at higher RPM, possibly with the magnet too far forward the sensor signal may not be as positive as it should be. It still runs reliably and produces lots of power.