flygilmore

I was thinking about getting the EI unit/hall sensor from Hobby City for a couple of projects-what are you guys using to "time" the spark and where would I get info for timing of different engines? I have a couple of Ryobis and Homelites along with a couple Echo 21.2cc. Would a regular timing wheel found on the Internet work?

Thanks a bunch!!

JIMARRINGTON

Timing is timing. Any wheel off the internet will work or make your own. I use the one that can be downloaded from CH ignitions. I have an XYZ ignition on a Poulan 25cc. Start at 28 degrees before top dead center and adjust as necessary. Runs great.

Jim

monster46

Do you know if those EI units have auto-advancing timing?

combatpilot

I installed the xyz ignition on my ryobi engine. first thing i noticed is it now starts great. just a small flip an wham its running. also the idle improved drastically. It idles so smooth and slow i can almost count the blades going by lol. this is due to the fact that it has a wonderfull timming advance curve. it will retard at low idle and advance through the rpm range.

To time you need a degree wheel and a way to find TDC. any degree wheel will work as long as it can be fixed to the prop hub and not allow the magnet to change position when it is taken off after timming. I use a dial indicator to find TDC. sure you can look into the cylinder and see when the piston is at tdc but you can still be many degrees off of tdc as there is several degrees of crank travel at tdc with no piston movement. the idea is to find the center of this dead spot in piston movement on the degree wheel. this will be true tdc.

With a dial indicator installed and a degree wheel installed rotate the wheel through the rotation to the piont just where the pistion stopes moving. note this degree. keep going till the piston just starts moving again and note this position. half way between the two noted degrees will be true tdc. set your degree wheel to 0 at this point. rotate it through again and recheck it as it takes some fooling with to get it right. So lets say there is a 4 degree dead spot where there is no piston movement when the crank is rotated. so what you finally want to acheive is when rotating it through the piston stops moving at 2 deg BTDC and starts moving again at 2 deg ATDC. If you haqve this set up you now have true TDC set on your degree wheel.

Now install the ignition and set the sensor over the magnet when at tdc. next rotate it through till it sparks. when it sparks look at the degree wheel to see what the timming is. now adjust your sensor to spark 28 deg btdc when pulled through slowwly by hand. your engine will now be timmed

here is how i install the dial indicator. i used an old plug modified to accept the dial indicator.



Ok if you dont want to do the dial indicator method you can take the muffler off and rotate it through till the exhaust port just opens. note this and keep rotaing it through till the exhaust port just closes and note this number. the difference is the port timming. ok take the difference and divde by two. there should be an equal number of degrees before and after bottom dead center from port open to port closed. in other words if your port timming is 140 deg then there should be 70 degrees before BDC and 70 degree ABDC.
so if you set your degree wheel to where the port opens 70 degrees BBDC and it just closes at 70 deg ABDC then it will be set again at true tdc.

BDC is 180 degree so if your port timming is 140 the port should just open at 110 degree and just close at 250 degree

here is my degree wheel. i had a friend cad it up and then i hand numbered it. notice the marks for port timming are same dgrees before and after BDC

captinjohn

combatpilot....good photos with some good data there! Thanks for sharing. Capt,n

JCaste

Very useful info here!
Since I discard buying one of the fancy and expensive EIs, I was about to open a post to compare XYZ's ignition and the homemade ones seen here.

After some reading, I believe the biggest difference is the ability to set a custom timing curve on some of the homemades. However, if the XYZ works as good as I'm reading, there's just no rival (at least for me). Cheaper, ready to use, and great functionality. Besides, for most models & uses, I doubt there's a real need to make a custom sparking pattern.

I have a couple of questions...
- If I understood right, magnet location is irrelevant. You just have to set the hall sensor so that the spark occurs at 28º BTDC, isn't it?
- Which hall sensor did you use?

captinjohn

Most ignitions come with the sensor/pickup, or at least for a few greebacks more ...it is yours. The magnet is what triggers the spark as it passes the sensor. The position of magnet is some-what got to be in the right place. Fine timing is done with the sensor/pick-up. Some have a bracket that allows for this. I myself like to install the magnet on a timing ring that slips over hub. It has a set screw to lock the ring in place for correct timing. Capt,n

JCaste

If possible, I'd like to hear a more extended opinion of the EI. Is it well built? How much flight time does it give? But what matters most, how does it work? [X(]
Sooner or later, I'm sure someone at RCU will rip one apart and come with a way to mod and improve it.

I don't know if this particular EI comes with the sensor, but I browsed hobby city a couple of days ago and I would say there were several hall sensors; I wanted to know which one did he pick.
And I might be missing something, but I don't see why can't you put the magnet anywhere in the hub and then just move the sensor to the right place and hold it with one of those sheet metal bands that are tightened with a screw (I just don't know the name for that). Of course, you could always bolt the sensor to the engine and then use your solution, which seems a more elegant way of doing it.

combatpilot

The thing dont like the most about this unit is it has a plastic housing instead of the aluminum ones you find on other units. Other than that this unit is great for the price. It is so cheap why would you possibly bother building one other than the challange of the project and the pride knowing you built it? it already has a wonderfull spark advance curve that makes a ryobi idle wonderfull. this unit is well worth the pirce and i really dont think you will be dissapointed. the ignition is 25.23 and does not come with the sensor. the hall effect sensor is 7.59 and this is the listing description

http://www.hobbycity.com/hobbycity/s..._HP-50_Engines

With shipping added in it will come to your door for just under 40 bucks. For that price if your really unhappy with it which im quite sure you wont be how much did you really lose? I lose that much at 7-11 every week lol.

.

The magnet position in the hub is not really important. just as long as it is in a spot to where the sensor can be mounted and adjusted. yes the sensor can be held on with a hose clamp and it is a very common practice to do it this way

As far as how much flight time does it give. that all depends on how large of a battery you have. a 1500 mah battery will give enough flight time that you will be tired of it

this unit works great and you will not be dissapointed.

Aussie Maddog

My Feedback: (16)

I have run both XYZ (the blue one above) and the Rcexl (generally a metalic/silver case). The XYZ is 6volt and Rcexl 4.8 nominal volts.
Many manufacturers use the Rcexl ignition and I think it's the better quality of the two.(And more expensive). The hall sensors are not interchangable as the Rcexl has a futaba plug and the XYZ it's own connection.
The XYZ is now available to fit CM-6 plugs from the Turnigy 50cc engine.
The Rcexl is manufactured with a wide range of caps to suit different plugs.(Twins also)

You can put the magnet where you want BUT for example, if you were installing it on an engine with a front mounted carby and the magnet was on top then the sensor would interfere with the carb.
It's not about where the magnet is, but where you want the sensor mounted.

combatpilot

Thats true on the volts but the xyz does say 6 volts but absolutly no more than 6 volts

JCaste

Thanks for the description, combatpilot.
Apart from making a couple of guitar stompboxes, I've never really liked electronics, so there's little reward for me after building an EI. If time and cost enter the equation, it's even more clear I'm not going to build one.
BTW, guitar techs use a fine sheet of copper with adhesive in one side to cover the guts of a guitar and shield it from interferences. Perhaps that could help here too to prevent noises... (or moving the circuitry into a full metal box).

Aussie, is the Rcexl available somewhere? If the plug type is the only problem, it has an easy solution. So, the XYZ comes with several plugs, or a "general plug" whichi fits most?

Aussie Maddog

My Feedback: (16)

The Rcexl is also available at hobbycity(Sensor sold separately), but I don't know which plug it's for. Hi-model sell a Rcexl unit (with sensor) as a spare part for the DL-50, CM-6 plug.
CH ignitions sell the Rcexl unit in the USA and I imagine will offer service/advice/warranty. With the Chinese companies, you take your chances.
My XYZ ignition fits a CMR6A plug (10mm) and BPMR6F plug (14mm) and as previously mentioned, you can purchase the Turnigy 50cc CM-6 unit.

Giving myself a plug here, I have a setup kit for the Rcexl ignition in the Gas engine classifieds

JIMARRINGTON

I have 2 XYZ ignitions. One I bought from Hobby City, the other I bought from Southeastrcengines.com. He is the US dist for XYZ engines. One of the XYZ ignitions quit on me after only a few flights. I believe it is the one from Hobby City. I replaced it with a RcExl igntion from again Southeastrcengines.com. I prefer the RcExl ignition. It seems to be of better quality. From Southeastrcengines.com they are both the same price. Shipped to my door was $51.00 and I have a US company for warranty if needed. I will not buy another one from Hobby City.
BTW, the RcExl is on a Ryobi also and it flew great at our Big Bird last weekend. Have it on a 4 star 120. Great combo.

Jim