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CH Ignition conversion on G26

Old 08-21-2009, 09:07 PM
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Scooter04
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Default CH Ignition conversion on G26

I am trying to make sure this ignition is not smarter than I am. Maybe I am making this too difficult, please see what you think.

I am converting a G26 mag to electronic ignition, as I am sure many have done before me. I have read the instructions that came with the CH Ignition (as well as have worn out the search feature) and may be confusing myself. The included instructions seem to be meant for many applications, and the specific Zenoah instructions are to convert a factory electronic ignition to a CH Ignition.

In a nut shell I have located TDC and both sides of the dead spot. I then centered in the dead spot and took the provided degree wheel and put the "zero" in line with the magnet on the new rotor. If I understand correctly, all I have to do it locate the sensor, 30 degrees before TDC. This would mean if I locate the "0" at the magnet location on the rotor, I need to locate the sensor in it's slotted bracket, 30 degrees to the left on the degree wheel when viewing the engine from the back. Seems simple enough.

What has me second guessing, is that the sensor is slid all the way to the right in the slotted bracket. Which means if I needed less than 30 degrees before TDC, I would have no more adjustment.

Can anyone confirm I know what I am talking about or that I am way off base?? How close is close enough? Once I mount the moter back on the plane it seems about impossible to adjust accurately, so I am trying to get it right the first time.

Maybe it's late or the fact I have never had to set timing on one of these . . . .

Thanks guys
Old 08-21-2009, 09:48 PM
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w8ye
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Default RE: CH Ignition conversion on G26

Put the sensor in the middle of its adjustment range and secure

After you have found true Top DEAD Center and put your pointer at zero on your degree wheel for TDC

Back up to 28 Degrees BTDC wwith the crankshaft

This is where you want to locate the trailing edge of the magnet as it is coming out from under the sensor

Get your ignition going with the base of the spark plug grounded to your engine with a jumper wire

turn the crankshaft in the direction that the engine runs and adjust your hub for the spark to fire at 28 dgrees before top dead center
Old 08-22-2009, 08:38 AM
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mpascual
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Default RE: CH Ignition conversion on G26

Wait a few days. RCEXL is going to supply to all distributors a kit for set the timing on their RCEXL ignitions. (Hall sensor test kit):
http://www.dlenginesaustralia.com/dl...&productId=187
I've done what you're trying one year ago:
http://www.youtube.com/watch?v=LHPfudm0vxI
I was lucky because i set the timing without any reference , and engine goes well at first run.
After a year of use, the owner of this engine is very happy with this conversion...... It flies a Funtana 140 Sebart with canister exhaust. 18x8 menzS prop @ 7.200 rpm...

Regards
Old 08-22-2009, 11:20 AM
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Scooter04
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Default RE: CH Ignition conversion on G26

Thanks guys. I since found some more pictures and glued my degree wheel to 1/2" peice of plywood so that I could bolt it to the engine. I have measured from the front and the back with the same results, so I am going to mount it back on the plane. Wouldn't be so bad if the engine was on stand offs, but it has a mounting plate that sort of blocks access to adjusting after the fact. Hopefully it's close enough. I fired up the ignition system and everything seems to be working the way it should.

That new test tool looks like the ticket in the future.

Thanks again.
Old 08-22-2009, 12:03 PM
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Scooter04
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Default RE: CH Ignition conversion on G26

W8ye, also good advice on the "trailing" edge of the magnet. I wouldn't have thought about that, but once you have everything fired up it clearly sparks as the magnet leaves the sensor. I don't see how you would set it up without turning on the system and turning over by hand.

Thanks
Old 08-22-2009, 04:37 PM
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Scooter04
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Default RE: CH Ignition conversion on G26

Well, it fired up by hand after getting it choked properly. What started this is a bad stock magneto set up, so I have only got it started once before. Today I got it started half a dozen times by hand which is what I was hoping for. A big thanks to CH Ignitions. They were friendly as can be on the phone and actually helped me trouble shoot the bad one. They could have just said it was bad and tried to sell me a new one.

Idle appears to be a little rough and too fast. It gets down to about 2400 with a Zinger 16x8 before it dies. Top end is at about 6400 with same prop. Carb is at factory settings. I have an 18x6 Xoar for after a little break in. Running Pennszoil air cooled at 40:1.

How do you really know that you have the timing set just right?? I ask this before I go and start tuning the carb. I checked the thing 4 or 5 times and followed the procedure w8ye suggested. I feel pretty confident I got it right but just curious. I assume you chase the carb all over the place and can't get a good tune.

Thanks
Old 08-22-2009, 06:01 PM
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w8ye
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Default RE: CH Ignition conversion on G26

My gas engines all have the needle valves on the prop side of the carb.

I've messed with tunning engines since I was 6 yrs old. I can tell if they are rich or lean mixture wise. I would adjust a little and run the gas model engine to see what I had. Over and over again until I got it right.
Old 08-22-2009, 07:45 PM
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Default RE: CH Ignition conversion on G26

The ignition should spark at 28-30 deg BDTC with the degree wheel installed and you turn the engine over slow by hand
Old 08-24-2009, 02:35 PM
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Default RE: CH Ignition conversion on G26

For tuning the carb this is the procedure I've followed. Worked first time I tried it and I've used it ever since (got it from Mark Fuess):

"Set the low end & high end needles to about 1 3/4 to 2 turns each. Choke the carb or prime it, until the carb is wet. Fire up the engine and let it warm up. Let's set the top end first since it's the easier of the two. Go to full throttle. Adjust the top end needle for peak RPM. Leave it wide open for about a minute to see if it changes any. Should the engine go lean, open the low end needle slightly, if this doesn’t work... you will have to adjust the needle valve inside the carb.( I will explain this later) If the top end runs OK, then slowly pull the throttle down until the engine begins to "four cycle" hold the throttle there. Adjust the low end needle until the "four cycling" barely stops. Now lower the throttle more until it "four cycles" again, and adjust the low end again. Keep doing this until you reach full idle. Now, from full idle begin to throttle up until the engine starts to bog or hesitate. Open up the low end needle just enough to eliminate the bog or hesitation.
When this is done right, you will be able to set the throttle in any position and it won't four cycle, plus you will be able to transition from idle to full power without any hesitation at all. Now, for easy starting it's best to have the low end a little rich and it will four-stroke a little."
Old 08-24-2009, 05:39 PM
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Default RE: CH Ignition conversion on G26

If the engine will start, make a mark where it is now and move the pickup switch toward TDC a tiny bit at a time and tach it. You will find a spot where the rpm doesn't increase anymore. I beleive C&H has that in their instructions in more detail. You can always go back to the starting mark, if you are happy with the way it runs there. I set mine at the recommended 28deg and let it alone. It develops plenty of power there and starts fine.
Old 08-25-2009, 10:32 AM
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Default RE: CH Ignition conversion on G26

Don't expect too low and reliable an idle plus with such a light prop until the engine has some more run time on it. That top end rpm of 6,400 is low for that engine / prop combo, and I suspect that your ignition timing and carb adjustments might need some fine tuning, or the tach used might be off. On a Zinger 16x8 prop max. rpm should be in 7,000 plus region running on the very restricted stock muffler.

Karol
Old 08-25-2009, 03:05 PM
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Default RE: CH Ignition conversion on G26


ORIGINAL: karolh

Don't expect too low and reliable an idle plus with such a light prop until the engine has some more run time on it. That top end rpm of 6,400 is low for that engine / prop combo, and I suspect that your ignition timing and carb adjustments might need some fine tuning, or the tach used might be off. On a Zinger 16x8 prop max. rpm should be in 7,000 plus region running on the very restricted stock muffler.

Karol
I was thinking that number is low also. My SV26 with spin that prop over 8,000 with it's stock pitts. I think the G26 is a stronger engine. How much is an Abell RC muffler worth over the stock one?
Old 08-25-2009, 05:38 PM
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Scooter04
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Default RE: CH Ignition conversion on G26

Based on what I have read, I was thinking the numbers were low as well. I made sure the needles were set per the manual and did the best I could on the timing. I will work on the needles a little bit and see if the rpm comes up. If I don't seem to get much of a reaction out of the high end needle, I am going to assume the timing needs tweaked. Starts consistently with the new ignition. What stinks is with the motor mounted, I can't get in and adjust the timing. Not a big deal, just eats up time if you know what I mean.

One other thing to note is that in it's current "un-tuned" state," I don't get much change from about 5/8 to full throttle. Servo is moving carb the full range, but not much change in rpm. I am assuming leaning the top end will change this, but I was surprised.

I'll try tuning in the next couple days.

Should I put the 18x6 on or stay with the smaller prop for break in??

Thanks for all the help.
Old 08-25-2009, 06:23 PM
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Default RE: CH Ignition conversion on G26

Your engine will need a couple hours of general use before you start to compare it with those bench marks

It is rather typical especially on a new engine for the last quarter of throttle travel to not show much response. Up in the air and on a plane that will speed up, you will get a better showing for that last bit of throttle but it is still not so pronounced as lower throttle settings.
Old 08-25-2009, 10:51 PM
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Default RE: CH Ignition conversion on G26


ORIGINAL: mrbigg


ORIGINAL: karolh

Don't expect too low and reliable an idle plus with such a light prop until the engine has some more run time on it. That top end rpm of 6,400 is low for that engine / prop combo, and I suspect that your ignition timing and carb adjustments might need some fine tuning, or the tach used might be off. On a Zinger 16x8 prop max. rpm should be in 7,000 plus region running on the very restricted stock muffler.

Karol
I was thinking that number is low also. My SV26 with spin that prop over 8,000 with it's stock pitts. I think the G26 is a stronger engine. How much is an Abell RC muffler worth over the stock one?
I don't own a G26 but on my G23 an Abell muffler gives about 600+ rpm over the stock unit.

Karol
Old 08-25-2009, 11:04 PM
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Default RE: CH Ignition conversion on G26

Though somewhat smaller in size a 16x8 prop produces pretty much the same load on the engine as a 18x6. Ideally you should break in an engine using a prop one size smaller than normal which in this case would be a 17x6 or a cut down 18x6. After the engine has had some amount of run time and fitted with a less restrictive after market muffler it should be propped to run in the 8,500-9,000 rpm region as that is where the G26 really shines.

Karol

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