rjmods

My Feedback: (7)

Recently got out my brand new Moki 180 Gas Ignition to put in a 85" Gee Bee Y. I set it up on a test stand with the spark plug removed so I could see the spark occurring. Didnt matter what I tried I could not get a spark out of it, so moved on to a lateral approach. I found an old bar magnet that I had and manually passed that over the sensor (which I had removed from its mounting on the motor) - guess what - a nice fat spark, so thinking that it may be gap related I passed the sensor over the magnet mounted in the prop driver - NO SPARK.
Next move was to obtain some small rare earth magnets and try these - I manually passed one across the sensor and was rewarded with a big fat spark, all this did was to frustrate me even more as the system appears to work but when all mounted on the motor - Nothing.
Anyway to make it easier to hold the small rare earth magnet I got a small pieace of timber and drilled a hole to mount the magnet. Once done I then tried it across the sensor yet again and guess what NO SPARK now this was the same magnet that worked not 30 minutes before, SUDDEN THOUGHT I turned the magnet end for end mounted it back in the timber and once again passed it over the sensor - NICE BIG FAT SPARK.

It would appear that although a magnet may be magnetised and able to attract onther metalic items its "force field" does have direction.

So now I have mounted a second magnet in the prop driver which gives me a nice fat spark I will be able to test run this motor at the weekend.

Hope this helps someone out there.

RJM

Rcpilot

My Feedback: (78)

Walt and Sage

That is interesting...
Just one more reason why good gas motor manufactures RUN their motors at the factory...

DMcQuinn

My Feedback: (13)

Yes, the orientation of the magnet does make a difference. I think 3W now makes an ignition that has two magnets in the hub one with the north pole exposed and the other one with the south pole exposed. The ignition picks up both magnets and can use this information.

Another thing I learned the hard way if you heat the hub with a torch, it destroys the magnet. Apparently heat can ruin a rare earth magnet.

pe reivers

The sequence of both magnetic field directions still is important.
Yes, field direction (N) or (S) is very important for the switching of the Hall sensor. And yes, lack of final assembly control is important.
And no, the engine does not have to be run if the manufacturer knows his business and has ample quality control.

kenhiraihnl

most of the posts regarding optimizing engine performance has to do with working the hi and low needles, prop selection, etc...are there any instructions or guidelines for adjusting the hall sensor (timing)?
-ken

RC Extreme power

My Feedback: (24)

28-30 degs before top dead center for most RC Xell or CH ignitions

Others are form 3-6 mm before top dead center

Milton

kenhiraihnl

thanks...just to make sure that i understand...when i set the piston at tdc, the magnet should be past the hall sensor by 28 to 30 degrees?
-ken

pe reivers

Not exactly. The spark should occur at 28° BEFORE tpp dead centre, when the prop is rotated slowly.
This is for retarding ignitions like RCexcl. Advancing ignitions shouls spark between topdead center and about 5° before top dead centre.

RC Extreme power

My Feedback: (24)

Read this it should answer all your questions
http://www.ch-ignitions.com/CHinst.html

Milton

pe reivers

Not quite, but nearly all.
My 50cc racer with fixed ignition had about 20° advance, but with it's 10 hp, it would turn circles around a DL50 had it been on a plane. GP racers (50cc) with 16 hp had no more advance than 24°. A lot depends on engine design and compression chamber design, turbulence and rpm. Stuff that can hardly be predicted, so you have to learn how to read the plug well, and get a good feeling how far you can retard the ignition and still have all the power that the engine will give.

kenhiraihnl

hi pe...i just saw your recent post in the engine conversions sub-forum...

"From a retarded setting, increase timimg little by little, until you find best rpm. that is the setting you will want to run.
If you advance further, rpm will remain the same, but the engine will start to run rough, and plug tuning (judging) will become confusing. There will appear a burnt ring at the end of the central electrode. Retard ignition again until this ring disappears."

i think that is the instruction/guideline that i was looking for...thanks...ken

sjm...sorry for hijacking your thread...i got carried away...ken

rjmods

My Feedback: (7)

Hi There I was the original poster for this item and was wondering if you may be able to help on a related issue.

Brought this brand new Moki a couple of years ago and now have a model in which to put it. The ignition system that came with it is simply labelled S&P 0477.

Do you know of this ignition system and are you able to supply any information regarding it.
I did test run my Moki at the weekend with no problems. Certainly the gas is more fuel effecient than the glow but then Im not complaining - I love all 14 of my Moki's.

rjm

pe reivers

I think you are talking of this engine


I used to run one, and was not impressed by the ignition. In the pictures at rcshowcase.com I also see the "fix" with the hose clamp.

I have no data on the ignition, other than that it uses a steel proximity sensor (not a hall sensor) to fire.
The engine is no longer on rcshowcase's website, but they may be able to help you out.

captinjohn

Question...Will a RC Xell pickup sensor work on a CH ignition? I know the connector may need to be redone. Thanks Capt,n

thevirginian

Is there a way to check if a hall sensor is bad? I am heving trouble lately with my ignition on my Brison 6.4. I get 5V to the Dean connector that connects the pulse switch to the module. If I ground the the Dean and interrupt it I get a spark, which tells me the module should be good. But how can I tell the sensor is good or bad?

pe reivers

First checks:
if it is a hall sensor (uses magnet with right pole up, and will fire if moved very slowly) or a proximity switch (uses steel part proximity, will not care which side up, and will fire when passed very slowly) or an induction pickup coil (uses magnet, right side up, but needs to pass fairly fast).

The test you did already shows the sensor to be bad, probably due to creating a spark without proper ground connection. The spark energy instantly kills the sensor.

thevirginian

No, I didn't fire the plugs without ground. But what I did was to connect the battery backwards, by mistake. Yes, it was possible, due to an universal plug. Now, when I plugged it in wrongly the positive (red) lead was still in the center of the plug. Only the ground (black) was reversed and connected to the outside lead (orange), which is the signal, I believe. Luckily it didn't fry the module (I hope). But it looks like the sensor is toast. I guess I need to call CH and get me a new one.

captinjohn

Look at the connector you plugged together, as yo say backwards. It is possible to plug them together backwards...but I think only 2 of the 3 pins are used. Backwards the pins needed for a complete circuit may not line up...so no power...no damage. MAYBE! Capt,n

thevirginian

Thatwas my thinking, too. But the gentleman at CH-Ignitions meant I could have damaged the sensor, though. So, I am going to order a new one, only 7-8 bucks anyway.

captinjohn

With no power going to the CD box, how could it possibly harm sensor? I would shure like CH guys explain how that could happen. Capt,n

thevirginian

Well, captain, I didn't want to argue with the nice gentleman from CH-Ignition. I guess he's the one who builds them, as far as I understood from our conversation. I ordered already a new one.

captinjohn

I forgot to add...the sensor leads are sometimes quite fragile and can get physically damaged. I suspect that is what happened or th sensor went bad on its own, not your fault. the use of clear silicone rubber where the wire meets the probe can help. Capt,n

thevirginian

I hardly can't wait to test the new one, once received. Hope that's all the problem with this ignition.

pe reivers

In reply to capt'n
sensor damage is the main failure mode of electronic ignitions. Just be sweet to all leads, protect them from any harm like heat or mechanical damage. Also protect them from high power surges, and your ignition will live to spin some more yarn.