Nikolas K

Hello![sm=teeth_smile.gif]

I have bought an RCExcel CDI ignition with everything that is needed to convert from glow to gas a four stroke ASP 52FS engine. I have the CDI module, a 1/4-32 spark plug, a magnet and the Hall effect sensor.
The most important thing for the beginning is installing the hall sensor on the engine. For that, the ignition came with two different sizes of sensor holders. I will obviously choose the smaller one, since the engine is small. In order to be able to alter the static timing, I am thinking of using a hose clamp on which I will attach firmly the sensor holder. THen, the hose clamp will be screwed on the front bearing place and it will be easy to rotate it once you will unscrew it.

What do you thing is the best method of attaching firmly the sensor holder on the clamp? Is it good if I epoxy it? But for that I need to know what material is the holder. It seems plastic, but what kind?

Also, is it good if I epoxy also the magnet on the prop driver? The instructions state drilling a hole just a little bit smaller than the magnet (3.9mm) and then just to squeeze the magnet in. But it seems to me that the prop driver of the 52 engine is just too small to rely on squeezing the magnet only.

Thank you.

HunkaJunk

I have done exactly that, I used JB weld to attach the sensor to the hose clamp, many flights and it still has not come off.

I made sure to get the JB weld through the slots in the hose clamp and through the mounting holes on the sensor.
I have never tried to hold the magnet on with glue, I always drill a hole and press fit the magnet in.

w8ye

My Feedback: (16)

http://jbweld.net/index.php

Scota4570

I just drill a hole in the hub that fits the magnent. Usually 1/8" for a nominal 1/8" magnent. I have not messed with pressing them in. Magnenets are very had and tend to crack. A little slop is not a problem. Once you have to bust out a magnent it is a problem. Diamond dental burrs come in handy. Anyway I just CA them in place. A couple of little stakes, in the hub, with a center punch and you are done. JB works fine too. It is not a real big issue. You definately want to drill a hole and make if flush.

A little piece of brass channel stock will neatly hold the sensor. Hose clamp it in place.

Nikolas K

Thank you for the answers. I will try using J-B Weld. I didn t know it, but after having read its properties I think it is a very strong epoxy adhesive.
You will see photos of the conversion soon. I will have to experiment of course with the timing setting, compression and the gas-oil mix. Initially, I think that I will install one more head shim to reduce compression and I will use a 20:1 gas/oil mix...

gkamysz

My Feedback: (19)

There is no need to reduce compression ratio. Adding one extra 0.1mm shim will reduce compression ratio by 0.2. You won't notice this.

Nikolas K

It' s the first time I read this. Can you please explain?
The instructions state cearly to add one or two head shims in order to reduce the compression ratio of the engine- and it seems reasonable to me.

w8ye

My Feedback: (16)

The Saito gas engines have a higher compression ratio than the glow versions

gkamysz

My Feedback: (19)

Why would you need to reduce compression ratio? A stock ASP 52FS-AR has a CR of 7.8:1 Adding one 0.1mm gasket will reduce compression ratio to 7.6:1. What will that do? You could easily run the 52 at 10:1 without any problems.

Nikolas K

So, do you suggest that I run first the engine with the compression ratio as it is now and then decide? The static advance sould then be between 28-30 degrees?
And another question. I glued on the sensor holder to the hose clamp. Of course, adding the thickness of the clamp and the glue, the sensor will now be sitting quite higher against the magnet. Will I have a problem with sensing the rotating magnet?

Aussie Maddog

My Feedback: (16)

This is a sensor mount I did for a Super Tigre 2300. It is secured by two M3 grub screws and can be rotated to set your timing.
If you have a 4mm diameter magnet, a 5/32 drill bit makes for a nice fit. I always drill a pilot hole all the way through the hub, but drill the 5/32 to the correct depth. I use CA to glue. You can dimple both sides of the hub, next to the magnet for more security if you like.

Nikolas K

hmmm, drilling the hub will not be a problem, I think. I glued the sensor holder on the clamp. The sensor holder will have a 2mm clearance from the hub however. I have to check if the sensor will operate with such a gap. If not, I will have to figure out what to do. Most probably I will raise the magnet (i.e will not dill a deep hole).I will test before drilling.

w8ye

My Feedback: (16)

I have an engine with the sensor JB Welded inside a piece of K+S square tubing that is soldered to a worm clamp.

Jezmo

Jim, that's how all of my two stroke conversions are done with the exception of the JB weld. I prefer to use something easier to remove when the hall effect goes bad. This setup makes it very easy to adjust timing and even quite easy to make the hall holder itself. The hall effect holders on my four stroke conversions are a different story.

spaceworm

Please, how do YOU hold the Hall effect sensor in the tubing? And how are the FOUR stroke configurations different? TIA

Sincerely,

Richard

Nikolas K

I just finished the conversion. I think now that I have a small .52 cuin gasser!!!

The spark is being generated. The fact that I have a clamp will help me adjust timing while testing. Now I have to find a suitable test stand to fire it fr the first time. I am looking forward to it! I will try to upload photos or video on the Youtube.

Jezmo

I use Silicon to hold the Hall Effect and on the four strokers I use a piece of aluminum angle with a slot milled into the face to hold the Hall Effect. The angle is bolted to the cam carrier using one of the four screws that holds it to the engine case. The magnet is held by a 1/4" thick piece of delrin machined to slip over the prop drive and is held on with two grub screws. The grubs can be loosened and the delrin ring can be turned to adjust timing. The design comes courtesy of Bill and Terry of CH Ignitions. I have included a link to the thread where I discuss my conversion and the second picture in the first post shows the black delrin ring behind the spinner. You can also see one of the grub screws in the outer edge of the ring. The Hall Effect holder is also easily visible in the photo although the machined groove for the Hall Effect is not visible.

spaceworm

Thank you very much. I would like the additional detail, but the link did not show on your posting. Thanks again.

Sincerely,

Richard/SPACEWORM

Nikolas K

Well, behold my gasoline spark ignition engine, a modified glow ASP 52FS [8D]. Everything is ready. The only things remaining are to buy a 120ml fuel tank, synthetic two stroke motorcycle oil and two or three liters of unleaded gasoline. I will make an 18:1 fuel oil mix initially, because the engine is not broken in yet.
As gkamysz advised, I did not reduce the compression ratio. If knocking occurs, I will retard the spark timing. The adjustable clamp will make it easy.
Any comments?

jimmyjames213

My Feedback: (2)

hope it works, if it does i may try doing something similer.
let us know how everthing turns out

Jezmo

Sorry Richard, I don't know what happened but here's the link and a picture.

http://www.rcuniverse.com/forum/m_7282593/tm.htm

spaceworm

Got it now, thank you very much.

Sincerely,

Richard

Nikolas K

Hello Everyone![sm=teeth_smile.gif]

I bring back this topic, because I found time to run my ASP 52FS glow to gas conversion yesterday evening!
I have uploaded two videos on Youtube of the engine running and I would appreciate the insight and help from you in a couple of things.
First of all, the links for the videos are:

http://www.youtube.com/watch?v=v7Ja2pobF6o

http://www.youtube.com/watch?v=ZEsMiIpTjSs

I explain in the first video some things. I run unleaded 95RON gasoline mixed with 2-T Castrol oil at a 20:1 ratio. The compression of the engine was not reduced. Instead, I retard the advance, if I want, by rotating the Hall sensor on the hose clamp. The engine starts quite easily, after 3-4 flicks, provided that it is wll primed, almost flooded. The updraft carb, of course, plays its role for this.
The power and RPM level is not high, as you can probably see in the videos. First of all, the engine was not broken in previously. It was brand new and in the videos you can see its third and fourth run...so I run it rich (the big needle is opened 1.5 turn approx.). In the first video, where I close the big needle slightly, it increases RPMs. Anway, I have to run it rich because the engine is not broken in. And then comes the ignition timing adjustment for better performance, although I had to retard it while trying to start it for the first time, because it did not start easily. So, tuning is needed and I would appreciate your help.
I would also appreciate your help in the following two matters:
First of all, the engine has a lot of vibration, upto the point that I am araid for the integrity of the cylinder head where it connects with the muffler. The muffler vibrates a lot...Is it a characteristic of the converted engines? I also suspect the "test stand" I use...
Secondly, the exhaust emmits carbon particles, that get into the fuel tank through the pressure line. As you can see in the videos, the pressure line is black. After 4-5 runs,I noticed precipitated particles inside the fuel tank.I am worried thet they can get into the fuel feed line and block the carb orifice. It might be that I have incomplete combustion, due to the rich mixture, or is it the type of lubrication oil I use (which was cheap and I do not think is synthetic)?

bogbeagle

This won't please you.

I tried out one of these units, fairly extensively, over about 5 hours of running. The engine was an Enya .60 fs.

Try as I might, I was unable to get a satisfactory run.

The standard carb is impossible!

The best sparkie results were obtained with 10% oil and methanol, rather than petrol.




In a direct comparison with the same engine running on straight fuel ... and with a glow driver at the low end ... the petrol conversion fared very badly. Power, idle and reliability were all much better with the augmented glow.



I wrote up the results quite extensively, but no magazine would touch the work ... well, it might affect advertising revenue, mightn't it?

OTOH, I have heard people claim that these conversions work really well.

Perhaps I'm just a duffer.

HTH

gkamysz

My Feedback: (19)

I have an Enya 46-4C on spark that ran very well on methanol and E85. Airbleed carbs are easy. Two needle carbs intended for muffler pressure do not fair as well on gasoline due to the difference in air-fuel mixture requirement. I'm fighting an OS FSa-81 with this issue. you can tune the high end and the low end, but midrange will be rich. I might just put a Walbro carb on it.

Again, I don't know why there is any concern for compression ratio or ignition timing by converting this engine to spark. The stock compression ratio is WELL within acceptable range for gasoline. The engine probably will not knock even if compression ratio was DOUBLED! Timing should be standard 28°BTDC. The main needle will end up less than one turn open. 20:1 may not be enough oil, I was running 8% in E85 and was not happy with the results. Running an engine in at such light load will not seat the ring.

The excessively rich mixture and improper timing are the cause of carbon and vibration. Set it correctly! For break in you can mix fuel with extra oil and run several tanks.