Volfy

My Feedback: (23)

Since I had my old Ryobi 31cc apart to install a Frank Bowman ring, I decided to try it with the WT-499 Walbro carb from my G23 glow I had lying around.

Wow! Was I surprised. Even with the needles set very rich and the Bowman square ring not yet seated, the Ryobi was turning the 16x10 MA 8200rpm effortlessly on 15% nitro 18% oil. I momentarily pinched the fuel tubing and saw it blipped up in the high 8k range. I didn't dare run it steady near 9k, both while breaking in the new ring and with that darn stamped steel conrod. I have no doubt once it's broken in and I run it on a lot less (5%) oil, it will spin an 18x8 at the mid 8k rpm range. My guess is that it'll fly best with a 20in prop.

I can't wait to try this combination on the new twin-ring Ryobi 31cc I just bought. I hope Frank Bowman makes square rings for the new one, because I'm gonna get 'em! The twin rings look to be thinner than the single ring 31cc.

Okay, somebody is going to ask, so here it is:

bare engine w/ carb: just a little over 2lbs.
RTF as shown w/ B&B muffler and engine mount: 3lbs.

The overall cost is probably less than $125. Now why on earth would I want to pay twice that for a 160FX or a Moki?

Volfy

My Feedback: (23)

Here's a look at the overall setup with my trusty teststand.

bn120

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you need to try 0 nitro and 5% oil and see what you have.

Darin

Volfy

My Feedback: (23)

Yap. Got 2 gals of 5% castor FAI fuel ready to try. I wanted to use plenty of oil but not too much for seating in the new rings, so I grabbed the 18%.

I will run it again next weekend on FAI fuel and post the RPM here.

ngr1

My Feedback: (2)

Hi Volfy, can you please provide the steps required to convert a Ryobi to glow operation.

Can the stock carb be used in a glow configuration? If not what would you recommend?

Which glow plug did you use and how was it installed?

Any help would be appreciated.

Thanks

Norman

captinjohn

ngr1: You might be able to break the center out of a spark plug that threads into the Ryobi. Tap threads into where porcelain was .....then ou have a plug adapter. Also check with RCIGN he has done this trick also. I have a Homelite I am going to try when it warms up. Good luck Captinjohn

tkg

My Feedback: (1)

CH Electronics has them in stock, just ask for the 1/4x32 to 14mm adapter. They also have 10mm to 14mm and 1/4x32 to 10mm too.
P.S. The prop hub that is in the pictures is available separate from a full CH conversion too

Volfy

My Feedback: (23)

Norman,

The steps are the similar to a gas conversion, except much simpler. Basically, you just strip the Ryobi down to bare engine block, put the glow adapter, prop hub, and new carb on it - that's it. I did retap the drive shaft tip internal thread from 8-32 to 10-32 so I can put a 3" GP spinner on it.

There are many websites detailing the exact steps, so I won't repeat them. Here is a good one:

http://www.geocities.com/CapeCanaveral/Lab/6216/

The glow plug adapter came from my G23 glow. I'm also getting another one from CH Ignitions. OR, you can make your own. For the initial bench run, I just use the cheap old Tower economy plug w/ idle bar. Once the engine is broken in good, I then experiment with other plugs. As is typical, the Tower plug runs great as is.

I guess you can try the Ryobi stock carb. It has a very restrictive venturi though, so even if the needles can be opend up enough to meter glow fuel, it might not flow enough air to make good power. I have a bunch of these small venturi carbs from all the weedie conversions I've done, some of which are fixed jet and therefore useless for RC application. Instead of trying to modify them, I just strip out the diaphram pump section and use it like a Cline pump/regulator. Replacement big bore carbs cost around $35 for these weedies.

SuperJ

I find I really like a compromise setup using ignition and E85 with 4% oil, half Torco synthetic and half Klotz beNOL. E85 is cheaper than unleaded now and in corn country you can buy as much or as little as you want right out of the pump. It runs within 2% of a methanol FAI glow conversion with better transition, and a substantial savings in costs.

Volfy

My Feedback: (23)

SuperJ, Hiperfuels is local here in Houston, so I can get E85. It's rather pricy compared to both straight pump gas and methanol though, so I doubt it will be any more economical for me. Ethanol does have a higher stochiometric ratio than methanol, so gas carbs will probably work better with it.

I do have a CH Ignition kit for the Ryobi, but I really like the simplicity of the glow system on this motor.

SuperJ

I drove by a CENEX station on my way to work this morning unleaded $1.66 E85 $1.18. Man if I owned a flex fuel vehicle I know what I'd be running on right now!

Volfy

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Hmm... I need to find a local gas station here that pump E85.

SuperJ

Go here to see if you have any local refueling locations. I am not sure how up to date their information is though because two of the three locations I buy it at aren't on there.

Volfy

My Feedback: (23)

Thanks for the pointer, SuperJ. You guys are lucky there in corn country. TX has no pump stations for E85. It does show Hiperfuels as a source though, but even deducting the $20 HAZMAT fee, it's till mighty expensive at $70 + tax for 5 gals. Methanol is only $22/5gal for me.

I think I'll stick with straight methanol, 5% oil and maybe a little bit of nitro to help with transition.

BTW, I just got a reply from Frank Bowman. He does have rings for the dual ring Ryobi 31cc - that should give even better compression seal.

napierm

Out of curiosity:

Does the new 2-ringed Ryobi still have those "slits" in the cylinder wall above the intake ports?

Anyone know what those slits are supposed to be for?

Has anyone checked the new engines to see if they make any more power?

Anyone found a better source for a core engine than a refurb trimmer from Harbor Freight? That's where mine came from. It just seemed like such a shame to throw all that stuff out.

Thanks in advance,

Mark Napier

CrazyHerb-RCU-delete

My Feedback: (2)

Idea....

Just put the parts up on Ebay!
hehehe...

If you sell them for say....10 bux you can take that off what you paid for the thing to begin with....so a $60 weed trimmer becomes a $50 trimmer....

I'm sure there's some small engine shops that will take it.
CrazyHerb

Volfy

My Feedback: (23)

Mark, yes the new twin ring version also have the "vertical" slits. I don't know what they are for. Seems to me that they will bleed off compression early on the power stroke, but that would be a bad thing. I'll take a picture and post here. Maybe somebody else knows what they're for.

Volfy

My Feedback: (23)

Captinjohn, the Ryobi runs great on glow fuel. Even with all that oil, and with the needles set unecessarily rich, it transitions very well. I think it will run even better when I drop the oil percentage to 5%. I don't think it needs 15% nitro either. I will try 0% first this weekend, but will probably end up mixing in a little nitro (<5%) for better overall performance.

I can't say enough about those Frank Bowman rings. I remember running the stock Ryobi on gasoline and CH ignition back when I first bought it. IIRC, I was getting around 7000rpm with an 18x8, maybe a little more. Swapping in the Bowman Ring got me some 500rpm gain almost instantly.

I start the Ryobi with my Tower HD starter. It had trouble turning it over on 12V initially, but started up no problem on 24V. I don't like hand flipping glow engines, so I don't know if this one bites or not. It's fairly low compression ratio engine (7:1?) so I doubt it does.

captinjohn

My guess it is some kind of compression release. May not hurt much when up to speed???? Seems like Homelite had a small hole to release compression???? Capt.n

Volfy

My Feedback: (23)

BTW, with the exception of the twin ring, I bought my other Ryobis at Harborfreight. They had a sale in one of their flyers for $49.95, soI bought two. I doubt you can find a bare engine block, reman'd or not, for less than that.

Try pawning off the rest of the weedwacker, chainsaw, etc. at your local service shop. Do try to get cash. Instead, barter for carbs, seal kits, and maybe other engines. Even giving the stuff away free is a not a bad idea, if it let you cozy up with the shop.

Flypaper 2

Captinjohn:
Decompressor on the Homelite was actuated with a starting trigger lock,but it dropped the comp so low you had to crank really fast to get it to start. Not good for a little f##t like me! Oh well, I guess their intentions were good.

GKraemer

Volfy,

I'm interested in converting a Ryobi to glow. I see you used a WT 499 carb from a 23cc Zenoah. Do you have any idea how I can find the Walbro number of a carb designed for glow (methanol) for an engine int he 35-41cc range. I would think the 499's venturi would be a bit small for the 31cc ryobi.

Thanks

Garry

Antique

My Feedback: (4)

Walbro makes no glow carbs, some, lke the WT499, just happen to work with no mods.....It's plenty big enough for a 41cc....a larger carb usually makes no difference, unless the original was intentionally too small.....I put a 499 on a G26, ran gas,turned 9000 rpm...Unplugged the gas tank, plugged in the glow fuel, and turned 9600 rpm......Had to re set the needles for glow, otherwise no difference in function......Used spark ignition for both tests....a glow 26 weighs less than 2 lbs, is not yet sold by Horizon...A WT499 is about $40.00 retail......

captinjohn

Garry: Just make a adapter and use a carb off a big glow engine. May need a perry pump or pressure from muffler to fuel tank. Capt,n

CrazyHerb-RCU-delete

My Feedback: (2)

Volfy,
Did you ever get a pic of the vertical slits on the cylinder?
Curious, I'm about to tear down a twin-ring...

CrazyHerb