balsa brain

I've posted here and asked a few questions and have got to the point of assembling my first conversion, a Ryobi 31cc. I have the piston with new Bowman rings in the cylinder and the cylinder is bolted to the crankcase, without a gasket or gasket maker at this point just to make sure everything works before I start finalizing it all. I also have the flywheel with the prop shaft adapter, some washers as needed and a APC prop mounted so I can turn it over. The plug I have installed is a Champion RDJ7Y, not the resistor type but that is coming tomorrow from the auto parts store.

I noticed that the rod had some slop where it connects to the piston before I put it in the jug. I have a couple more Ryobi pistons and checked them and they had the same slop so I assumed thats just the way they are. My problem or at least I think it is a problem is that when the crank pin and the bottom of the rod are at about the nine o'clock position looking from the back of the engine I am getting a clicking sound. I looked at the bearing after I soaked and cleaned all parts in gas and they appeared to my untrained eye to be okay. If it was at TDC I would check it with a gasket installed to see if the piston was maybe hitting the plug or the top of the cylinder. I ported the exhaust to 150 degrees and very slightly rounded off the top where the rings slide by. I really can't think of anything else to say about what I've done to this engine that might help anybody that may want to offer an opinion as to what is causing this clicking.

Before I close I would like to say thanks to everybody that has contributed to this conversion forum. I have been reading it for months and have finally got all the parts together in one pile to try and do a conversion. I designed and built the plane and have finally got to the the point where I need to install the engine after breaking it in with the new rings and tuning the carb, a new WT-391 that I got from an auction site.

Thanks in advance,

Bill

w8ye

My Feedback: (16)

You may have to go through the process of elimination to find the click

Pull the cylinder off and see if you still have the click or can at least feel it?

This will isolate the main bearings from the rod/piston - cylinder?

Due to the position of the click, it seems like it would be the ring going by a port?

balsa brain

I just went back out to my shop and put a cylinder/crankcase gasket in it and took out the plug. I was rocking it back and forth to see if the clicking sound was still there and it was but it seemed to be more in the or close to TDC. I have another two ring piston soaking in my gas jug and will try that later. I just hate to take those new rings on and off many times because I am afraid I will break one of them. Something i for got to mention earlier is that this is the Ryobi with the wide single intake journals. I have had four separate weed whackers that I have taken apart trying to get a good one and three of them are different.

Something that I did not say earlier and that I wanted to say was that a few months ago if somebody had asked me something about an intake journal, ring land, port timing and so on and so on, I would not have had a clue what they were talking about. It is only through reading all of the posts that you fine folks have posted that I can say that I feel a little more comfortable talking about these conversions. Changing the port timing was very intimidating even after i had made a degree wheel. I am a woodworker by trade and if these engines were made out of wood I could probably figure it out pretty soon. It is only after reading and reading the many posts you folks have made that made me feel like this was something i could do. I can't express how much I appreciate all the help.This has been a most enjoyable project from the beginning to I hope a successful ending.

Bill

Edited to correct sloppy two finger typing

w8ye

My Feedback: (16)

This first part of this post is for new people that may be reading this?

The gap in the ring must not go through a port area.

I'm sure you have already been there but the ring must be pinned to keep the gap between port areas
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If your catching or clicking point moved, it may very well be a bearing? I rebuild a lot of glow engines and old bearings are frustrating in that you will think you have them cleaned out and that they will be fine and the next time you pick the engine up, there is a rough place in a bearing.

balsa brain

Yeah I have got the rings in the right place on the pins. Frank said that I would have to recess the pin down half way so the rings would I guess key in place. On another post a while back when the end gaps of rings were being discussed someone posted that their stock Ryobi rings were very close to no ring gap and thats the way these were on my engine. The pins were already recessed down and Frank's went on the piston as it left the factory. I did however have a hacksaw blade with the notch filed in it as Frank said to knock the pin down, just didn't need it. I guess knock is a little to harsh of a word so let me say tap it down.

I went back out to my shop and changed the piston out with the one other that I had that was like the one I started with. I did it without breaking the rings, knock on wood. It seems to be better with not so much a clicking noise but rather mechanical. I am sorry but that is the only words that come to mind to describe it. I put the other crankcase in the gas and will clean and try that next. Thanks much for trying to help me w8ye, I appreciate it.

Bill

rangerfredbob

My Feedback: (13)

it sounds like you're learning a lot and are getting somewhere!

Good luck!

balsa brain

Kinda reminds me of trying to get a computer to act right, lol. I changed out the crankcase for the other one i have that is the same and am still getting some noise, but now it seems to be at the top and the bottom of the stroke. I feel no resistance at all to going through a complete 360 degree rotation so maybe I am over reacting a little. Or not I was thinking that maybe I had dried out the bearing by soaking em in gas and so I put a drop or two of two stroke oil on them and that seemed to help or maybe it was just masking the problem. I'm gonna keep messing with it but have few parts to keep eliminating things.

Bill

balsa brain

No actually I think I would be a good poster child for new.

adrian222

My Feedback: (1)

The clicking sound you hear is the ring or rings moving in there groove take the ring off and try it and see what happens.

Adrian.