Echo 16cc conversion results
 

I've always wanted a smaller converted engine, so I just finished doing one. The engine is an Echo 16cc that was originally made to run clockwise. Lefthand threads at the flywheel end were of little concern to me. I made an adapter for the 5/16" shaft and just recessed the nut below the adapter's mating face. Made the prop adapter to bolt onto it with 2 recessed 10-24 thread allen head capscrews. Worked out perfectly and very true running. Installed a new factory ring and converted the engine to CDI.

Performance is improving as the ring starts to break in. I am using a MAS 13-6 plastic prop that was carefully balanced. On the second 8 ounce tank of 32:1 Pennzoil and regular gas, I took some rpm readings with an Ace Optical tach and got a reliable 1600 rpm idle, followed by 7200 rpm top end. I am thinking it could gain maybe 500 rpm after some more running. Is 7200 a good starting figure for this lightweight engine?

Made a muffler for it from 1 inch square aluminum tube about 3 inches long, with a single exit stinger from 1/2" aluminum tubing. Inside the muffler, I drilled about 8 or so 1/8" holes to pass the exhaust thru. Drilled a hole in the side of the muffler for a retaining screw into the tubing locking it in place. I cut 2 end caps for the muffler from 1/4" 5 ply aircraft plywood. Retaing those in the ends with small sheet metal screws. After almost an hour's running time, it's still together and no noticeable leaks and is very quiet.

Pictures are in order when I get time. Using a C&H ignition with one of my autoadvance boards to give it a fighting chance. Hand starts in 2 or 3 flips. Can't ask for much more than that, and total cost was just for my time and a factory new ring. A Bowman ring will make it perfect.

John

RE: Echo 16cc conversion results
 

I can't remember the rpm figures for the Echo 16cc I did, but it was my first gas conversion. It flew my 11 lb. Ugly Stik fairly well at sea level, but when I later moved to an elevation of 4000', (with hot weather too!), performance was less than stellar. It would be great on a "floater" like a Cub or Telemaster though.

I have a McCulloch 22cc which is about the same weight as the Echo 16cc for sale if anyone is interested. It is all converted, and ready to fly on either Gas/Glow or regular gas ignition. Just PM me...

AV8TOR

RE: Echo 16cc conversion results
 

I haven't had the chance to open the case yet, but I am hearing alot of clicking when I flip the prop. What type of bearings are on the crank? Can they be replaced easily? I didn't notice the clicking before I replaced the ring, but I doubt it is play in the ring groove on the piston. Probably the con rod lower end from reversing running rotation would be my guess. I want to put it on a Nosen Citabria if it holds up. I have a twin with the same cylinders but they don't share a common crankcase. Twin carbs are Wa-46 Walbros....really small Venturi. Still have one more Echo hedge trimmer 16cc to convert, but that one runs the right direction. So many engines, so little time.

John

RE: Echo 16cc conversion results
 

The one I had was ball bearing. I don't think Echo used any roller crank bearings. (If they did, it was probably on an older chain saw, though I doubt it even then.) I am quite positive they never used a bushed bearing rod...

AV8TOR

RE: Echo 16cc conversion results
 

This weekend I want to see what the clicking is. Flipping the prop thru compression last night yielded something strange. When it is clicking, there is little to no compression. If I turn it backwards a few turns slowly, then turn in the direction it now runs, it becomes quiet and the compression returns. Really odd behavior. I am at a loss to explain it but maybe after I open it up, I'll see something wrong. When I changed the ring, the piston looked practically like new, but it had next to no compression so I changed the ring. I have another good case with good crank and quiet bearings but a scored cylinder and piston. Might try transferring my good parts to that one in the odd chance I'll end up with a perfect engine.

Is it possible that the crank pin for the rod has loosened, causing the click I am hearing? If that is the problem, that crankshaft is not useable. Maybe I should just take it apart and see what's going on.

John

RE: Echo 16cc conversion results
 

They will often make a clicking sound as the crank goes over top dead center and any clearances are "taken up" and reversed. It is probably ok, but hey, they are so easy to take apart I recommend doing so to be sure all is well. Having had reversed the rotation should make no difference nor harm.

When swapping pistons, be sure that you verify that the ring can't get caught in the exhaust port. There is usually an arrow on the piston that should point towards the exhaust port. I might still have my 16cc piston and cylinder here if you ever need a spare.

AV8TOR

RE: Echo 16cc conversion results
 

Now that I have the case opened, I found what is causing the noise. When I changed the ring, I also installed the back half of the prop adapter. In the process of tightening the left hand nut which is locking it to the crank, I gripped the opposite end of the crank with a visegrip to hold it from turning. Somehow while tightening the nut, the crankpin broke loose from it's press fit in the two crankshaft halves and now looks crooked. If I rotate it backwards, it straightens out and there is play. Then rotating it in the new running direction, it shifts and there is no play. I'm thinking there is no easy way to secure it other than setting it into a pair of v-blocks and welding it in the aligned position. Other than that option, the crank is now unusable. What a shame since the engine came out perfect otherwise. I could live with the click if it was just normal play, but as it is, this is going to wear the rod big end bearing.
Never expected to see this problem in a small engine. I now know I caused it and should have gripped the same end the adapter is mounted to. Maybe replacing the crank is the best option I have?

John

RE: Echo 16cc conversion results
 

Yep, I would say the crank is junk. I know the engine is cute, but I wouldn't put too much effort into it. (Do a search here in the forum for Echo 16cc.)

The Echo 21 and 24cc engines weigh only a few ounces more but make tons more power. I have some for sale, both converted ready to fly, and not converted yet. PM me if interested.

AV8TOR

RE: Echo 16cc conversion results
 

I indicated the problem bad crank till I got it all but dead true. Tack welded one end of the crankpin for the rod so little chance of warpage from heat. The other end was still tight but just in case of movement later, I put one small tack weld on that end also.

In the process of all this, I inspected the bearings and one of them has a chipped ball bearing. Are these a standard size between all of the Echo small engines? I'd like to replace both ends since I have them off. I asked all my local dealers but they don't stock them cause they never go that deep into repairs. Isn't that what a dealer/service shop was supposed to do?
Oh well, I'll have to get a magnifying glass out to read the numbers though.
Anybody have the numbers already to save me the agony?

Thanks

John

RE: Echo 16cc conversion results
 

Go to www.bocabearing.com and they will have one for sure. All you need is an accurate inside, outside, and width measurement. No need to buy anything special, their standard or economy bearings are of very good quality for our uses.

You should be able to put a fairly good weld on that pin. I don't think enough heat will penetrate all the way through to damage the pin or rod bearing. Wrap the center section in a wet cloth.

The repair shops charge around 90 dollars per hour, plus the parts are very, very expensive. If they fixed an engine, the cost would be more than buying a new machine in almost all cases. Plus we had a saying back when I had mechanic shops; "Once you touch a machine, (car, boat, airplane to weedwacker), you owned it." What we meant by that was from that day forward, if anything went wrong with the machine, it was assumed to be "your fault" and you were supposed to fix it for free.

AV8TOR

RE: Echo 16cc conversion results
 

Now that I have fixed the crankpin and found the chipped ball in the front bearing, I removed the bad bearing from the case. I had another case with good bearings that was unconverted, so I pulled one of those bearings and replaced my bad one. I reassembled the case, sealing it up with Yamabond (permatex ultimate grey sealer) and now the engine runs like new without any clicking and great compression.

I have a H9 80" cub I will put it on. The Nosen Citabria would have been too heavy for it at 14 lbs.
The ignition, battery, and home made muffler only added about 4 ounces to the total weight brining it to 2.5 lbs ready to run. Using the original WA-46 small bore carb. Tried larger carbs but they only made it run rich at top end and no improvement. This was a very rewarding project to say the least!

John