how to insert piston into cylinder

[inspectorudy]

I had to replace the two rings on my Echo back pack blower and getting the piston back into the cylinder is a bear. The piston is still connected to the rod and I am trying to place the cylinder head over the piston and new rings. The piston is about 1 1/2 inches in diameter and I have tried using a hose clamp to compress the rings with no success because the adjustment area of the clamp hits the head before the ring can go in. . Any ideas without buying a ring compresser for one use?

[_DX3_]

Try a small straight slot screw driver. Get each ring started one at a time and use the screwdriver to push the ring into the groove and then into the cylinder. You have to work it a bit at a time, kind of like a tire bead. It's how I install most of my pistons.

[ol'George]

Originally Posted by inspectorudy

I had to replace the two rings on my Echo back pack blower and getting the piston back into the cylinder is a bear. The piston is still connected to the rod and I am trying to place the cylinder head over the piston and new rings. The piston is about 1 1/2 inches in diameter and I have tried using a hose clamp to compress the rings with no success because the adjustment area of the clamp hits the head before the ring can go in. . Any ideas without buying a ring compresser for one use?

First make sure the rings fit the cylinder without putting them on the piston.
Mistakes happen,seen it more than once.
You can make a nice ring compressor using a piece of sheet metal duct, stovepipe or tin can and a hose clamp around it.
I just use a screwdriver and/or my hands on something that small and only one cyl. to do.
Be careful you don't want to force it and break the rings.
Make sure the ring end gap aligns with the aligment pin in the piston ring groove if it is a 2 smoke engine

[inspectorudy]

Thanks guys for the info. It's funny you mentioned the little ring alignment posts because I had a hard time figuring out how I had burred the piston in such a strange place. Then I figured out that they were steel and the piston was aluminum so they were meant to be there. With the rod and lower engine attached it is a bear to work with. I got the piston back in but not attached to the rod and crank. I'll try the sheet metal first and then go to the one ring at a time screw driver method. That is what I did when I put it in without the rod attached. There must be an easy way that the factory does it. I thought about taking the wrist pin out and then putting the piston in just far enough to still put the pin back in but that is even a worse job than the rings. It has two of the worlds smallest snap rings that I have ever seen that go on each end of the pin.

[ol'George]

If you can get a helper to wiggle/rock and push down on the cyl. while you push the ring together with a screwdriver in either hand, it should go easy.
The "knock pins" as they are called, keep the ring end gap from working their way around the piston and into the ports where they would expand out and cause a diasterous outcome as you can well imagine.
Are you positioning the ring endgap properly on the "pins"?
The ring end gap has a radious for the pin, not just butting together,look closely it can only go one way correctly.
The "knock pin" in not centered in the piston ring land
It sounds like you are having way to hard of a time installing the piston into the cyl.

[green 4 acres]

my advise about 11am purchase a double cheeseburger meal and then head to your local independent motorcycle shop with the assembly and suggest a trade

[thenrie]

Just go down to Autozone and buy a ring compressor tool. They're cheap and it's the only way to do it without risking misaligning the rings and/or scratching your piston and cylinder wall. It is really a production model of what Ol'George was talking about, but made with precision spring steel, so you don't scratch anything. The thing doesn't run more than probably $10, but it's one of those things that when you need it you really wish you had one.

[Vince_o]

Kelly

Ring compressor is how I do them at work. The screw driver thing will work, but you know me, Ill scratch the piston or cylinder. If theres a way to screw something up, Ill find it!

[green 4 acres]

why did you have to replace the old rings? - from the picture it looks like you have light to medium scoring on the piston skirt, 2 cycles need a very smooth bore to work very long , 80-100 stokes per second , but then pretty cheap to try You really need the short pliers style ring compresser to install easily with new rings ( $ 40 and up) --- that why I suggested a cycle shop

[inspectorudy]

I like the bike shop trade idea. Here in Ga. I would need a six pack AND a cheeseburger! The reason I had to change the rings is that for the first time in over 40 years I put gas into the blower that was not mixed with oil. The engine ran fine for a while and then slowly went to idle and then off. I could not puill the chord and decided to remove the cylinder to see how bad it was. Once I got the piston out and rubbed down the walls with fine steel wool eveything worked smoothly with the old rings on the piston. Then I took it all apart to connect the rod to it and in the process of trying to get it back in I broke the rings (using the small screw driver method). I have ordered a new set of rings and will attempt it all again when they arrive. Does anyone know which way the rings need to face on the piston concerning the two little pins? The end of the rings are tapered in one direction and flat in the other. Looking at the two ends of the rings as they come together they form a "V" one way and an upside down "V" the other. It seems to me that the "V" should be facing upwards because the two pins are at the top of the ring groove. Any comments on this? Thanks everyone for you inputs.