Stihl 044 Cylinder&Piston madness

[atimen]

Hello everyone,
Can I ask for your advice or opinion regarding the combination of cylinder and piston that I have available?

In the photos with the cylinders, on the left is my original original cylinder from 044 (A) which I tried to fix by hand sanding after the piston seized, and on the right is a cylinder that was supposed to be from MS440 (B), I have a 044 12mm, it should fit. I bought it with the piston together for 60 usd. But I find that it will probably be from the 044 made in the early years because the piston has a hole for a 10mm pin. In the photo with the pistons On the left is my original from the saw (AB), in the middle is the piston purchased with the cylinder (AB) and on the right is the piston that I bought some time ago in a set as a replacement for my destroyed one for 20 usd (BE).
In addition to the fact that the purchased cylinder also has a decompression valve and a different thread diameter for the spark plug, can it be used with the piston I bought some time ago? (On the right in the photo)

Alternatively, can someone please determine for which saw the cylinder on the right and the piston in the middle are intended?
The seller offers me a refund.

I don't know if I got an unused original cylinder with a piston for 044 10mm, which would cost a lot more, but it would be unusable for me.

Thanks for any advice.

View attachment IMG_2266.JPG

View attachment IMG_2267.JPG

 

[altatim]

If I am correct the 10mm and 12mm cylinders are more or less the same but the piston/conrod are different. I think you can just go buy a meteor piston kit for it and use the early style cylinder without any issues. Both should be 50mm bore. From your photos it looks like the right cylinder is from an MS440 and they just happened to ship it with a 10mm piston.

 

[pioneerguy600]

There is only one small problem with swapping these cylinders and that is the ring ends of a 12 mm pin piston can catch in the intake port of a 10 mm cylinder, or lets just say the angled top fin cylinders as all 10 mm pin pistons were in angled fin cylinders. The ring keeper pins in the 12 mm pistons were moved in toward each other just a smidge so it is possible the ring ends could end up crossing over the intake port. This does not happen on every cylinder but one should check visually to make certain the ring ends do not cross over the open port, if they stay supported by the cylinder walls there is no problem running the 12 m piston in a angled fin cylinder.

 

[huskydave]

There is only one small problem with swapping these cylinders and that is the ring ends of a 12 mm pin piston can catch in the intake port of a 10 mm cylinder, or lets just say the angled top fin cylinders as all 10 mm pin pistons were in angled fin cylinders. The ring keeper pins in the 12 mm pistons were moved in toward each other just a smidge so it is possible the ring ends could end up crossing over the intake port. This does not happen on every cylinder but one should check visually to make certain the ring ends do not cross over the open port, if they stay supported by the cylinder walls there is no problem running the 12 m piston in a angled fin cylinder.

Yes, the ring pin is timed different on the 12mm piston.

 

[atimen]

Thank you for the observations, I will return the cylinder with the piston to the seller.
I will still find out the possibility of buying a new original cylinder, or I will try to use a repaired original cylinder with a new piston, the last option would be to buy a meteor set.

 

[Mad Professor]

There is only one small problem with swapping these cylinders and that is the ring ends of a 12 mm pin piston can catch in the intake port of a 10 mm cylinder, or lets just say the angled top fin cylinders as all 10 mm pin pistons were in angled fin cylinders. The ring keeper pins in the 12 mm pistons were moved in toward each other just a smidge so it is possible the ring ends could end up crossing over the intake port. This does not happen on every cylinder but one should check visually to make certain the ring ends do not cross over the open port, if they stay supported by the cylinder walls there is no problem running the 12 m piston in a angled fin cylinder.

An awsome warning for mix and match 044/440 stuff

 

[pioneerguy600]

An awsome warning for mix and match 044/440 stuff

As long as everyone understands yes, a 12 mm piston can be run in the 10mm cylinders if the ring ends are far enough away from the intake port, I have 2 out of the ten I have that are doing fine but I measured first and found there was sufficient cylinder wall support for them, they are about.040 away from the port opening on one side and .060 on the opposite side. Some 044`s came from the factory with 12 mm pistons in 10 mm angled fin cylinders made shortly after the changeover to the 12 mm piston pin . General consensus is that Stihl used up whatever leftover stock they had on hand. I have messed with the 044 and MS440 saws quite a bit and have some strange birds like a 10mm crankcase with a 12 mm crank I swapped in just because I wanted to and a couple 044`s with 046 cylinders often referred to as hybrids. Today I was involved with cleaning up 044 parts, several boxes I had hoarded up that needed some serious cleaning, possibility of a couple more 044`s joining the others in the near future.