034 pistons open or closed window/ based on open or closed port cylinder

[Cracker Boy]

Today i ordered a meteor piston my vendor asked if i wanted a windowed or non windowed piston. I said didnt know there was an option. He asked is old piston windowed or non windowed and that its determined by the ports being open or closed. I said well im putting an open port 46 mm cylinder on it he said that the closed window would be best. I do know stihl only calls for one piston wich is open windows. Any thoughts comments pics or would greatly appreciated. When he told me this the little wheels started to spin. Now id like to try this piston on both open ports and closed ports on same saw rim bar and chain and do a test.

 

[Stihlsmoking]

Interested in this also as I have 034 I'm building an have open and closed port cylinders but my piston is open window ? Wonder which would be better to build ?

 

[Motorhead]

Interested in this also as I have 034 I'm building an have open and closed port cylinders but my piston is open window ? Wonder which would be better to build ?

pictures?

 

[Deets066]

Closed window piston would probly close off the transfers too much on the closed port cylinder.

There could be an advantage but it would have to be fit up and checked out

 

[Stihlsmoking]

pictures?

I only have open window piston ?

Open port
Closed port.

 

[Cracker Boy]

Closed window piston would probly close off the transfers too much on the closed port cylinder.

There could be an advantage but it would have to be fit up and checked out

Honestly wouldnt know how to fit up and check. Any suggestions here is pic of the meteor 46 mm closed window piston.

 

[Stihlsmoking]

Open window piston.

 

[Cracker Boy]

It has alot of support all the way around to me for the open port cylinder.im kinda looking forward the build.not much room for piston skirt wear.

 

[Deets066]

Honestly wouldnt know how to fit up and check. Any suggestionsView attachment 102160 here is pic of the meteor 46 mm closed window piston.

Just have to find BDC and mark the cylinder, then pull the jug and piston, align the mark and see what it be lookin like

 

[Motorhead]

I only have open window piston ?
View attachment 102152
Open portView attachment 102153
Closed port.

That’s the right piston for those cylinders

 

[Cracker Boy]

I only have open window piston ?
View attachment 102152
Open portView attachment 102153
Closed port.

Thanx for pics of jermey.

 

[Cracker Boy]

That’s the right piston for those cylinders

If so why does meteor offer open and closed port pistons for the 46 mm stihl. 034 please explain the reason. This is why i created the thread thanx.

 

[Stihlsmoking]

Honestly wouldnt know how to fit up and check. Any suggestionsView attachment 102160 here is pic of the meteor 46 mm closed window piston.

That piston looks better for a open port ? Like you said has upper and lower support!!

 

[Deets066]

That piston looks better for a open port ? Like you said has upper and lower support!!

Probly would help with velocity in the open port since the piston has more mass

 

[Cracker Boy]

Just have to find BDC and mark the cylinder, then pull the jug and piston, align the mark and see what it be lookin like

How do you mark it?thru the exhaust?

 

[Deets066]

How do you mark it?thru the exhaust?

Yup, sharpie works

 

[Stihlsmoking]

Just have to find BDC and mark the cylinder, then pull the jug and piston, align the mark and see what it be lookin like

I gotta get me a timing wheel and do some more learning.

 

[Motorhead]

That piston looks better for a open port ? Like you said has upper and lower support!!

If you look at the bottom of the transfer ports they are closed off from the crank case a sold piston would not create good flow.unless the piston you Have is narrower at the bottom,If it is narrower at the bottom go for it.

 

[Cracker Boy]

I gotta get me a timing wheel and do some more learning.

Wish someone could teach me more about timing wheels

 

[Cracker Boy]

Yup, sharpie works

I figured do to exhaust being higher.never got into it that much till now.ive allways let you porters do your magic thanx deets