Jonsered Chainsaws

[Hoggwood]

Looking at the IPL, I figured that the piston for the 630 changed to this style (single ring) in the later models? I thought these were both windowed style pistons and could be used in the closed port cylinder 630. It came out of a 61 open port, so now I am plain confused. Open/closed/windowed/non-windowed - I haven't been doing this stuff long enough yet. If I could use either, I was wondering what would be the better option.

 

[Cantdog]

Looking at the IPL, I figured that the piston for the 630 changed to this style (single ring) in the later models? I thought these were both windowed style pistons and could be used in the closed port cylinder 630. It came out of a 61 open port, so now I am plain confused. Open/closed/windowed/non-windowed - I haven't been doing this stuff long enough yet. If I could use either, I was wondering what would be the better option.View attachment 480949

Ok.....I'll try to explain a little clearer.......first your 630 piston, with the two thin rings is a windowed piston. And yes Jonsered changed to a single ring piston later.....but still a windowed piston....not like the 61 piston shown. The 4 holes in the piston sides surrounding the wristpin ends are "windows" and were designed to be run with a closed port cyl.......closed port meaning that the transfer ports that direct the fuel mix from the crankcase to the combustion chamber consist of the lower transfers and the upper transfers which are connected by a tunnel that isolates the fuel charge from the downward moving piston. As the piston moves down there is a very small space of time when these ports are closed not giving the fuel any place to go....crankcase pressure increases as the piston continues down until the windows in the piston enter the lower transfer ports....the fuel charge is routed up and around the wristpin bearing and inside of the piston crown before exiting through the windows in the piston and out into the lower transfer ports and is discharged out of the upper transfer ports to expel the burned gases and provide the engine with the fresh charge. The advantages are; increased velocity in the charge, a better lubricated wristpin bearing and a much cooler piston crown...all of which simply make a more powerful engine.

Open ports cyls have transfer ports that run directly from the crankcase to where they terminate at the top and are open to the piston all the way....a much simpler design and looks to be more efficient from the reduced restrictions.....however this is not case in operation. Open port motors work fine...the 61 Husky and the 49SP Jonsereds are a fine testament to that but they are not as powerful nor take as much abuse as...say the 52/52E for Jonsereds and 266XP for the Husky.

It is possible to run a windowed piston(630) in an open port cyl (61) with OK results...however a closed port cyl (630) will not run well at all with a non windowed piston...(61)

What I was saying earlier was that though your 630 piston looks to be in very good condition it has the thin rings which you cannot buy/replace. These were considered a very high performance piston/ring combinations but were only made and used for a short time due to the fact the thinner tings had much less tension than the thicker rings and were prone to sticking in the ring grooves if exact oil and fuel ratios were not adhered meticulously. So unless your rings are in near perfect condition and you understand how to operate a saw with thin rings I would replace the piston with a new windowed piston....these can be had with either 1 or 2 standard thickness rings.......but you won't like it if you try to put your 61 piston in your 630 cyl. Now if power is not your concern you can put the 61 P&C on your 630 saw and it will run fine........with 61 performance....not 630 performance....

In closing.....it all comes down to money...open port P&C sets are simpler and cheaper to produce at the factory level......they work fine but dot not produce the power output of their closed port kin. The difference between Semi Pro saw and a pro saw........think...350 Chevy pickup truck motor......then think 350 Chevy Corvette motor........same size motor......one simply breathes better than the other........Hope this was helpful....

 

[Hoggwood]

Thank for the response Robin. I appreciate the detail.

 

[fossil]

Cory,

If you're concerned about using the 630 two ring piston, Episan makes a two ring windowed piston kit. I put one in my 630 and it works great. The Episan SKU # is 1185.

Episan has a good reputation.

 

[Hoggwood]

Thanks Tim.

I had checked DLA a bit a go looking for a Meteor. I didn't pull the trigger. The picks for the 625 and 630 pistons had/have me puzzled. I am thinking pics for the 625 should be for the 630 and vice versa?

625: http://www.dlastore.com/e_store/eng.../piston-kit-fit-jonsered-625-625-ii-48mm.html

630: http://www.dlastore.com/e_store/piston-kit-fit-jonsered-630-630-super-ii-48mm.html

Where did you pick up your Episan?

 

[fossil]

Thanks Tim.

I had checked DLA a bit a go looking for a Meteor. I didn't pull the trigger. The picks for the 625 and 630 pistons had/have me puzzled. I am thinking pics for the 625 should be for the 630 and vice versa?

625: http://www.dlastore.com/e_store/eng.../piston-kit-fit-jonsered-625-625-ii-48mm.html

630: http://www.dlastore.com/e_store/piston-kit-fit-jonsered-630-630-super-ii-48mm.html

Where did you pick up your Episan?

I know they list both open and closed pistons for the 630. I am guessing they made open port cylinder model as well. Best ask Robin or Eric.

I ordered it from Northwood saw. That's the only place I found it. $30 US. Their shipping is reasonable.
http://northwoodsaw.com/store/index.php?l=product_detail&p=775

 

[MnSam]

I picked this up yesterday. It needs a little attention but is in great condition. I'm not sure if I want to fix or sell ...

 

[dakotan2]

I picked this up yesterday. It needs a little attention but is in great condition. I'm not sure if I want to fix or sell ...

Looks great!

 

[taplinhill]

I know they list both open and closed pistons for the 630. I am guessing they made open port cylinder model as well. Best ask Robin or Eric.

I ordered it from Northwood saw. That's the only place I found it. $30 US. Their shipping is reasonable.
http://northwoodsaw.com/store/index.php?l=product_detail&p=775

The 630 was closed port cylinder/windowed piston. The 625 was the open port cylinder/ non-windowed piston. Both were the same 61.5cc.

 

[taplinhill]

Looks great!

I agree, it's a looker (And if I had it, a keeper!).

 

[Hoggwood]

I'll have to go after another piston. End gap is very large.

How about this one? http://www.dlastore.com/e_store/eng.../piston-kit-fit-jonsered-625-625-ii-48mm.html.

Most affordable to my door.

 

[fossil]

You might e-mail him to make sure the pic is correct and it is a windowed piston.

 

[Cantdog]

You might e-mail him to make sure the pic is correct and it is a windowed piston.

I agree......you want the one in the pic......I have bought from him...good seller though it takes a bit longer to here from Greece....

 

[Cantdog]

I picked this up yesterday. It needs a little attention but is in great condition. I'm not sure if I want to fix or sell ...

Yep...that is a great looking, low hour saw....worth more to have than sell.....

 

[fossil]

I agree......you want the one in the pic......I have bought from him...good seller though it takes a bit longer to here from Greece....

Interestingly, his stuff gets to Canada faster than parts do from the US. Likely something to do with customs at the post office on this side.

 

[WoodDean]

Probably won't have a problem with the wrist pin bearing....the wrist pin though, that's a whole 'nother kettle of fish.

J'red used some kinda gas tank coating in their older saws....which are peeling and dysfunctional now. I thought at first it was some kinda sealing tank repair, but I'm seeing it all through my older saws. You can split the case and get it all out, or BB & lacquer thinner the mess outa there.

Kevin

I actually have the wrist pin, just missing the bearing.

Speaking of gas tank coating, I just split the case on this 49.

 

[WoodDean]

And the other half;

 

[WoodDean]

I thought I had a 49 gasket but after I placed it on the case half it's missing a case hole in the gas tank. The gasket fits everywhere else although it doesn't completely cover the handle area.
I'm guessing it belongs in the family of 52, 521. Can someone ID the gasket from the pic?

?

 

[Cantdog]

That's the correct gasket Dean....all the same part #...49sp, 52/52E, 521..don't know exactly why they left that hole out...perhaps because it is so close to the others

 

[WoodDean]

That's the correct gasket Dean....all the same part #...49sp, 52/52E, 521..don't know exactly why they left that hole out...perhaps because it is so close to the others

Big THANKS Robin, always appreciate your input and knowledge.