Fitting a Husqvarna 246 Piston to a Stihl 026

[drf256]

Great stuff guys.

I'd like a piston with higher compression height.

 

[czar800]

A lot of Metallurgy involved. A lot of machining too. Aluminum is hardened before use. Welding makes it soft again.

I thought about building up the entire crown. That may work.

You forgot more about welding and metallurgy then I'll ever know!
In my limited understanding it seems like Welding would be best. Hear's a link to a discussion about welding on Pistons you may find interesting.

I first started reading not paying attention that Timberwolf was the OP.

http://weldingweb.com/showthread.php?23901-Welding-Aluminium-Pistons

 

[paragonbuilder]

The other 44mm piston of note is the Dolmar 111

The Meteor catalogue lists them as having identical specs so I wonder why they list them as different pistons?

View attachment 17682

View attachment 17683

Curious!

Looks like the 111 piston is flat, 026 is domed.

 

[Brewz]

Looks like the 111 piston is flat, 026 is domed.

Well that would save the step of machining the top of the 026 piston and would give better crown thickness for strength.

 

[Brewz]

Looking at it, the Dolmar 111 piston, if it does actually have a flat top, is looking like a good starting point for a basic flat top machine job

 

[czar800]

Could be worth a phone call for more information?


http://www.wiseco.com/ProductDetail.aspx?ItemID=648M04400&ModelID=242&ModelYear=1985&AppID=3121

 

[paragonbuilder]

Looking at it, the Dolmar 111 piston, if it does actually have a flat top, is looking like a good starting point for a basic flat top machine job

Be interesting to see piston pin to crown height. I may have a 111 in my pile of saws and parts I got a few weeks ago. I'll go take a look...

 

[paragonbuilder]

Nope... But I have a 540. Anyone know what the piston diameter is on a 540?


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[Brewz]

54cc... will be a bit bigger I think
Single ring though

 

[paragonbuilder]

54cc... will be a bit bigger I think
Single ring though

You are correct. I popped the top and its 44.8mm and single ring

 

[drf256]

You are correct. I popped the top and its 44.8mm and single ring

How big is the Pin?

Could be turned down to 44.7?

 

[paragonbuilder]

I'm out plowing at the moment I'll check when I get back. I thought you guys were looking for 44 mm?


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[Brewz]

Yes but 44.7 will fit an ms260 jug

 

[Chainsaw Jim]

The pre epa Husqvarna 350 flat top piston has a longer skirt with the same pin to crown height. It's like 3 or 4mm longer.
You'll have to get one with the flatter sides so you can cut windows.

Or just remove the bottom ring on your 026 piston and that will increase performance.

 

[ABarrick]

028 piston doesnt look promising either. It is taller and longer but the skirts are narrow also. It is a fair amount heavier too.

 

[ABarrick]

Could be worth a phone call for more information?


http://www.wiseco.com/ProductDetail.aspx?ItemID=648M04400&ModelID=242&ModelYear=1985&AppID=3121

Pretty sure that will use a bigger wrist pin. Wouldn't bet my life on it but I recall them being larger than a saw by a good margin.

 

[fearofpavement]

This is an interesting thread. The 026 is my favorite saw of them all. But all mine I run completely stock. Never felt they needed anything. Maybe I don't know what I'm missing?

 

[ABarrick]

Piston pics for alls amusement.

Left to right:
031,028,026,246,350,50,ms270,echo something lol

That's the lineup in the group pics, I moved them around for the sideby side closer shots. If you can't tell which is which I can decipher for you.

 

[ABarrick]

 

[Basher]

The 028 piston doesn`t do anything good for the 026.