High Quality Chainsaw Bars Husqvarna Toys

New Build. 372xp case, an X-torq cylinder and a 575xp piston.

Rich Fife

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As the title says... I have a 372xp case, an X-torque cylinder and a 575xp piston...
This will be a complete ground up build...
 

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Rich Fife

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The cylinder is in relatively decent condition.
 

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Rich Fife

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50mm vs 51mm y'all see where I'm going with this?
There are obvious differences between the pistons, but... despite the 575xp being 1mm larger, it does have some perks. It's currently 5g heavier than the X-torq piston... I'm not worried about that as I'll be removing material in the lathe. I'll mirror the x-torq dimensions... the 575xp piston should be lighter than the x-torqs with room to make it even lighter. The piston intake landing is wider in comparison which will allow me to widen the intake on the cylinder. I know a lot of people don't play around with the strato ports... but, I do. I open them up and try to slow the fresh air velocity... on some saws I introduce a small fuel charge... the last X-torq I built was a monster... the guy put his prized 460 magnum on the shelf and exclusively runs the X-torq.
Anyway, this should be an interesting build.
 

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Ketchup

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Neat. I’ve always wanted to shave a piston to fit. It would be great to have more piston options in the strato saws.

How are you going to address the ring pins? That skirt cutout on the 575 slug won’t freeport?
 

Rich Fife

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Neat. I’ve always wanted to shave a piston to fit. It would be great to have more piston options in the strato saws.
Agreed
How are you going to address the ring pins? That skirt cutout on the 575 slug won’t freeport?
The ring pins clear all ports. I'll post a pic later showing that even with the large cut-out there's still approximately 1/4" or more of material before it free ports.
 

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Agreed

The ring pins clear all ports. I'll post a pic later showing that even with the large cut-out there's still approximately 1/4" or more of material before it free ports.
Sweet. I think I can see the exhaust port penciled in on the XT piston, but it’s so high I wasn’t sure if it was TDC.

On the pins, I meant how are you going the spin the piston down without affecting the holes? Are you planning to machine the ring lands deeper? People say if you mess with the pins you increase the chance of one coming free during operation. I think they’re just interference fit, so I could see how the holes would enlarge if you punched them out. I wonder what they’re made from.
 

srcarr52

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If you don't want all that intake duration from the cutout in the 575 piston I've tig welded those cutouts in before. Since you're going to cut 1mm off it anyway it would be easy to do before you chuck it up in the lathe.
 

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If you don't want all that intake duration from the cutout in the 575 piston I've tig welded those cutouts in before. Since you're going to cut 1mm off it anyway it would be easy to do before you chuck it up in the lathe.
Isn’t the cutout on the exhaust side? What are your thoughts on the ring pins? Relocate them?
 

Rich Fife

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Sweet. I think I can see the exhaust port penciled in on the XT piston, but it’s so high I wasn’t sure if it was TDC.
Yes, that was at TDC.
On the pins, I meant how are you going the spin the piston down without affecting the holes?
The pins are recessed slighly, im hoping that when i remove the material that i wont touch the pins... if it happens, im hopong i can heat the piston and remove the pins. And then either drill deeper and make new pins. Freeze the pins and heat the piston and create an interference fit.
Are you planning to machine the ring lands deeper?
yessir
People say if you mess with the pins you increase the chance of one coming free during operation.
people also say if you port a saw it wont last as long.
I think they’re just interference fit, so I could see how the holes would enlarge if you punched them out. I wonder what they’re made from.
Agreed, I'll find out here in a little bit. Lol
 

Rich Fife

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If you don't want all that intake duration from the cutout in the 575 piston I've tig welded those cutouts in before. Since you're going to cut 1mm off it anyway it would be easy to do before you chuck it up in the lathe.
How does the piston hold up after tig Welding on it?
 

Rich Fife

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Just fine, weld a little bit at time so you don't overheat the rest of it.
I probably won't mess with it this go around. I want to use this build as my baseline... and when I do another, I'll try what you recommended. I have (10-15) junk 372xps and x-torques to play with. I'll be able to dial this build in.
 

Stevetheboatguy

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Couple things I'm sure you know, but should be mentioned. #1 the pistons are never perfectly round. Always egg shaped/cam ground. #2 the intake landing will shrink when turned to 49.whatever mm.

I hope you have good results and the points above are proven to be a non issue. But needed to point them out so less inclined knew the full scale of what you are up against.

Steven
 

Rich Fife

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Sweet. I think I can see the exhaust port penciled in on the XT piston, but it’s so high I wasn’t sure if it was TDC.
Below you can see the line where this piston would be at TDC.
On the pins, I meant how are you going the spin the piston down without affecting the holes?
Are you planning to machine the ring lands deeper? People say if you mess with the pins you increase the chance of one coming free during operation. I think they’re just interference fit, so I could see how the holes would enlarge if you punched them out. I wonder what they’re made from.
Had a brain fart... I will have to remove the ring pins or make a jig and machine the rings inner diameter... which way do I go. Lol
 

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Rich Fife

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Rotary table on a mill with a really small end mill to machine the groove diameter?
Thay would work, but, a lathe would be much faster. I'm going to try and heat the piston and remove the pins,if that doesn't work I'll turn them... drill and make new pins... probably relocate them as well... time will tell... as I'm not sure the route I'll be heading.
 

Rich Fife

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Basic checks
 

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