Guess this piston

[Evan]

ive been meaning to go back in mine and do the transfers and now i just may do like brad and hog out the piston windows.

i have the stock piston i can work over and put in i think i might just do it and see what happens

 

[troutfisher]

Are other guys windowing 372 pistons?

I haven't done it, but it looks like it would work.

 

[blsnelling]

I haven't done it, but it looks liek it would work.

It's hard to say where most of the gains came from. Most of it may have simply been from raising and widening the transfers. But I didn't like that dead space and figured the crown could use the cooling. There were minor signs of heat on the bottom side, barely.

 

[Jacob J.]

Are other guys windowing 372 pistons?

Ed Heard did, Brian has done several....

I put windows in a Jonny 910E piston a few years ago when I was building up one of those, it worked out good. I put it in the hands of a tree service and they used it for several years.

 

[blsnelling]

I'm glad your out there to take the chances and do the experimenting for us! Ha!Ha!

You know, a lot of racers like to keep their secrets to their chest. I suppose that's understandable in a truely competitive world. But I'm only a hobby racer and would rather share what I do than to keep everything I do to myself. I enjoy the interaction.

These mods were pushing the envelope for me. I've never windowed a non-windowed piston before. Not sure I've ever seen it done for that matter. I've also never raised the transfers this much. But I figured, why not. I don't have anything in the P&C, since it was a prototype I tested. Careful planning and attention to detail will normally prevent any catostraphic errors.

 

[blsnelling]

Ed Heard did, Brian has done several....

I put windows in a Jonny 910E piston a few years ago when I was building up one of those, it worked out good. I put it in the hands of a tree service and they used it for several years.

I'm not surprised at all that it's been done before.

 

[bitzer]

Could the same result be had with making windows from the middle of the wrist pin down since the transfers are further down? I'm just thinking structure and longevity.

 

[bitzer]

You know, a lot of racers like to keep their secrets to their chest. I suppose that's understandable in a truely competitive world. But I'm only a hobby racer and would rather share what I do than to keep everything I do to myself. I enjoy the interaction.

These mods were pushing the envelope for me. I've never windowed a non-windowed piston before. Not sure I've ever seen it done for that matter. I've also never raised the transfers this much. But I figured, why not. I don't have anything in the P&C, since it was a prototype I tested. Careful planning and attention to detail will normally prevent any catostraphic errors.

Hey I appreciate man! Its very cool what you do!

 

[blsnelling]

Could the same result be had with making windows from the middle of the wrist pin down since the transfers are further down? I'm just thinking structure and longevity.

Why limit yourself? Look at Stihl pistons and many others. I really don't think it's an issue. Also, I think it's important to have the window near the top. The piston is coming down and compressing the charge. It's going to be pushed to the top of the piston. It would be best to flow the windows from the inside out near the top. This would also give more of a cooling affect. These are just my thoughts.

 

[bitzer]

Why limit yourself? Look at Stihl pistons and many others. I really don't think it's an issue. Also, I think it's important to have the window near the top. The piston is coming down and compressing the charge. It's going to be pushed to the top of the piston. It would be best to flow the windows from the inside out near the top. This would also give more of a cooling affect. These are just my thoughts.

That makes good sense to me. The real reason I am concerned about it is if I burn up the saw(gift from the wife) she'll kick my a$$!

 

[blsnelling]

That makes good sense to me. The real reason I am concerned about it is if I burn up the saw(gift from the wife) she'll kick my a$$!

Just leave a good bridge at the bottom to support the skirt. You'll be fine. BTW, you'll have to raise the cylinder wall at the base of the transfer intakes for this to work. Otherwise you'll be trying to flow charge into an enclosed void.

 

[Jacob J.]

Why limit yourself? Look at Stihl pistons and many others. I really don't think it's an issue. Also, I think it's important to have the window near the top. The piston is coming down and compressing the charge. It's going to be pushed to the top of the piston. It would be best to flow the windows from the inside out near the top. This would also give more of a cooling affect. These are just my thoughts.

When I first started modding saws, I had these same thoughts. I figured that the 372 semi-external loop design would be enhanced by utilizing a partial through-transfer design. I was laughed at by some 'established' builders but it worked out well, as you're seeing now.

 

[blsnelling]

When I first started modding saws, I had these same thoughts. I figured that the 372 semi-external loop design would be enhanced by utilizing a partial through-transfer design. I was laughed at by some 'established' builders but it worked out well, as you're seeing now.

 

[bitzer]

Just leave a good bridge at the bottom to support the skirt. You'll be fine. BTW, you'll have to raise the cylinder wall at the base of the transfer intakes for this to work. Otherwise you'll be trying to flow charge into an enclosed void.

All this for nothin. I just remembered both transfers open next to each other under the exhaust and not on the sides like a regular cylinder. Damn. Well good for future reference and opening other widows! Thanks for the advice man!

 

[blsnelling]

All this for nothin. I just remembered both transfers open next to each other under the exhaust and not on the sides like a regular cylinder. Damn. Well good for future reference and opening other widows! Thanks for the advice man!

What saw are you working on?

 

[bitzer]

What saw are you working on?

Husky 455 strato. The transfers open under the exhaust and come outside of the cylinder and back in. There are metal covers you can take off to expose to transfers from top to bottom

Quickest pictures I could find.

looks like pics don't work

 

[blsnelling]

Ahh, stratos a whole different ballgame.

 

[bitzer]

Heres a pic that might work.

nevermind

 

[blsnelling]

nevermind

Yeah. What I'm doing and talking about isn't likely to work on your saw.

 

[bitzer]

Ahh, stratos a whole different ballgame.

Come on man the are the future! Its gunna be a limp world in a few years. Slow and efficient wins the race!