372xp

[wyk]

Well,

I went and took some pics and made another vid. The pics don't show how much the exhaust is flared out as it goes into the cylinder, though. It makes the port look straight. I would say it is easily 1/2" wider at the piston than at the exit. Even so, it sorta looks stock to me. But what do I know. It also looks like I may have had a bit of an exhaust leak. I made sure things fit better this time when I put her back in.

Here's the images, the debris is from the paper towel I used to plug it as I was working on the muffler. Next time I am using a cloth towel:

I also went and put a 1/2" hole in the internal baffle in addition the one already there and opened the exhaust a little on the outside:

The thing has a tad more torque now, should I richen her up more - here's a recent vid:

<iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/or8DLH_H1wY" frameborder="0" allowfullscreen></iframe>

 

[komatsuvarna]

Im sure Parrisw can tell ya more about it than I, but I don't remember the exhaust walls being that ''square'' on my stock cylinder. They may have very well been though.

 

[SawGarage]

Well,

I went and took some pics and made another vid. The pics don't show how much the exhaust is flared out as it goes into the cylinder, though. It makes the port look straight. I would say it is easily 1/2" wider at the piston than at the exit. Even so, it sorta looks stock to me. But what do I know. It also looks like I may have had a bit of an exhaust leak. I made sure things fit better this time when I put her back in.


I also went and put a 1/2" hole in the internal baffle in addition the one already there and opened the exhaust a little on the outside:
The thing has a tad more torque now, should I richen her up more -

WYK- it looks like a stock port to me... :dunno:

from the little I heard the saw, I'd say a little richer might help...does it 4-stroke when out of the wood @ WOT??

J

 

[mdavlee]

Looks stock to me too. Is it a xpw topend?

 

[wyk]

OK, here's a vid I did previous to the one I posted before with it at WOT. The chain is dull, I sharpened it before the last vid. Although - that piece of maple I started on is particularly dense. I tried it again and it only cut a tad faster.

<iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/IlwO3VnCFDc" frameborder="0" allowfullscreen></iframe>

 

[wyk]

Looks stock to me too. Is it a xpw topend?

Can't say, Man. I am the 2nd owner. I suppose I could ask the guy. However, it runs as good as my 046 ever did and cuts nearly as fast as my buds 7901. I am pushing hard in these vids trying to bog it with the 28" bar and it doesn't want to. I would think a ported 372 would run much stronger than an 046, tho. I think mine is just healthy.

<iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/njuHgek8R6Y" frameborder="0" allowfullscreen></iframe>

 

[parrisw]

Do you think there's a noticeable difference in the windowed piston vs a stocker? The saw looks like it's got plenty of power.

Yes, I'd say it does make a difference.

This is the fastest 372 I've done yet, and I've never windowed a piston before on them.

AHHH!!!! Goofy guy WAY to close to the Camera @ 6:00!!

oke:


Will, did you have to mod the tank vent @ all??

J

ha ha LOL. Sorry for the big nose shot!

No didn't have to mod the vent.

 

[parrisw]

Was wondering if anybody would notice why I kept looking up. It was that round that rolled away, it just kept going and going and going and going. Was trying to see where it ended up.

 

[blsnelling]

Do you think there's a noticeable difference in the windowed piston vs a stocker? The saw looks like it's got plenty of power.

I window the piston of all 372s that I do now.

 

[parrisw]

Well,

I went and took some pics and made another vid. The pics don't show how much the exhaust is flared out as it goes into the cylinder, though. It makes the port look straight. I would say it is easily 1/2" wider at the piston than at the exit. Even so, it sorta looks stock to me. But what do I know. It also looks like I may have had a bit of an exhaust leak. I made sure things fit better this time when I put her back in.

Here's the images, the debris is from the paper towel I used to plug it as I was working on the muffler. Next time I am using a cloth towel:

I also went and put a 1/2" hole in the internal baffle in addition the one already there and opened the exhaust a little on the outside:


The thing has a tad more torque now, should I richen her up more - here

Looks stock to me. It also sounds stock to me as well. Big difference in sound when you port them.

 

[wyk]

Looks stock to me. It also sounds stock to me as well. Big difference in sound when you port them.

Yeah, I was considering having it ported, but it runs so strong. I am considering actually replacing it with an 064 because I am cutting a lot of big wood and could use a 32"-36" bar. I just really hate those old Stihl bar studs, tho. I'd have to swap them out for the new ones.

 

[SawGarage]

Was wondering if anybody would notice why I kept looking up. It was that round that rolled away, it just kept going and going and going and going. Was trying to see where it ended up.

Captain Sig Hansen just called and said it floated by his Crab boat

I was wondering the same... I said 'OH, I guess we are on a bit of a hill!! LOL

 

[dk27]

difference in the windowed piston vs a stocker

I have about 5 cuts with a 372 that I just windowwed the piston on.
Needed to retune saw,but not sure if that was a seasonal differance.
Taching closer to 15,000k
Does seem to hold power at full throttle better.

 

[parrisw]

I have about 5 cuts with a 372 that I just windowwed the piston on.
Needed to retune saw,but not sure if that was a seasonal differance.
Taching closer to 15,000k
Does seem to hold power at full throttle better.

Is that all you did to the saw? If that's all you did then I wouldn't expect much of anything for gains.

Its really to total package with everything done.

 

[komatsuvarna]

Is that all you did to the saw? If that's all you did then I wouldn't expect much of anything for gains.

Its really to total package with everything done.

I done mine the same as you did Will, except for the popup and milling the cylinder down. I slid the windowed piston in the cylinder to have a look at every thing and I didn't think there was a whole lot of room for flow through the piston windows to the transfers,,, Even though I raised the cylinder walls at the transfers up flush with the base. Kinda like at BDC only the lower half of the windows is exposed to the transfer ports,,, If I'm making any sence here.

Just thinking out loud, But I thought one could be able to squeeze a little more out of it if he raised the walls on up some to get more flow area from the windows to the transfer ports.



































...and It could be that Im too new to this and don't have a clue what I'm talking about.

 

[parrisw]

I done mine the same as you did Will, except for the popup and milling the cylinder down. I slid the windowed piston in the cylinder to have a look at every thing and I didn't think there was a whole lot of room for flow through the piston windows to the transfers,,, Even though I raised the cylinder walls at the transfers up flush with the base. Kinda like at BDC only the lower half of the windows is exposed to the transfer ports,,, If I'm making any sence here.

Just thinking out loud, But I thought one could be able to squeeze a little more out of it if he raised the walls on up some to get more flow area from the windows to the transfer ports.

.and It could be that Im too new to this and don't have a clue what I'm talking about.

No, I think your on the right track. You can raise them higher, Aussie1 does, I think 5mm.

There is definitely more flow that's for sure, it also keeps the crown of the piston cooler.

 

[SawGarage]

Is that all you did to the saw? If that's all you did then I wouldn't expect much of anything for gains.

Its really to total package with everything done.

I think his saw is fully ported... but I wouldn't know for sure...just judging by the sig, and other posts :Eye::Eye:



The ONLY concern i'd see with taking MORE out of the transfer area would be less crankcase volume...but judging by how these run, it seems pretty small to begin with !!

J

 

[parrisw]

I think his saw is fully ported... but I wouldn't know for sure...just judging by the sig, and other posts :Eye::Eye:



The ONLY concern i'd see with taking MORE out of the transfer area would be less crankcase volume...but judging by how these run, it seems pretty small to begin with !!

J

Ya, I've always wondered how much it affects it hogging out the transfers this much, but they seem to like it, so I keep doing it.

 

[SawGarage]

Ya, I've always wondered how much it affects it hogging out the transfers this much, but they seem to like it, so I keep doing it.

I gotta ask 'round and find someone that would mill the case down...we'll see how that works with a window, pop-up, and lots of porting...

gotta swap bearings and the crank anyway ::bang:

 

[parrisw]

I gotta ask 'round and find someone that would mill the case down...we'll see how that works with a window, pop-up, and lots of porting...

gotta swap bearings and the crank anyway ::bang:

From what I've read smaller case compression gives more peaky of a saw.