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372XP X-Torq Modding

Started by XP_Slinger, December 28, 2015, 08:16:01 AM

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XP_Slinger

Hey All,

    I will be tearing into my X-Torq 372XP this weekend and I am looking for the safe squish range for this model saw.  Can I go by the old standard of .020 or more being safe?  I just did a muffler Mod and base gasket delete on my 346XP NE and the increase in performance was well worth the effort, so naturally I MUST tinker with my other saws too.  Are there any other tweaks I can do while I have the 72 torn down? Thanks for any information offered.

Josh
346XP/NE
357XP...ported by MeDremel
372XP/XT...ported by A. Burr
Homelite (Solo) 340

I'd rather be in the woods than on this computer.

49er

I have a 365xt that I have tweaked some. My squish is very close to .020. I used Locktite gasket maker 518. This brought the compression up to 195.
   
Spike60 has a thread covering some basic mods. He described taking a little off the piston skirt to increase intake duration. Ya might do a search.
Husqvarna EC390 365xt
Jonsered 2188 2165 2260 2253 70e
Redmax GZ4000

XP_Slinger

 I am using 3-Bond crankcase sealant.  I will do a better search for X-Torq mods.  Thanks for the reply
346XP/NE
357XP...ported by MeDremel
372XP/XT...ported by A. Burr
Homelite (Solo) 340

I'd rather be in the woods than on this computer.

ehp

there are lots of mods you can do to the XT's , squish I would not go any tighter than .020, I would sooner see .022 . Yep lots of guys go tighter but not me . I run modded XT's everyday logging and have zero problems other than fuel line is junk so switch it out to tygon and no more problems . Remember when you pull the gasket out your also lowering the ext. and transfers so this will also lower your peak torque rpm , yes lowering the cylinder will increase torque but instead of say 9600 rpms you will be closer to 9200 rpms of peak torque if motor was put on a dyno . I myself donot pull the base gasket out , reason it if saw is used real hard everyday 8 hours a day the silicon will at some point fail and cause a air leak as at some point you will get the cylinder temperature up to high and it will fail , doesnot matter what you use , I have seen them all fail . I cut the base of the cylinder and use the gasket

49er

Ehp, do you then raise the exhaust and transfer ports back to the stock location to get the rpm's back? I got a little south bend lathe but I have never cut a base yet.
Husqvarna EC390 365xt
Jonsered 2188 2165 2260 2253 70e
Redmax GZ4000

ehp

No I raise them a lot more than stock, my motors peak torque is at 12,500 to 12,700 rpms and will pull a 36 inch bar setup in hardwood pretty good . I normally run 24 to 28 inch .

Al_Smith

I've never reworked any Husqvarna but I have several Stihls and a couple McCullochs .

I'm with Ed on this one. I like a gasket and about 22 thou piston/head deck clearance .Raised exhaust to maybe 96 degree opening and upwards of 27-30 degree blow down .It jacks about 2000 rpm to them and doesn't kill the torque .

Fact I have the exact same displacement Stihl that will pull a 32" all day and never run hot and never fail to start .

Keep in mind there's much more than numbers   to reworking an engine such as port shapes etc .We might differ in how that's done but end results have  more creedance that opinions  .End results are what really count the rest is just conversation ;D

XP_Slinger

Thanks for all the information guys.  I am still learning about porting and all that and I am not quite ready to get a degree wheel and start grinding.  I am a firewood/hobby guy and since my livelihood does not rely on my chainsaws RPMs I am ok with peak torque dropping by 400ish, my 346 still felt stronger after deleting the gasket despite the drop in peak torque RPMs.  I really appreciate the confirmation of the .020 limit to squish.  My experience with the metal on metal gasket maker is the opposite in that I have never seen the correct compound fail.  Thanks again for all the info. Once my knowledge is higher I will port it the right way, but for now I'll keep going the "Farmer Jones" route.
346XP/NE
357XP...ported by MeDremel
372XP/XT...ported by A. Burr
Homelite (Solo) 340

I'd rather be in the woods than on this computer.

weimedog

On those xtorqs, the squish band is usually nice right from the factory & a base gasket delete gets you right to the .020 range. Of course you have to check the squish...every time! I wouldn't push it closer than .020" either. A muffler mod does help as well in moderation. A common sense thing. I have the choice to either cut the cylinders or not because I have the capability, but on those I choose not to. I do have and know of quite a few Three Bond Builds out there now on a variety of saws in a variety of situations, for several years. Haven't seen a failure yet and on my project saws I've torn down, the Three Bonded cylinders were glued to the cases to where it took a fair amount of effort to break them free. And interestingly enough the only X-torq I have seen with a gasket issue was one with an OEM base gasket. One thing I've been persuaded to do is pull the transfer caps..carefully not to tear and ruin the rubber gaskets & re glue them on with 1184. So I'm not afraid to suggest that Three Bond approach where 2 or three years ago I was hesitant.

I'm not implying that cutting the cylinder isn't a good approach, its been "THE" correct approach for years. My bet is MOST of the true performance saws that were truly professionally (good builders) build have that approach. And those who do it well have latitude for further tuning/porting option those limited to a base gasket delete don't have simply because of geometry. And those who have developed a process and track record with that build process obviously need to continue doing exactly that vs. throw variables into the mix. Right now the process I've adopted and further developed on certain saw builds is using Three Bond adhesives. Not going to change at this point until I see a tangible reason to do so and so far its been exactly the opposite, I'm seeing more reasons and uses for those products to this point. Takes a lot of risk and cost out of the equation. Especially for those who either don't have a machining option or don't want to fork out the additional coin on hobby or project saws. And now with saws that have lived the 24-7 logging world under my belt I'm more convinced than ever that its a valid approach. If any one has been paying attention, I'm a hard sell, a sceptic, but still have that engineering back ground that needs data. Having said that, I not a fan of some of the other "grey" goo gasket products out there. Not because I've see them actually fail because I haven't. It's because when I was doing the research and testing, pulling the cylinders wasn't any where near as difficult as with the Three bond 1194. They pulled right off making me nervous about those products. They still sealed...just a perception thing.
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)

XP_Slinger

Weimedog,

    Your experience is certainly appreciated with regard to Three Bond 1194.  It's what I've been using and hasn't let me down.  Thanks for the squish info, and I always check squish prior to disassembly.  Pretty easy to do the math ahead of time instead of deleting the gasket and reassembling only to discover squish is too tight. 

Josh
346XP/NE
357XP...ported by MeDremel
372XP/XT...ported by A. Burr
Homelite (Solo) 340

I'd rather be in the woods than on this computer.

weimedog

Thank you for the feed back...and I'm always open to new data, not a pride thing with me.

To me the real test is going to be a series of 562's with Three Bond Builds over this year. They do scare me and will certainly be the test that makes or breaks the concept as a general vs. specific solution.

I don't understand the engineering behind the 562. They obviously wanted to get things hot in the front side where the transfer ports are because the muffler design helps hold the heat right there. I guess theoretically the fresh charge from the transfer helps cool therefor picking up heat in the charge before entering the combustion chamber....I don't know. Also there is a clearance issue potentially where the transfer caps & screws may actually hit the cases before the cylinder seats without a OEM base gasket...those gaskets seem to typically be in the .028-.030" range. I have to wonder if any of those saws out there have leaks in the cylinder/case junction because of those caps interfering with the cases. Nothing a die grinder can't fix, but not something you would be looking for. Either way.... that area has to be a worst case for a sealer...so I'm going to test and document that test over time to either verify or question goo gasket concepts... Time will tell.
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)

XP_Slinger

Can't wait to see you results!  I've been toying with the notion of picking up a 562 and would very interested in what you discover.  I am just getting into really learning about porting/modding these little 2 strokes and it's adictive. 
346XP/NE
357XP...ported by MeDremel
372XP/XT...ported by A. Burr
Homelite (Solo) 340

I'd rather be in the woods than on this computer.

old 030

there's a pretty good vid on you tube of the j-red version 2166, they removed the base gasket and trimmed .050 off the intake skirt of the piston, can't remember if they worked over the transfer covers or not, looked to run real strong, the 2166 is shown being run along other j-red and huskys of similar cc or very close to....about a ten minute vid, i found it searching info on the 2166..... ;)

ehp

My 562 cuts almost the same as a stock 395 both saws running the same 28 inch bar and chain in red oak and out cut a stock 372 XT bad , videos are on my youtube  channel and this 562 has cut a pile of timber , they can be made to run very hard

CR888

Do you think, a 555 can be built to run as well as a 562 ehp? I know the 555 is basically a detuned 562 without crank stuffers, smaller transfers, maybe different ignition advance etc. But do you think you could end up with the same result after some effort?

weimedog

Quote from: CR888 on December 31, 2015, 09:25:49 AM
Do you think, a 555 can be built to run as well as a 562 ehp? I know the 555 is basically a detuned 562 without crank stuffers, smaller transfers, maybe different ignition advance etc. But do you think you could end up with the same result after some effort?

Maybe not a 562ehp! Unless the internals, ignition/carb etc. are the made to be the same and thats dollars unless you have a cheap source of those parts. But a 555 can be tweaked to match a 562xp stock.... my question is why? Just buy a 562xp and its a .. match of a 562xp.. :) . And can be built by ehp into a 562ehp. Guess you would have to add up the cost in parts to decide. (I happen to like my stock 555 as it is BTW)
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)

CR888

Ported or not l would not even attempt to run a 60cc class saw 28" B/C in Aussie hardwood buried, not even with full skip. It would laugh at me!lol l like my 555 stock with a simple m/m and have it set up with 15" Windsor rsn in .325 with a 9pin (has to be 9pin if you wanna run .325 due to large spline). But l run a 20" bar on my mastermind ported ms660 and that will bog down instantly if you lift the rear handle with dawgs set. But an ehp 562xp sounds like it would be a special saw for limbing.......but a 16-18" bar is all l would want. Like my 550xp, my 555 performs well stock I think, Husky made both those saws impressive right out of the box IMO, whenever I run them I don't 'wish they were ported'. Instant throttle response, reasonable torque and great handling. I have a strato gutted ms261 that will happily run 16" B/C in the cut 10500-12800rpm.  But she has lost the high production advantage of the fuel efficient strato and fuel is burnt a 2x the pace of my stock one.lol

nitehawk55

About all I do with most is just a muffler Mod . I was going to have one of my 346NE's ported but for now just a muffler mod on it too .
I do have a 346oe that was ported a bit and it runs nice but I'm not out cutting wood and trying to impress anyone . Good running saw  , sharp chain is good enough :)
I AM NOT BRAND LOYAL !

49er

CR888 said
It would laugh at me!lol l like my 555 stock with a simple m/m and have it set up with 15" Windsor rsn in .325 with a 9pin (has to be 9pin if you wanna run .325 due to large spline).


CR888 your 550 should have the small spline clutch drum and it will work on your 555. I put my 2253 drum on my 2260 and used an 8 pin rim. I have never tried a nine but I do have one.
Husqvarna EC390 365xt
Jonsered 2188 2165 2260 2253 70e
Redmax GZ4000

CR888

Sweet!! Good to know as l bought a bunch of cheap stihl RM .325/063 chain that l need to use. I am off to check that out. I have been trying to do something similar with my ms261's that have the 'micro spline' and am thinking a ms260 clutch drum may be the ticket to making them 'small spline' and benefit from the use of AM rim sprockets which l have a heap of. Here in AU, a Stihl dealers retail micro spline rims for $33!!

ehp

any saw pretty much can be made to run if you want to spend enough money and throw enough parts at it , I myself donot like running anything over a 22 inch bar on any 562 , In my area I cut lots of white oak and that wood is really hard to get enough bar oil to the saw , A 24 inch setup is to dry on bar oil for me but at 22 inch it does the job . I only put the 28 inch on it to show people that the 562 can pull it and pull it well, in softwood ya maybe I would use the 28 inch more but not in this hardwood

XP_Slinger

I tore my 72 down yesterday and I'm happy with the results...as expected.  My  squish is now .025 and I also matched the lower transfers to the crank case.  I tried to post pics of the end result but they are the wrong format for this site. Question:  Have any of you trimmed the bottom of the cylinder to get better flow to the lower transfers on an XT?  I didnt, but there is a lot of obstruction that protrudes into the case.  Thanks

Josh B.

346XP/NE
357XP...ported by MeDremel
372XP/XT...ported by A. Burr
Homelite (Solo) 340

I'd rather be in the woods than on this computer.

weimedog


And interesting video from one of the Pioneer's in this game...something for everyone here relative to technic and subjects like base gaskets etc...

https://www.youtube.com/watch?v=IauT5TZskqU
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)

XP_Slinger

Good video but definitely beyond my capability at this point.  Can you offer an experienced opinion regarding trimming down the bottom of the cylinder near the transfers?  Thanks

Josh
346XP/NE
357XP...ported by MeDremel
372XP/XT...ported by A. Burr
Homelite (Solo) 340

I'd rather be in the woods than on this computer.

weimedog

I don't have a X-torq cut that way at this point. So really can't comment. Certainly with conventional 372 cylinders. My concern on those saws is the convoluted piston and resultant bearing surface change along with making certain making that change doesn't interfere with the "xtorq charge" channel cut in the piston. So at this point I wouldn't until I can see it, measure, then test for a period of time.

One thing I do see is now there are after market cylinders to test on! (search Husqvarna 372 X-torq in eBay for the 80 dollar option.) Maybe I'll get a bunch and see what I can do. I have to confess I moved right from conventional 372 cylinders on to 562's this past few months. Kind of skipped over the 372 xtorqs.  With the advent of low cost therefore low risk cylinders to hack at, maybe I'll revisit those.
Husqvarna 365sp/372xpw Blend, Jonsered 2171 51.4mm XPW build,562xp HTSS, 560 HTSS, 272XP, 61/272XP, 555, 257, 242, 238, Homelite S-XL 925, XP-1020A, Super XL (Dad's saw); Jonsered 2094, Three 920's, CS-2172, Solo 603; 3 Huztl MS660's (2 54mm and 1 56mm)

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