Stihl and husky rebuild help / advice wanted

[gasax]

Hello all you fine , knowledgeable people , this is my first time on board here and am looking for some help . I recently acquired a Stihl MS271 and a Husky 555 xtorq , both partially disassembled with tore up cylinders . I have no idea the history of the saws . Initial thoughts were straight gas , both tanks have pre-mix (now anyways , maybe added after the fact ?) . With most things involving internal combustion , I prefer to sway towards performance and am trying to figure out if I will rebuild either one or both of these saws and if they would stay in their original configuration or aim for the " bigger,better " direction . Being completely honest , chainsaws are not 100% my thing , my experience with them is limited , certainly compared to most on this forum (which is why I'm here) . I've spent a number of hours now trying to search out part numbers to see what options I would have available and am not having much luck . My main question is displacement , are these engines part of a family / design that share la arger bore ? IE , can I put a MS291 jug on the 271 ? As far as I can tell they have the same exhaust , carb and crank .

Even though I dont use saws alot , I have it in my head since I got these and have been doing some reading that I want a professional series saw . I am being told by people that both of these saws are not professional series and being told by others that they are in the bottom end of the professional class .

I also wouldn't mind doing some porting during the rebuild (if it is to happen) , I have some porting tools but again , not alot of experience (just on my snowmobiles ) . Is there any good resources out there for porting chainsaws , I know they share the same principle as any other 2 stroke engine , I just dont know the math / science behind it . I can figure out port heights and duration with no issue , determining the changes to make is where I'm left scratching my head .

I appreciate any and all input .

 

[Griffdog1]

Buddy I am about to start work on the saw bellow (husky 371xp) and to be honest its a pretty simple process for me now (once you have done a number of saws). First get everything clean then make an assessment of what you are dealing with.
I almost always end up being able to use the original cylinder after an acid clean and some wet and dry sanding with wd40. Clean of the aluminium transfer with the acid and see how you go. If the cylinder is usable I usually go for a meteor piston and caber rings. Shell out for OEM if you like but in Australia the price differential vs the quality differential does not warrant this. If your bottom end feels OK (no play in the main bearings and no up and down of the conrod), just use this as is (don't split cases unless you need to).
Next decision is if you just replace the crank seals as a matter of course or if you take a punt. For you I would pick the best of the saws you have and would do the top end and see how it runs. It is easier to do the diagnosis of a leak on a complete and running saw, and you need the practice of pulling it apart and putting it back together....
Performance wise, I would strongly suggest that you go easy on your first build. That means cleaning up the inlet and exhaust ports, considering a base gasket delete and leaving the transfers alone. Altering port timing is a mixture of science and art and I would suggest you build a few saws before you get to that stage. Maybe port you muffler depending on saw (basically just open up the internals).
I buy a few of the little stihl 100ml oil canisters and use this as a squirter for assembly. Make sure you have cleaned the cases our well. I use a combination of mix swirled around and wd40 blasted in. You are making sure you have all the crap our of there.
- Print of the IPL for your saw so you have it in front of you.
- Rebuild carby and fuel lines as a matter or course with new filters.
- Set carb to factory specs or quarter of a turn further out, with idle screw a little more in to get started.
- Run rich for a couple of tanks before you do final tune.
- Bask in the glory of knowing you built something with your own hands and give the finger to a world that wants people to loose these skills.

 

[gasax]

Thanks for the reply . Both cylinders have vertical gouging , not through the plating but deep enough that it will negatively affect the compression . Either repair or replacement is needed . Is it common to replate these cylinders ? The MS271 is still mostly assembled , looking through the exhaust port I can see the damage ,dead center of the intake side , the 555 is tore up on the exhaust side , aluminum transfer below the the port and gouging above . That is the main reason I want to know if either of these saws have big brothers, if the cylinders have to be replaced and I can do a "factory" big bore , that is most certainly the way Id like to go . Surely there are some gurus on here that have intimate knowledge of these saws...?

 

[muddstopper]

I am no rebuild expert just to be upfront, so take my answer with a grain of salt. I have cleaned up some pretty bad looking cyl just using muratic acid. What looks like gougeing is usually just aluminum transfer from the piston. I put on the rubber gloves, put the acid on a rag or paper towel and just swab out the cyl. Let it set for a while and then used a dry towel to wipe the aluminum transfer out. Might take a couple of tries, but stuff I thought was junk cleaned up almost perfect. Add a new piston and ring and good to go. Doing a vacuum test should be mandatory, but I dont do it because i dont have the right tools. I do inspect the seals to make sure they arent cracked, but that doesnt guarantee they are good. If the saw runs lean once built, I know I need to go back and replace the seals. Not a pro way of building a saw, but what you do if you dont have access to a vacuum gauge.

You can buy a lot of after market p/c kits on line pretty cheap. I have tried a few with mixed results so do your homework. I wont suggest a brand or distributor because I havent tried most of them. I will advise to check the squish to be sure its within specs and since you said you know how to check port timing, I would do that also. Might have to do a little grinding to get the numbers right, but if you really want to do a full port, you need more info than I can give you. Heres a good read to get you started, http://www.macdizzy.com/cyl_primer.htm and you can search this site for the thread porting 101, lots of chainsaw specific info there.

 

[RIDE-RED 350r]

I don't know much about Stihls, but I can tell you a couple of things about your Triple-Nickel... It IS built just like the "pro grade" saws Husky offers with a magnesium crankcase. It's only "big brother" is the 562XP. But the 562xp and 555 share the same engine with the same bore, stroke, and displacement, only the 555 is a detuned version. It really is a clone of the 562XP but with a little less attitude. So having said that, there aren't any options for putting a different top end on of larger displacement like you can when you put a 372 top end on a 365 for example. The 555 is well worth fixing, even if it requires a new cylinder, it's a very solid saw.

Do heed the advice above, many cylinders that look too far gone end up being saved and very usable after cleaning.

Being that these cylinders do not have removable heads, I don't know that you will find many that will replate them. And given the cost of just buying a new OEM cylinder, replating probably isn't even economical knowing what the average cost is to replate a dirtbike/wheeler/sled cylinder...

 

[gasax]

OK fellas , I'm going to go bust out the muriatic acid and see what we end up with with the husky cylinder . The gouge in the stihl is enough that I can feel my seal pick drop into it and I really don't hold any hope at all for it . The husky jug actually looks like someone tried to clean it with a hone .

I've been through the Macdizzy site before ,although it wont hurt to read it again, it is a great resource , I will search for the porting thread on here .

As far as the 555 and the 562XP , do you know what differences they have regarding the tuning ? do they have different porting or is the tuning differences with the timing / carb / exhaust ?

 

[RIDE-RED 350r]

For one thing the 562xp has "Rev-Boost" where the 555 does not. I believe the 562 has case stuffers where the 555 does not. There may be some differences in the port layout, but I am not 100% sure of that.

 

[gasax]

 

[gasax]

I didn't go at it too long but the transfer below the port cleaned up pretty good with the acid , it isn't doing anything for the damage above the port though .

 

[RIDE-RED 350r]

Damn, that does look like damage to the plating. 555 cylinder?

 

[gasax]

Yes , that is the cylinder from the 555 . I got both of these saws from a "junk / odds'n'ends" lot at an auction . The rest of the lot turned out to be well worth my investment and being the saws are current models , I wouldn't mind putting some money into them to make them go again . The Stihl OEM cylinder price I came up with was twice as much as the husky though , I wonder is that the norm ? The Stihl's cylinder is incorporated into the upper crankcase so maybe that is why the difference in price ?

We have 4 Stihl's here , I have never had anything to do with a Husky but I'll try anything at least once , lol .

 

[weimedog]

Too much to read through. ..but seemed like one of the questions was related to 555 & 562. Key differences;
Large mount vs small bar mount. (555 small)
562 has stuffers, 555 no crank stuffers, cranks themselves are different too.
different ignition & carb
different plastic
different price!
Different clutch cover because of different cases.

 

[weimedog]

Rebuild. ...do not do things like base gasket deletes unless you are willing to do some machine work. Build them stock unless u have a machine shop skills and can trim the "flange". Also relieve the cases under the transfer covers...basically stock unless u are skilled

 

[weimedog]

Also get a dealer to update the firm ware. Older 555's had the five screw cases which would leak under the muffler. ..but three bond could fix it.

 

[weimedog]

Great saws stock and even more fun tweaked.

 

[MountainHigh]

personally I wouldn't spend much time or money on a 271, but would spend the time and money on a 555 - and this is not a brand preference thing, I just think the 555 is a saw worth keeping.

Stihl 271 - $500 CDN new ($382 US)
Husky 555 - about $800 CDN ($600+ US)

 

[tomdcoker]

View attachment 559663

If you can feel the gouges (they look like gouges) with your fingernail you will loose to much compression on that cylinder and it is not use able. My option. If you use muratic acid to cclean a cylinder be sure to not inhale the fumes and heat the transfered metal before using the acid. It helps. You will know that it is working when you see bubbles. I use a hand held tourch for heat. Tom

 

[muddstopper]

I just set mine on top of the stove to heat them up. I have also been known to wipe with the acid and leave over nite. Next morning the transfer is nothing but powder. Doesnt seem to hurt the cyl, but then again I only wipe the bore.

 

[weimedog]

That cylinder looks like it's toast.

 

[gasax]

Thanks for the replies , alot of good info . The husky certainly has the majority of my attention atm , I will get more bang for my buck in all aspects with the 555 , power , cost , and value with everything I am seeing at this point . I don't care to to try run a tight squish , the risk / return just isn't worth it to me , I would rather stick to improving flow and maybe some mild porting .

So what I am thinking is , a 562 cylinder and piston , the cups for the crank and an ignition coil . Essentially a 562 conversion . The coil , from what I gather , probably has the most effect for the performance difference between the 2 saws, with the 562 coil having revboost and an extra 1k rpm .

Does anyone see any issue with my plan ?