Rebuild or replace an 038

[JoshNZ]

How much better is a modern 72cc 038 equivalent, than the 038? I imagine it's a bit of a stupid question, rebuild or replace, but I've never known anything else other than this 038 mag.

I got it back from a friend wrecked, scored piston and galling on cylinder I don't know if he did something stupid or if it was time.

The cylinder and piston kit looks pretty available, affordable, aftermarket though.

Would you put a new top end on it, split it and do bearings/seals etc and top, or wreck it and buy brand new? Mostly firewood and for tidying up logs around mill



 

[sawguy21]

At the price of a new saw I would rebuild as long as the crank is good, the big end of the rod looks good with no discoloration. Do the bearings feel smooth and quiet? Maybe a p&c with seals would give it another 20 years, just don't loan it out!! ;D

[Real1shepherd]

How much better is a modern 72cc 038 equivalent, than the 038? I imagine it's a bit of a stupid question, rebuild or replace, but I've never known anything else other than this 038 mag.

I got it back from a friend wrecked, scored piston and galling on cylinder I don't know if he did something stupid or if it was time.

The cylinder and piston kit looks pretty available, affordable, aftermarket though.

Would you put a new top end on it, split it and do bearings/seals etc and top, or wreck it and buy brand new? Mostly firewood and for tidying up logs around mill

Well, looks to me like he straight gassed it and/or used almost no oil in the gas. YOU may never know the full story.

You can scrub down the cylinder walls with muriatic acid and see what it's like then. Lots of P&C kits out there...some of good quality, many of poor quality. Finding OEM would always be a plus unless you can get Meteor.

If it was a great saw for you and the crank is sound, just fix it.


Kevin

[JoshNZ]

The crank is a wee bit grumbly I figure I might as well do the bearings and seals while it's this far apart. It'll need new mounts, and carb rebuild too. It's done a great ~30 odd years of service for us. I've abused it in a milling jig with a 36" bar for a while too.

I suspect the same, mixed wrong or mixed with bar oil, something stupid. Things happen, it's alright. I'll have a look at the crank when it's apart but con rod looks fine, needles and gudgeon were still smooth

I've just got a new saw mill running and I'll need to keep a saw handy with it so I guess what I'm asking is am I any better off with a new tech saw over an old 038 with a new life. Weight/performance/convenience wise. Is there anything I don't know that I don't know. 

[Real1shepherd]

Honestly, I think it's dollars and cents. Unless you spun a bearing and wallowed out the case, providing the crank is OK and you just need new bearings and seals there, I think the saw will restore nicely. Check when you're rebuilding the carb that the throttle shaft has no side to side play.

The money you save rebuilding this old saw against the cost of a new saw should be obvious. I'll let you Stihl boys argue the merits of the new model against this old one. But my guess is that there will be no great advantages to going 'new'.....other than just having something new and shiny.

Kevin

[JoshNZ]

Yeah, good call I think.

What about now... That I've gone and ham fisted the crank seal surfaces...


 

I think I must've slipped with the plyers while pulling the retaining clip out and slid it across the surface. It's not all the way across. I think it'll still seal, a drop of loctite on the scratch might help too?

The cylinder actually looks pretty good, other than the galling, I may try a bit of acid. It's quite smooth. How do you hone a blind cylinder? I've never worked on a head/cylinder cast as one piece


 

This all aside everything else looks great. I do like this saw!

Is it difficult to get the case back together? Crank in freezer bearings in oven and fitted then that lot in freezer, cases in oven, and screw it together?

[Al_Smith]

I've been down this debate road a zillion times .The 038 series is my favorite of all the Stihl line .I have two mags and 1 AV .One of the mags had a grenaded piston caused by 20 hard years of service in a tree service plus it must have swallowed something .No prob,rebuild with a new OEM piston .good to go ..The other  two,mag and AV have been modified .
If you look around you might find a donor .Plenty of after market stuff too .If you wanted to go OEM you can still get the parts .With a proper rebuild that thing will go another 20 years .Don't get stingy with the oil keep it in the shed ,don't loan it out .

[Al_Smith]

On that seal pocket .I have seen that .Permatex won't hold it in but red loctite will .It will take a heat gun though if you ever need to replace it again .

[Al_Smith]

Try the acid but be careful ,fumes  .Use 3M green pads with kerosene  which will get the transfer off but unless to stay at it for hours will not eat the plating off the cylinder .A hone will eat it right up as will a flap wheel .Some try it but I don't advise it .
Now I've got a Lisle precision hone with both stones.steel/iron plus plated like chrome and hard nickle .It will hone a cylinder round with very little taper .I have only used it to hone a cast iron sleeve I turned to repair a big McCulloch but that's another story . 

[Riwaka]

Stihl have had demo saws of the newer models that the dealers could get a loan of in the past. Whether with the covid situation etc that has changed?

The hire shops usually have a few saws usually some of the newer models with the mis-use the saws get in a hire situation.

[Real1shepherd]

Know that whether the cylinder is chrome plated or Nakasil, it's VERY thinly plated. Bailey's sells a ball hone for chainsaw cylinders. But it's extremely easy to go too far into the plating and it happens fast.

What I use is called the Wigglesworth method. I have a rubber mandrel just smaller than the bore. I cut a piece of BROWN Scotch pad to fit around the mandrel....friction fit and go up and down in the bore like a hone with a drill. All you are doing is polishing. I just go to the point where I can't catch my finger nail on anything in the cylinder and stop polishing. A new set of Cabers does the rest.

You should always check that the bore is fairly concentric in three places; top, middle, bottom and that there isn't excessive taper either. If there is, the cylinder gets tossed. You don't have enough plating material to go further with it.

As far as Loctite, use 2620 which is made for high heat applications. Things get hot in a 2 stroke and the only Loctite I trust in this application.

Crank in freezer and bearings heated to 300F....drop right down on the crank....works great. Then you can heat the case halves in a small oven and pull everything together.....lots of YouTube vids on this, so take your choice. Big thing about bearings is NOT to beat on them with anything, if you can help it.  

Kevin

[JoshNZ]

I'll try the acid and then figure out a way to give it a quick polish. If that aluminium bubbles off like I've read it should then I'd say it'll be in good shape. I've got a set of telescopic gauges and a mic, I'll check it's concentric and parallel. Is there something in the manual about diameter? For a 52mm piston what can the bore be before it's out of spec?

[Mad Professor]

I'd try and clean up your cylinder.  Be careful with the acids, have gloves/goggles/ventilation.

Don't get any on the port edges or places where the nikasil might have a hole, it will eat away under the plating,have baking soda solution and water handy for spills and to neutralize the acid as you work.  The acid won't act on oil/carbon deposits.  I hit the aluminum transfer first with some wet/dry sandpaper hand sanding,  and dish detergent solution, then apply the acid with a long q-tip.  Go back and forth alternating the acid with the sanding/detergent.

Hopefully it will clean up.  If not I'd look for a good used Stihl/Mahle cylinder.  For piston OEM is best but Meteor is 1/2 the price.  I'd avoid any Chi-Com crap.

A Stihl gasket set comes with seals.  I'd also look over closely and/or replace the intake boot, impluse line, and fuel line/filter.  If you can pressure/vac test the saw when back together.

Go luck!!! I love my 038s.

[Al_Smith]

It's going to be out of round a tic bit but very very small .It's doubtful you can even measure it accurately  .New rings will seal after enough run time .Those OEM cylinders are tough .I doubt the plating is actual chrome most likely hard nickle alloy .Actual hard chrome became in short supply with a world  wide boycott due to political conditions prior to when those saws were made .

[Mad Professor]

P/C clearance at the skirt should be ~0.0025" when new.  Since nikasil don't wear much with a new piston it should be pretty close to that.

Note that Stihl P/C assys were sized "A" or "B", stamped on top of cyl and piston crown.  Their replacement pistons were "A/B", a compromise that would work with either size cylinder.

[Real1shepherd]

Husky did the same thing with their saws; they often had like three sizes of replacement pistons on their pro saws. Sorry, I misspelled 'Nikasil'.

Yeah, don't get too hung up on the cylinder being concentric.....you're basically looking for a flawed cylinder so you don't waste your time with it. The chrome plated and Nikasil cylinders are amazingly hard. Nikasil is harder than chrome, but the process is also a thinner plate.

I took one of my old loggin' Husky 2100 saws and did the Wigglesworth method along with new Cabers. That saw had seen more use/abuse than homeowner/weekend warrior saws will ever see in three lifetimes. Amazingly, it turned out great. But, it was always tuned right and had the best oil mix run through it at the time.

This guy, Randy, does nothing but repair and port saws. He's considered to be at the top of the heap; people wait over a yr to have him custom port their saws. In this vid he shows you how to get rid of aluminum transfers without acid...AND he shows you the aforementioned "Wigglesworth" Scotch pad method for polishing the cylinder. Part 1 & Part 2
https://www.youtube.com/watch?v=cksVNkI4zps

Kevin  

[joe_indi]

How much better is a modern 72cc 038 equivalent, than the 038? I imagine it's a bit of a stupid question, rebuild or replace, but I've never known anything else other than this 038 mag.

There is no equivalent for the 038, unless it is another 038 or a MS380. With the 381 the Bing carb was dropped for a cheaper Zama.
Even if you have only the bare shell the 038 is one saw that is worth bringing back to life.
I think Holmen Tree who has worked in Stihl will confirm that the 038 had on its design team someone who was on the designing team of the VW Beetle. Not many saws have that kind of lineage

[Al_Smith]

I wasn't aware three sizes of pistons were used on any saw except  81 cc models of the "10" series McCullochs like the 800,805 .850 and SP 81. etc . I've got all the IPL's of the Stihl 038 series AV, super and Mag . I might have the IPL of a 2100 Husky on DVD .

[Al_Smith]

I checked it out but only found 3 sizes of 038 pistons,48,50 and 52 MM ,AV ,super and mag .Where that odd ball size came from I have no idea but it wasn't listed on any IPL I have .I'll check out the 2100 Husky when I get the time .

[Real1shepherd]

I checked it out but only found 3 sizes of 038 pistons,48,50 and 52 MM ,AV ,super and mag .Where that odd ball size came from I have no idea but it wasn't listed on any IPL I have .I'll check out the 2100 Husky when I get the time .

It's old news....there was a A, B, C piston for the 2100/2101 for its long run. You may not find a IPL of all three pistons but I have seen actual pictures of all three, deep in Husky threads on AS.

Kevin

[Al_Smith]

I wasn't questioning it I've just never seen any numbers on the mentioned Husqvarna 2100  .Regarding the web forum you mentioned  I'll check that out the first time I see the sun rise in the west . ;) I haven't looked up my CD or DVD IPL on that model yet but I will if I can find it ..
What I do know is those who tinker with the 2100 find the parts aren't easy to find and some say a 2101 piston will work .Yet  again that fact has nothing to do with a Stihl 038 Magnum .
Now although it's not the subject I do own a 2100CD model that came from some island off the coast of Washington state .I assume it might have been enhanced a tad bit because over the blocks it will out cut the average of those models I've seen .It is also the hardest starting chainsaw I've ever encountered and pulls over just about like rope starting a Harley. 

[Al_Smith]

Indeed it does 501 -61-48     02-03 -04 a-b-c .The 181 also shows three grades but the 281 does not .So much for Husqvarna ,back to Stihl ---

[Real1shepherd]

The 2100CD changed my life. Before that I was using a Stihl 075. An old faller who I was working with, put the 2100 in my hands and everything in my life changed and for many, many yrs after. Every pro has their all time favorite big cc saw, that was mine.

Nobody complained on loggn' shows about saws too heavy or hard to start. You were either built for it, or you went down the road.

Kevin

[Al_Smith]

This one pulls over as hard as an 084 Stihl,which I also own without the decomp being used .This is why I think it's been enhanced a tad .I found the secret,only choke it once else you'll flood it .After a run it fires every time first pull over .It had just sat forever on a barn floor because of a bad coil .I resurrected it with some cosmetic stuff and tuck here and a tweak there .I have a lot of them like that of many brands .I've had several like the OP with the mag and have gotten most of them in good shape .Two in the wings both 99 cc .Mac 1000/Partner P100 .Oh yes and a Stihl 034 super .Restoration is not a game for the weak of heart or impatient I might add . Hours can turn into years sometimes  ;)  

[Mad Professor]

I checked it out but only found 3 sizes of 038 pistons,48,50 and 52 MM ,AV ,super and mag .Where that odd ball size came from I have no idea but it wasn't listed on any IPL I have .I'll check out the 2100 Husky when I get the time .

Al, A B C, that is within a size of Stihl P/C, a +/- ~0.0005.
Most chainsaws mechs can't measure that closely