Chainsaw repair-damaged cylinder?

[scrap48]

My Dad had this Stihl 034 laying around collecting dust because someone told him a few years ago it was not worth fixing. I figured I had nothing to lose and would at least I would have a look.

Here is what I found so far. I took apart the cylinder and image 1 shows some scoring at the top of the cylinder near the spark plug.

Image 2 shows some scoring up the cylinder wall near exhaust. The piston looks to be in Ok shape although I will probably replace it.

Any suggestions on how to repair the cylinder or if it is worth it to even attempt?

Would a lean gas/oil mixture cause this?

 

[WVwoodsman]

Hey Scrap,

I am going through the same with a Stihl MS310. You can use muriatic acid and a q-tip to remove the aluminum that has transferred onto the inside of the cylinder. It will take numerous applications of the acid, but each time it's applied it will bubble and fizz as it is removing a little of the aluminum. Make sure you keep the acid solution away from the good parts of the cylinder and wear a mask to protect from the fumes. You should do this in a well ventilated area. After each acid application, rinse the inside of the cylinder with water to neutralize the acid. After you have removed most of the aluminum, you can use a green scotch brite pad or 300 grit sand paper to finish the inside of the cylinder where the scoring occured. As for the piston, you should be able to find an oem one on a well known auction site. If you don't want to spend the money for oem, an aftermarket piston will only be about half as much. If the cylinder can't be saved, it will have to be replaced. You may want to search within this forum for further info on this matter. Good luck.

 

[RAMROD48]

As gray as the top of the inside of that cylinder looks i would say that a straight gas situation happened to that saw...

If the rest if the saw is in good shape i would consider looking for a new top end for it....

That cylinder looks pretty bad...

 

[fearofpavement]

Cylinders are typically steel while pistons are typically aluminum. Often a piston will transfer metal onto the cylinder. As stated above, this "transfer" metal can be removed with muriatic acid. (hydrochloric acid). I use a long wooden handled cotton swab (get some from your health care professional) dip it in acid and wipe it over the aluminum in the cylinder. Aluminum has a much more reactive response to the acid than steel does and it will foam up and essentially dissolve. it will take repeated applications to remove the aluminum from the steel. ie, it can be a time consuming process but can often save a cylinder. In fact, it is often difficult to discern the actual damage done to a cylinder until the transfer metal is removed. I would recommend cleaning the cylinder up even if it looks bad. If nothing else it is good practice.

A piston that transferred metal onto a cylinder is usually ruined. Pistons are not that expensive and many engines can be fitted with aftermarket versions quite inexpensively.

Before using muriatic acid, look up some hazard info on it so you know what you are dealing with. It is safe if used in a safe manner but can kill you if you get stupid with it. A google search will return plenty of data. It is readily available (used in swimming pools, to clean concrete, etc) A masonry supply house would have it and probably even Lone Depot or other big box stores.

When using acid, pour a very small amount into a little container (I use the plastic cap off a cola bottle) and do not return any to the big bottle.

I also do not use ANY water in the process until I am done applying acid.

Let us know what you find out.

 

[fearofpavement]

I should have added that if you fix the top end of your saw to make sure you have eliminated the original cause of the damage so you don't do a repeat. If it was straight gassed, that's easy. An air leak, loose carb, leaky filter or muffler and many other issues can cause piston damage.

 

[pioneerguy600]

Cylinders are typically steel while pistons are typically aluminum. Often a piston will transfer metal onto the cylinder. As stated above, this "transfer" metal can be removed with muriatic acid. (hydrochloric acid). I use a long wooden handled cotton swab (get some from your health care professional) dip it in acid and wipe it over the aluminum in the cylinder. Aluminum has a much more reactive response to the acid than steel does and it will foam up and essentially dissolve. it will take repeated applications to remove the aluminum from the steel. ie, it can be a time consuming process but can often save a cylinder. In fact, it is often difficult to discern the actual damage done to a cylinder until the transfer metal is removed. I would recommend cleaning the cylinder up even if it looks bad. If nothing else it is good practice.

A piston that transferred metal onto a cylinder is usually ruined. Pistons are not that expensive and many engines can be fitted with aftermarket versions quite inexpensively.

Before using muriatic acid, look up some hazard info on it so you know what you are dealing with. It is safe if used in a safe manner but can kill you if you get stupid with it. A google search will return plenty of data. It is readily available (used in swimming pools, to clean concrete, etc) A masonry supply house would have it and probably even Lone Depot or other big box stores.

When using acid, pour a very small amount into a little container (I use the plastic cap off a cola bottle) and do not return any to the big bottle.

I also do not use ANY water in the process until I am done applying acid.

Let us know what you find out.

The cylinder on an 034 is aluminum but coated on the inside of the bore with Nicasil which is much harder than chrome. The acid will dissolve the transfered aluminum from the piston but it is a slow process, heating the piston up before applying the acid helps speed up the process, when the fizzing stops sand the area with 320 grit machine paper, then reapply more acid, repeat as often as necessary to remove all traces of the transfered aluminum from the bore. Be careful to not get the acid into the port openings, there is no Nicasil in there to protect the bare aluminum from the acid.

 

[rallen]

what about staining remaining on cylinder?

I have been surfing this forum to try to better understand when a clean cylinder is clean enough. I now have two that I have been working on, one from an 026 and another from a Husky 335, both with scoring on the exhaust side only.

The 026 cylinder looked terrible when I started, but using both acid and 400 grit paper it came out remarkably well, with one very minor groove that I can't feel with my nail but can see with light. I am going to try that one and see how it goes. There is very little staining remaining from the sanding / acid treatment, and when looking at it with a flashlight, it seems mirror smooth.

The 335 was not damaged as badly. There were light deposits on the cylinder, and I have used acid and q-tips, along with 340 grit paper, to clean it up, but I can't seem to get rid of the "stains" which I assume are remnants of the aluminum deposits on the wall? Again, with the flashlight it appears smooth, but I am wondering if I just need to keep using the acid on q-tips? There is no bubbling when I apply the acid. I also heated the cylinder in the oven at 200 degrees to try to help things a bit.

So are the stains a problem? Do I need to keep at it with the acid even though there is no more visible reaction?

By the way, the 026 was much easier to clean since it is a bolt-on jug, and it was easier to get into the cylinder since it wasn't as deep. The 335 is a clamshell design, and to get at the bottom (top actually) of the cylinder I ended up using a travel-size shaving cream can wrapped with the emery paper and essentially, held the can while turning the cylinder. It took a while but it seemed to work.

Robert

 

[pioneerguy600]

The acid will stain the bore but that is normal, as long as all of the aluminum transfer is gone then that stain will not hurt anything.

 

[3000 FPS]

I went to the local pool supply buisness and bought my muratic acid. They sold me a small amount for 5 bucks. One thing I noticed when cleaning a cylinder with the acid is where ever the aluminum is the acid has a tendency to turn it white. So when you no longer see that change in color you know the aluminum has been removed from that area. Just my observation on this.

 

[rallen]

Thanks! They certainly look smooth, and I am running out of q-tips! I really need to buy some of those wooden stick swabs they sell in medical supply stores. The stain info is helpful and explains why there is a striped pattern from where the aluminum was deposited and where it wasn't.

Now, if I could just find a decent aftermarket piston for the Husqvarna 335xpt. I see there is one on ebay for $25 by Mako, but I have read mixed reviews about them. Bailey's carries OEM for $65, but I don't want to spend that on this saw. And Chainsawr carries a no-name for about the same as ebay price, but again, it is no-name...

Is there another source I should be checking? Also tried Northwood saws...no luck so far.

 

[fir]

Just buy a new one its really not that much even buy big bore kit for it:bang:

 

[carhartt]

I agree the 034 is a great saw. If I was that deep in it and not 100 percent sure on the outcome. Id put an 036 aftermarket piston and cylinder in it. Beefs up the 034 a lil bit. Not that expensive and makes a useless saw valuable.

 

[Brian073]

What are the chances that I can sand/acid this Husqvarna 455 cylinder?

Hey Scrap,

I am going through the same with a Stihl MS310. You can use muriatic acid and a q-tip to remove the aluminum that has transferred onto the inside of the cylinder. It will take numerous applications of the acid, but each time it's applied it will bubble and fizz as it is removing a little of the aluminum. Make sure you keep the acid solution away from the good parts of the cylinder and wear a mask to protect from the fumes. You should do this in a well ventilated area. After each acid application, rinse the inside of the cylinder with water to neutralize the acid. After you have removed most of the aluminum, you can use a green scotch brite pad or 300 grit sand paper to finish the inside of the cylinder where the scoring occured. As for the piston, you should be able to find an oem one on a well known auction site. If you don't want to spend the money for oem, an aftermarket piston will only be about half as much. If the cylinder can't be saved, it will have to be replaced. You may want to search within this forum for further info on this matter. Good luck.

Husqvarna 455 cylinder and piston: https://plus.google.com/photos/1049...s/5883448579962747249?authkey=CMDjgsK67YC57AE

I guess I don't know the difference between "scoring" and "scratches". I can always try the acid and find out, but I would appreciate anyone's comments (as to whether I am wasting my time, or, how long a new piston kit will last). Thanks everyone!

 

[nmurph]

Husqvarna 455 cylinder and piston: https://plus.google.com/photos/1049...s/5883448579962747249?authkey=CMDjgsK67YC57AE

I guess I don't know the difference between "scoring" and "scratches". I can always try the acid and find out, but I would appreciate anyone's comments (as to whether I am wasting my time, or, how long a new piston kit will last). Thanks everyone!

Your link doesn't work.

You can get AL off of the cylinder wall with muratic acid, Scotbrite/sandpaper, and persistance. It helps to heat the cylinder bf you apply the acid.

Scoring below the exhaust port isn't usually too big of a concern, and you can even get away with some very minor scoring above the exhaust. Be careful to monitor you progress as it is easy to have scoring that goes through the plating, and when you apply the acid, it eats the AL transfer and then continues into the cylinder wall and bubbles the plating.

 

[Mad Professor]

If you can find concentrated hydrochloric acid it will speed up the process, muriatic acid is a 2 fold dilution.

Also I use some detergent on wet/dry 300-400 grit sandpaper between applications of the acid. Helps to remove any oil/grease that is coating the aluminum.

 

[Brian073]

Sorry, I'm a newb

Your link doesn't work.

You can get AL off of the cylinder wall with muratic acid, Scotbrite/sandpaper, and persistance. It helps to heat the cylinder bf you apply the acid.

Scoring below the exhaust port isn't usually too big of a concern, and you can even get away with some very minor scoring above the exhaust. Be careful to monitor you progress as it is easy to have scoring that goes through the plating, and when you apply the acid, it eats the AL transfer and then continues into the cylinder wall and bubbles the plating.

Thanks for your fast reply! I tried to add photos as attachments this time; hopefully they will help. It looks like there is scoring above the exhaust port?

Do you think this particular cylinder (455 model) is steel, and the piston is AL?

 

[nmurph]

The cylinder is aluminum, and it is plated with Nikasil. The piston is aluminum with no plating. Muriatic acid, which is a dilute hydrochloric acid, will disolve aluminum but will not touch the Nikasil. Hence, using MA to disolve the AL from the cylinder and being careful not to let it get below the plating (the plating is hard, but it the piston can scratch through it using the aluminum transfer as a scouring agent). I should have added, i think that will clean up just fine.

 

[Brian073]

The cylinder is aluminum, and it is plated with Nikasil. The piston is aluminum with no plating. Muriatic acid, which is a dilute hydrochloric acid, will disolve aluminum but will not touch the Nikasil. Hence, using MA to disolve the AL from the cylinder and being careful not to let it get below the plating (the plating is hard, but it the piston can scratch through it using the aluminum transfer as a scouring agent). I should have added, i think that will clean up just fine.

Thanks for the detailed explanation, I'll give it a try tonight.

 

[Brian073]

You were right...

The cylinder is aluminum, and it is plated with Nikasil. The piston is aluminum with no plating. Muriatic acid, which is a dilute hydrochloric acid, will disolve aluminum but will not touch the Nikasil. Hence, using MA to disolve the AL from the cylinder and being careful not to let it get below the plating (the plating is hard, but it the piston can scratch through it using the aluminum transfer as a scouring agent). I should have added, i think that will clean up just fine.

It's 90% clear now; my hand is too cramped at the moment to finish it. The acid helped some; it may be that my old bottle of acid is just too old.

What I find amazing was when I started, I couldn't tell if there were scratches, or deposits (i.e., whether there were "hills" or "valleys"). It wasn't until the acid slightly changed the color, and then I put it under a strong magnifying glass, that I could see it was all "hills".

I mostly used a piece of thick, curved metal to shear off the AL (to avoid scratching the Nikosil). That worked for awhile. I moved on to small, curved chisels to get the stuff closer to the top of the cylinder, and then a scotchbright pad. I'm close to finished. Hopefully I'll remember how to reassemble it now, ha ha.

I appreciate your comments, and this forum in general! Thanks again!