Husqvarna 181se cylinder/piston

[cornishman07]

Hi, I've taken the top end off my 181 to inspect some piston scoring I could see through the exhaust port and wondered if anyone could offer a second opinion if they're reusable?! I've cleaned them up with some emery and scotchbrite and there's definitely scoring on the piston. The cylinder feels smooth to the finger but using a fingernail does encounter very slight roughness on the section around the exhaust port. I can't tell if it's scoring or transfer! I'm leaning towards the former as rubbing down I don't think has changed it much. The saw ran fine before and I'd like to reuse if possible as it's all original, and it won't get much use at all as I've other saws. Any thoughts welcome!

[pleasant]

Ive seen better tbh. Deffo replace the piston. The cylinder isnt great, but thats just my opinion as im not in the habit of reusing scored barrels....being a main dealer that is a no no, but there are some on here who would maybe give you a better opinion. Its a lot of work to go to, to then find out once its all together you still have poor compression after and back to square one. But, hey its your free time and your arent relying on it to earn money, so maybe worth a try with a clean up and new piston and rings. Remember though you cant buy a cylinder on its own, so if you try a piston and rings, then have to buy a new cylinder, you will be paying for another piston and rings you wont need. 

[cornishman07]

Cheers for that. I've taken apart a few saws in the past and this is by far the easiest to take the cylinder off, it took about 10 minutes, 5minutes of which finding my imperial Alan keys!! It ran fine before and was a beast to turn over. I don't have a compression tester but with the cylinder off I can see the squish band is relatively wide and compression chamber relatively small compared to other saws so whilst compression might be down it felt perfectly fine and was a bit of a brute to turn over! I think I'll clean it up and put it back together for nothing and see how it goes! I have seen meteor cylinder and piston sets are available for about a hundred quid and 288 cylinder/piston drop straight on appartantly so that's a future option!

[pleasant]

Have you established the reason for the scoring before spending time cleaning up your cylinder...or even forking out for a new piston and cylinder....? You dont want to find out you have duff crank seals for example after all your work 

[tenner]

7 hours ago, cornishman07 said:

it took about 10 minutes, 5minutes of which finding my imperial Alan keys!! 

 

Torx 27 will do the job too, funnily enough. I didn't have long enough imperial Allens once and the Stihl t handle bailed me out

 

I'd try that cylinder, think I've run worse. But don't those 181's have NLA pistons with NLA thin rings or some weird consideration?

Edited September 19, 2023 by tenner

[spudulike]

I'm one of the "Some on here" that do salvage cylinders rather than bin them and have generally had good success doing so, no disrespect to Mr P...we all have our ways and didn't have an OEM supplier to keep happy.

The cylinder doesn't look too bad - was this before cleaning the cylinder up...it looks like it. When cleaning it up, don't scrub at a small area with emery paper but do clean in larger rotations around the bore. The former can cause small concave areas in the bore and they can kill compression. The displayed damage looks like a partial seize or "nip up" that hasn't destroyed the cylinder but has caused some damage.

I used to use a cylinder hone to clean the bore up but don't overdo this, you are only giving the new piston a rough surface to bed it in quickly.

On pistons - use a quality brand, Meteor and Hyway are pretty much the best.

As Mr P says - do pressure and vac check the machine checking the seals, rubber parts and manifold etc. Do service the carb on reassembly, do fit a new fuel filter and check the fuel line isn't split and finally....tach the carb to set the flat out running of the saw to ensure it isn't over-revving - you can do this by ear if you know your onions.

[adw]

All seems to have been said, I also have cleaned up and re used cylinders, my go to tool is the flex hone and two stroke oil, lost count of the amount I have reclaimed, I think a cleaned up cylinder is still better than most after market cylinders.

[adw]

Just looked at the piston again that is the original piston that had twin Steele rings and a chrome bore not nikasil, very strange set up and didn’t last to long before a single cast ring piston.

[spudulike]

22 hours ago, adw said:

Just looked at the piston again that is the original piston that had twin Steele rings and a chrome bore not nikasil, very strange set up and didn’t last to long before a single cast ring piston.

Just to add a bit of info...these original rings were really thin and would have reduced friction to allow the saw to produce faster pickup and power.

I guess the friction of two thin rings is probably still less than the single thicker ring just from the reduced springiness and I am now thinking that a single thin top ring would be an interesting experiment for a fast limited use saw.

Is this 181 one of the ex army green ones?

[adw]

I am not sure it would run with jus one ring Steve, the ring end gap was huge, the ring peg did take up some of the gap, you didn’t need a ring compressor, the cylinder just fell on, they used a chrome cylinder because they said there was some sort of reaction between the Steele ring and a nikasil liner.

The last of the 162 and the early 266 also had twin Steele rings however it was never popular and didn’t last very long.

I serviced over 100 green mod 181 and 281 machines, every one had been run with the brake on, you could tie a knot in the clutch spring and shoes and drums were blue, also chain adjuster pawls pushed through the crankcase due to not aligning the bar before tightening the nuts, bloody squad’s