Cylinder condition and ball hone or not ?

[Scott chandler]

Ok i have read posts on honing and not honing but if this were your cylinder would YOU hone it a tiny bit ? That’s the question and here are the details. 394xp cylinder melted one side of piston had lots of aluminum no scratches gouges or pits - it’s the factory Mahle 56zn9 w1 cylinder - what you see in pics is left over spots of aluminum the muriatic acid and scotch pad didn’t get. I swear you can’t feel it but can see it. I’m tired of scrubbing. Now i have a 2.25” or 57mm ball hone in 320 grit coming tomorrow. Like i said lightly hone slowly forward then reverse and i really don’t know how many times around just in case you want to give me an idea as I’ve never used a ball hone. If you think i should hit it with acid again and scrub more or just stick piston and rings in I’m ok with that too . I’m going to count the for and against and go with majority

 

[smokey7]

I definitely think your not done yet. I would use some 220 wet/dry sandpaper by hand targeting those spots. They will likely go quick. Once they are pretty much gone i would use a brake hone. Meaning a 3 stone spring loaded hone in a 320 grit. Use plenty of k1,diesel, wd40 or similar as lube for maybe 15 seconds total. So probably in out in out in out and look at progress. What im saying is sneak up on the finished product. The ball or "dingleberry" hones dont do good things to port edges. You did good by choosing one very close to your bore size but still risky on a 2t type jug. I would definitely hand sand first before i even thought of putting a hone in that jug. And as far as speed id go as slow as your drill can go to start with getting a feel for whats happening and check progress very frequently. A good clean new stones or dingleberrys will cut very quick. Hope this helps you and i didnt drive you nuts with my spelling grammar and punctuation.

 

[Scott chandler]

Smokey i appreciate the advice so much. I will return the ball hone amd believe i have the other hone in tool box. May have to change stones to 320. I will sand some more on the spots and look for stones or if you know where a complete 3spring hone in 320 could be had i will order. Thanks again

 

[smokey7]

Do you guys have O'Reilly Auto Parts there? I buy my replacement stones there. Or im sure you can buy them on Amazon or ebay also. Take pics of the steps and note the amount of time spent here for others to learn from. Nice saw you got fix it right and will serve you for many more years.

 

[s sidewall]

I'd try acid one more time, then if it didn't come out, sand it.

Steve

 

[Scott chandler]

Do have Oreilly’s but too late - i love amazon . 320 stones and hone will be here Friday. I will do the acid again too. I used an old toothbrush to put acid on with - should i try to scrub with something while acid is working. Since these cylinders are like hens teeth and i had never used muriatic acid on a cylinder before well i didn’t leave it on for just couple minutes then dipped it in baking soda and water tub of hot water then rinsed with hot water. I was afraid i would leave on too long. How long do you let it work and do you scrub with something while it’s melting almuminum ? I wiped cylinder down after it dried with a little wd40. Will repeat tomorrow on the acid thanks fellas

 

[cus_deluxe]

Hard to tell from pics for sure, but looks to me like the plating is damaged around the exhaust port. Get a pick and see if it catches on any of that stuff. I wouldnt put any more acid on there until you are SURE that the plating isnt damaged.

 

[HarleyT]

I'd try acid one more time.

Steve

My wife won't let me..............

 

[HarleyT]

As far as using ball gags.....

My wife won't let me either......



Just sit at the computer, with some emory cloth...

And buff........Until it is all pretty, and clean.

 

[cus_deluxe]

TMI dude...lol.

 

[RedneckChainsawRepair]

Emery cloth for clean up by hand and 240 ball hone for crosshatching finish for me. http://www.brushresearch.com/product-line.php?line=1

 

[Scott chandler]

Ok cus i will post more pics shortly for opinion. No more acid until i hear from you. So if plating is gone can i still use the cylinder ? If it’s just spots will it hold up and have good compression or do i need to start posting in the wants for a 394 cylinder ?

 

[cus_deluxe]

Well im far from the end all haha, and ur pick will prob catch on it if its transfer still too. Maybe theyre just funny shadows, as said its hard to be definitive from pics.

 

[Scott chandler]

Pick catches nothing One spot removed was aluminum. Pictures look like little holes but they’re not. I did hit with 320 paper again. So what happens if i have a tiny spot or two of aluminum left after honing ? Dang piston won’t get here till sat maybe Monday but I’m in no rush for it. Tell me this - as is now with new rings piston will it run a long time if i put 15-20 hours a season on it or less. I got 32 in Oregon bar this evening OMG it’s so long I’m thinking i should have got shorter. I’m not used to working with long a bar - wife speaks up while I’m holding it in kitchen - she says. Amen to that

 

[BuckthornBonnie]

Pick catches nothing One spot removed was aluminum. Pictures look like little holes but they’re not. I did hit with 320 paper again. So what happens if i have a tiny spot or two of aluminum left after honing ? Dang piston won’t get here till sat maybe Monday but I’m in no rush for it. Tell me this - as is now with new rings piston will it run a long time if i put 15-20 hours a season on it or less. I got 32 in Oregon bar this evening OMG it’s so long I’m thinking i should have got shorter. I’m not used to working with long a bar - wife speaks up while I’m holding it in kitchen - she says. Amen to that

If there’s any high spot aluminum remaining then it could damage your piston and you’d be back where ya started.
It’s always hard to speak to longevity of any rebuild, but many of us have reconditioned cylinders working well after many hours. Any transfer must be removed, though, or the over/under guess for hours would be pretty low.
Long bars are fun.

Edit- just looked at your pics again. You’re close, but not there yet imo. Hand sanding discolored areas and more scotchbrite should get ya there. Then clean everything really well, lube, take another pic if ya want.

 

[jltrent]

I have had good luck with final clean up after acid with these. Just use your dremel with cable attached.

https://www.ebay.com/itm/Abrasive-W...469805?hash=item283c8b8aad:g:3oMAAOSw-iNZi51i

https://www.ebay.com/itm/10pcs-Flap...984096&hash=item5d7708a889:g:SMgAAOSwZtlZ7bjK

 

[Scott chandler]

Ok fellas All aluminum gone and up at top there is a spot i will try to show but you can’t feel with fingernail but i can see it and since honing i see a few straight scratches i didn’t see before mostly at bottom of cylinder opposite end of head and i didn’t make them with hone. I’m afraid to hone more unless somebody says do it. I have honed with 320 a total of 35 seconds forward reverse at 5 second intervals and it really don’t take much from the look of the wet dust hence why I’m afraid to do more honing. Here are the pics

 

[Scott chandler]

Fellas i also wanted to ask after reading and watching more on the 394 and why saw scored piston so bad. My plan was to stick rings and piston in and run but - I know splitting case and bearing removal off crank is a real pain especially without the tools and that’s why i thought even though bearings seem fine what about the seals. Read if they have leak then that can cause this problem as well and how well can you check bearings without looking and spinning out of case. Also how tough are the bearings - i mean if saw ran long enough to do this to piston then i can’t imagine what the bearings went through OR do bearings usually survive something like this ? How many of you have had saws that all you did was replace rings and piston ?

 

[Ozhoo]

Every saw is different. If a saw is stopped early enough the scoring is minimal. Saws that stall and get restarted multiple times will be worse. Saws that have been run slightly lean over a longer time will have minimal scoring while one's that have been straight gassed will be heavily scored.

When it comes to bearing inspection, I pull the ignition and seals. Flush the bearing with mix and test for up and down play. Rotate the crank and feel how smooth the bearings are. You'll feel worn out or crunchy bearings. You want the crank to spin smooth as butter.

Your cylinder looks much better. On a personal saw, I'd run it.

 

[Scott chandler]

So oz if i pull magneto and clutch then can you replace seals from outside without splitting case ?