I purchased a used non running Stihl MS440 recently. The previous owner stated it had 152 PSI of compression. I was wondering if the cylinder could be re-used. It appears the plating is worn off in a few spots and the cross-hatch is largely non existent. I would like to just try to hone the cylinder if it can be saved. What are the service limits on the cylinder? I have attached a few photos. Thank you for the help!
Stihl MS440 cylinder. Is it garbage?
- Thread starter jl428
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Usually, it is not the plating worn off. But, melted aluminum from the piston.
There is chrome or nikasil plating on the cylinder that is really tough compared to an aluminum piston.
What melts off of the hot piston on to the cylinder is referred to as transfer.
If you can get that clenaed off and not damage the cylinder plating the cylinder will be fine.
Not sure what you mean by cross hatch, but that is another engine design.
There is chrome or nikasil plating on the cylinder that is really tough compared to an aluminum piston.
What melts off of the hot piston on to the cylinder is referred to as transfer.
If you can get that clenaed off and not damage the cylinder plating the cylinder will be fine.
Not sure what you mean by cross hatch, but that is another engine design.
Thanks for the info. I am not an engine or cylinder expert but I thought all cylinders had cross-hatching to allow some room for a thin layer of lubrication to stay between the piston and the cylinder as the engine is operating.
Jza
ArboristSite Member
This is off my 661 , quick flick with some sandpaper , a hone and it runs like a beast. Even has good compression with those gouges
I'd give it a hone see how it looks . If your happy , go oem rings and break it in hard !
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Cross hatching is a pattern that will help the rings seat to the bore. It IS important! Again, we are not honing to increase bore. We are only breaking the GLAZE that will inhibit the seating of the rings.
And yes, I have seen saws that were assembled without breaking the glaze with low compression. Cured by breaking the glaze so the rings can seat.
Can be done by breaker with stone, emery cloth, sandpaper, etc.
Part of rebuilding any engine using piston rings.
And yes, I have seen saws that were assembled without breaking the glaze with low compression. Cured by breaking the glaze so the rings can seat.
Can be done by breaker with stone, emery cloth, sandpaper, etc.
Part of rebuilding any engine using piston rings.
There is no cross hatch in any Stihl cylinder since the 241. A 500i cylinder is like a mirror inside.
So I’m not sure it’s entirely necessary in a chainsaw
With time on a cylinder it may disappear as the rings seat perfectly to the bore. It is needed to wear the rings to the bore. Just engine basics.
We must have different ideas about what cross hatch is.
I’ve ported a couple hundred new Stihls. There’s no crosshatch when they’re new
No crosshatching on cylinder, pistons have fine horizontal lines to achieve the same function
That cylinder does not look bad to me. I have had success cleaning aluminum transfer before. Andy (Lakeside) walked me through the process a while back. Q-tips and muriatic, and purple cleaner to neutralize afterward. Aluminum transfer come off green on the swab. Keep changing swabs until they're no longer green. Be careful to not touch the aluminum in the ports. I am not an expert on rehoning; I tend to think that whatever plating is left needs to stay on there. The rings eventually seat on a smooth cylinder wall, right?
Good luck. It looks WAYYY better than a slant fin 044 jug I bought on eBay recently, advertised as soft-seizure transfer, but has a scratch about half a milimeter deep, and piston ring pieces embedded in the top. Won't be using that one...
Those lines are ton retain oil...No crosshatching on cylinder, pistons have fine horizontal lines to achieve the same function
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