Question for the porting gurus.

[traffic903]

Hello everyone. I've been hanging around the forums for a while but never posted because I don't yet feel I have the knowledge to contribute.

I would like to ask for some advice as to whether my 044 cylinder is toast. Short story is..........seals needed replacing, very low on compression, heavy scoring (not much transfer) of the cylinder. Tore it all down and cleaned up transfer. Scoring able to be felt easily. So I thought "what's to lose" and took to the cylinder with a rotary tool and some emery (as have successfully done before). Worked at it for a bit but quickly realised that things were going horribly wrong. I had gone through the nikasil directly under the exhaust port. And there is still one vertical score mark which can be felt with my finger. I have some photos which I will attempt to attach but I think I know what you guys will say anyway...........bin it!

Now, on the off chance you all don't say that, my next question is........is it ever ok to remove material below the bottom of the exhaust port and if so/ if not, what effect would that have?

Thanks if you've read this far. Would love to hear some advice (that wasn't totally directed toward me NEVER touching a cylinder again!!)

 

[pioneerguy600]

I would run that cylinder if it was the only one I had at the time. The rings may eventually peel more plating but I have run worse ones on my own saws until I could get a better one.

 

[Little Al]

I would run that cylinder if it was the only one I had at the time. The rings may eventually peel more plating but I have run worse ones on my own saws until I could get a better one.

You have nothing to loose I would leave the Cyl as is & put it back together with a new ring/s correctly gapped & try it If it runs OK for you use it till it coughs Then probably you will need to replace the Cyl/piston up to that point the cost is a ring /set As te saying goe's if it runs run it like you stole it

 

[user 122190]

Looking at that cylinder, it does not look that bad. Put it together and see how it runs. As far as removing extra metal around the exhaust port, sounds unnecessary and is potentially a negative. Removing less metal is better then removing more metal. YMMV.

 

[Stihlhead460]

Are you sure you went through the plating? Hard to tell from the pics, but it looks to me like you just haven't removed all of the aluminum transfer.

 

[Westboastfaller]

Hello everyone. I've been hanging around the forums for a while but never posted because I don't yet feel I have the knowledge to contribute.

That's never stopped anyone before.
Apparently all you have to say is
" Do a vac & pressure test" on anywhere from a deep scratch (in the plastic) to having it been ran over by a dozer.
You will probably get somewhere between 2 to 5 endorsments. Seriously!

It seemed about 6 months ago that was the answer for everything.

The poor art of trouble shooting is lost
Welcome into the forums
All the best

 

[user 122190]

It seemed about 6 months ago that was the answer for everything.

I thought it was pull the carb limiters or remove the muffler and look at the piston.

 

[Deleted member 149229]

I thought it was pull the carb limiters or remove the muffler and look at the piston.

Nobody even asked what the oil mix ratio was!!!!!

 

[alexcagle]

On ones that bad, first I will use a tri-stone hone with WD40 or lacquer thinner to flow the material away. This is kind of similar to block sanding, in that it removes the high spots.
Then I use a dry dremel with a 502, or 503 sand paper paddle wheel bit to finish cleaning it up.
Those dark vertical scores are more difficult to remove, but sometimes they can't be without burning through the chrome first.
One thing I do, is work the surface adjacent to the score line, then hope the then microscopically lowered surface ends up closer to being even with the scoring to help seal the rings better.

 

[brad ruch]

If you remove material from the bottom or top you will change timing on that port.

Sent from my VS988 using Tapatalk

 

[alexcagle]

The bottom of the exhaust port won't matter, unless the piston skirt gets into the port.

 

[pioneerguy600]

The bottom of the exhaust port won't matter, unless the piston skirt gets into the port.

Correct, but even when it does its not as bad a thing as its made out to be. I have saws running fine with almost 1/8" of free port at the exhaust, the saw idles fine and spools up fast, no one that runs it has ever guessed its free porting.

 

[traffic903]

Thank you for your input so far. Stihlhead asked if it is definitely through the plating. The answer is yes - definitely. Can feel the plating edge under the port and I even checked it with acid to be sure. 100% through the plating.

I might try some Cabers in it. So do you think I should grind the bottom of the exhaust port and chamfer the edge so as to hopefully prevent the rings catching on the plating "lip" OR just go with it? If I grind it I may run into a freeport situation as suggested by Pioneerguy. I'm not sure yet, haven't done any measurements for that.

 

[Big_Wood]

i have ran worse, BUT i wouldn't spend $40 on a piston for that jug, different if you have something usable sitting on the shelf.

 

[traffic903]

An OEM piston here in Aus land is $200. That does not include the cylinder, just the piston kit. The piston that came out of it wasn't all that bad really. It cleaned up ok. But now that I have had a better look at the saw I can say that it has definitely had a rebuild before. It has an aftermarket case gasket in it. So that makes sense now as to how I went through the plating so quick. I would say that the last guy to rebuild it took to it pretty solid with a hone. Maybe that scoring was done before the first rebuild and he tried to get it out??

Anyway, all this has convinced me to just go ahead with a Meteor top end and do a full rebuild of the bearings etc whilst I am at it. If I get excited I might even paint it and put on some new plastics. But then it won't tell it's story the same! We'll see. Thanks again.