Stihl 028 super rebuild went bad

[acarpenterdad]

I use a small 3 stone hone and brake cleaner as lube to do my final pass and set crosshatch, it cuts fast but its only a few strokes. 220grit as i recall, havent had any problems with it snagging ports yet.

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Do you do a lot of them?

 

[SteveSr]

Do you do a lot of them?

The general advice here is to stay away from hones, just like acid. Things can go south in a hurry. The cylinder plating is NOT very thick only a thousandth or two. Red Scotchbrite is MUCH safer, especially to the inexperienced.

 

[acarpenterdad]

The general advice here is to stay away from hones, just like acid. Things can go south in a hurry. The cylinder plating is NOT very thick only a thousandth or two. Red Scotchbrite is MUCH safer, especially to the inexperienced.

That would be me....

 

[Mad Professor]

Muriatic acid method is pretty risky, by the time you realize you screwed up its well past too late...dine right on a viable jug it gets good results though

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From a 036, piston as removed, cylinder cleaned up. I used wet/dry paper (220 to start then 400) and dish detergent by hand. Along with conc. /12M HCl, 2X concentration of muriatic acid/6M HCl

 

[RED-85-Z51]

Do you do a lot of them?

On average 15 a season, mainly trying to save oem cylinders when the customers budget doesn't allow new oem parts and Chinese parts are on the table but not ideal. Open transfer jugs are difficult...

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[acarpenterdad]

From a 036,View attachment 839831View attachment 839832 piston as removed, cylinder cleaned up. I used wet/dry paper (220 to start then 400) and dish detergent by hand. Along with conc. /12M HCl, 2X concentration of muriatic acid/6M HCl

Mine looks similar, condition wise. I will go with a finer grit and clean it good.

 

[acarpenterdad]

Just ordered the piston. It will be in tuesday.

 

[toadman]

Here is where things go south FAST. Muriatic acid will quickly attack and dissolve aluminum transfer but NOT the Nikasil plating. However, if you have any gouges that go THROUGH the plating or get it near the edge of the plating on the ports it will eat underneath the plating and ruin the cylinder. That is why it is safer NOT to use acid.

I ate the bottom out of an aluminum truck box once, after a screw punctured a bottle of muriatic acid meant for swimming pools...

 

[Mad Professor]

I ate the bottom out of an aluminum truck box once, after a screw punctured a bottle of muriatic acid meant for swimming pools...

Ethanol will eat aluminum and magnesium, but slowly, that's why I won't use E10

 

[acarpenterdad]

I got the piston.I'll see if I can check it for fit and get it together this weekend

 

[rupedoggy]

Ethanol will eat aluminum

Hummmm billions and billions of cans of beer

 

[Bob Hedgecutter]

Hummmm billions and billions of cans of beer

Tissue paper thin aluminium to boot!

 

[acarpenterdad]

Here's the numbers for the piston and rings.

 

[mike-s]

Ethanol will eat aluminum and magnesium, but slowly, that's why I won't use E10

Hummmm billions and billions of cans of beer

That's why it's important to regularly rotate your stock.

 

[nitehawk55]

If you haven't installed it check the piston ring gap .

Good luck with that 028 , great saw......my youngest son has 4 of them.

 

[acarpenterdad]

If you haven't installed it check the piston ring gap .

Good luck with that 028 , great saw......my youngest son has 4 of them.

Gap was .010

 

[acarpenterdad]

I got the piston done. Gave it a squirt of gas and it fired right up! Heres the weird part, the compression was so tight i couldnt pull the starter and hold it down with my other hand,so i stuck the bumper spike into the side of my workbench and then i could pull start it. I oiled everything up and used 35 to 1 mix to start it. I checked the compression after that and the gauge would'nt go over 30psi! The only thing i can figure is the gauge is faulty.

 

[acarpenterdad]

I will see if i can finish putting it back together tomorrow and start tuning it

 

[RED-85-Z51]

Id pop the muffler off and have a look...just for peace of mind.

Too much assembly lube can really make them tight on first start

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[Mad Professor]

Hummmm billions and billions of cans of beer

The cans must have a coating much like soup cans do.

Aluminum and magnesium make alkoxides with alcohols, methanol is the worst. The water in E10 contains exacerbates the problem