Stihl ms460 build what happened?

[huskihl]

When you polish aluminum transfer it ends up looking like shiny plating. It’s also probable that there’s a sharp edge of plating where the old piston scored and caught it at the bottom of the exhaust port

 

[59billy]

When you polish aluminum transfer it ends up looking like shiny plating. It’s also probable that there’s a sharp edge of plating where the old piston scored and caught it at the bottom of the exhaust port

This observation helped me with something I was dealing with. This is why I love this forum.

 

[Mendocino Redwoods]

Got home from work and had a few minutes to clean the cylinder before my husbandly duties started. I’m back to where I was before. Does anybody with a more experienced eye see anything I’m not seeing. Could the exhaust port chamfering have been damaged from before or even from the scotch brite that I can’t see or feel? I used maroon scotch brite and purple power, should I go over it with something finer?

 

[Mendocino Redwoods]

When you polish aluminum transfer it ends up looking like shiny plating. It’s also probable that there’s a sharp edge of plating where the old piston scored and caught it at the bottom of the exhaust port

I was thinking maybe something sharp on the exhaust port. I just posted some pics it’s hard to get a good angle but maybe you would know what to look for.

 

[Stump Shot]

Got home from work and had a few minutes to clean the cylinder before my husbandly duties started. I’m back to where I was before. Does anybody with a more experienced eye see anything I’m not seeing. Could the exhaust port chamfering have been damaged from before or even from the scotch brite that I can’t see or feel? I used maroon scotch brite and purple power, should I go over it with something finer?

Yes, the affected ports from the previous mishap should be re-chamfered to get any hangers-on off the edge and bore gone over lightly to ensure the chamfer job didn't make a new spot to booger things up again.

 

[Stump Shot]

I was thinking maybe something sharp on the exhaust port. I just posted some pics it’s hard to get a good angle but maybe you would know what to look for.

The metal smear will hang off the edge of the port like a tooth on a crack head.

 

[huskihl]

Need to get up in there with a 1 inch inspection mirror and look at different angles for the plating to be lifted

 

[Wonkydonkey]

Someone correct me if needed.

What I said before and then what Kevin said …

To be sure all the transfer has been removed use a bit of acid (mutaric) and a few seconds to see if it fizzes..

Others may not do this if there competent enough. But I like a guarantee what my dumb eyes can’t see.

 

[Mendocino Redwoods]

The metal smear will hang off the edge of the port like a tooth on a crack head.

 

[legdelimber]

Don't forget to clean the ring grooves and the rings of the piston.
I'm talking about removing the rings from the piston and doing this.
stem of a cotton swab or a toothpick pushed tight into the ring grooves and go all the way around the piston.
Rings get wrapped in a soft rag and worked around a circle in your fingers.

Lastly, take something soft like toilet paper and kind of stuff it into the ring grooves and feel for anything rough.
Also do the ring wipe again, with the TP
You're looking for anything that snags or hangs or feels rough.
Could be embedded debris if you feel something drag or snag.
Also helps you look for a burr or chipped spot on a part.
The paper should be pretty much clean after the wipe, and the grooves and rings dry.
IF you're leaving oil behind still, then you're not completely wiping the parts clean.
Assuming you've gotten all of the contaminants, fleck of plating, aluminum or anything else, out of the grooves and off of the rings.

 

[Mendocino Redwoods]

Don't forget to clean the ring grooves and the rings of the piston.
I'm talking about removing the rings from the piston and doing this.
stem of a cotton swab or a toothpick pushed tight into the ring grooves and go all the way around the piston.
Rings get wrapped in a soft rag and worked around a circle in your fingers.

Lastly, take something soft like toilet paper and kind of stuff it into the ring grooves and feel for anything rough.
Also do the ring wipe again, with the TP
You're looking for anything that snags or hangs or feels rough.
Could be embedded debris if you feel something drag or snag.
Also helps you look for a burr or chipped spot on a part.
The paper should be pretty much clean after the wipe, and the grooves and rings dry.
IF you're leaving oil behind still, then you're not completely wiping the parts clean.
Assuming you've gotten all of the contaminants, fleck of plating, aluminum or anything else, out of the grooves and off of the rings.

Yeah you’re right I’ll take the rings off. I wiped it down with Sea Foam but there’s definitely oil and whatever else the rings.

 

[hacskaroly]

Lastly, take something soft like toilet paper and kind of stuff it into the ring grooves and feel for anything rough.
Also do the ring wipe again, with the TP
You're looking for anything that snags or hangs or feels rough.
Could be embedded debris if you feel something drag or snag.
Also helps you look for a burr or chipped spot on a part.

I like this idea, TP for the win!!

 

[Junk Meister]

Got home from work and had a few minutes to clean the cylinder before my husbandly duties started. I’m back to where I was before. Does anybody with a more experienced eye see anything I’m not seeing. Could the exhaust port chamfering have been damaged from before or even from the scotch brite that I can’t see or feel? I used maroon scotch brite and purple power, should I go over it with something finer?

Simple Green in a USC Seems to help sort the AL Transfer 0n the cyl (The Color) Hard to explain. My Fingernail isn't as trust worthy as a pick when I am checking if the transfer is Proud on the plating or if it is a gouge/score. Reading BRAIL in fine print would be impossible for me.

 

[Mendocino Redwoods]

I appreciate everybody’s feedback. I have a buddy that’s going to clean up the ports. I’m heading out of town so won’t be able to get it back together for at least a couple weeks, I’ll try to do an update after in case anybody’s wondering lol

 

[Mendocino Redwoods]

I'd clean up the cylinder again and get all traces of that old gasket out of the muffler. The piston isn't damaged that badly and will run fine. I'd also flush the bottom end out a couple times with mixed gas. Pressure and vac test it again and inspect everything very well and put it back together.

I forgot to mention it but I did flush it, I soaked the bottom end in Sea Foam for half a day or so and then blew it out 2 or 3 times. I appreciate everybody’s help, you guys are great!

 

[hacskaroly]

I forgot to mention it but I did flush it, I soaked the bottom end in Sea Foam for half a day or so and then blew it out 2 or 3 times. I appreciate everybody’s help, you guys are great!

We appreciate you dropping in, don't be a stranger!! Other people's challenges help stretch our brains!!

 

[geslayton]

Read this thread and got invested in it. Any updates?

 

[Mendocino Redwoods]

Read this thread and got invested in it. Any updates?

Read this thread and got invested in it. Any updates?

Sorry I’m bad with updates… I sent my cylinder to a buddy that ports saws and races them for rechamfering. Since he was gonna grind on it anyway I had him do a mild woods port. I got it back a couple weeks ago but haven’t had the time to put it back together. I’m hoping this coming weekend tho and was definitely planning on posting an update

 

[drf256]

I agree with the polished aluminum transfer sitch. It’s happened to me. Do the acid on the Qtip method all around the ex port. I’d rechamfer the port with a fine diamond ball as well. The fly side floor looks odd to me. Could be an illusion.

I ruined 3 oem pistons on an 1125 build once. Kinda like what you got, linear scratches instead of true scoring. Drove me nuts.

In my case, it was the large end crank bearing that was flaking off. One pin was disintegrating and throwing debris.

IIRC, @Canadian farm boy had the same issue, except his was with the case bearings. One ball on one side decided to disintegrate and toss metal debris inside the saw.

It’s a costly issue.

FWIW, there is zero wrong with going meteor on a 460. They have wider skirts than oem and they weigh a bit more. If you are going 044/46 hybrids, I stick With oem because of the weight savings.

 

[Mendocino Redwoods]

Finally an update! I got the 460 back together and had time for a quick tune before I had to pick the kiddo up up from daycare. It sounds and feels great! I’ll have more time tomorrow to make final carb adjustments with a tach. Lightly sanded and dyed the plastic while i was bored waiting for the cylinder to get back from the porter and parts, I really like how old plastic comes out matte black instead of shiny. The heated handles work and threw on an old 32” Stihl wide nose bar, I wish Stihl didn’t stop making those. I’ll hopefully tune it in wood this weekend. Thanks for everybody’s input!