6.2 piston damage from glow plug

[TrenchFoot]

While cleaning up my pistons I started questioning my plan to reuse this piston. Obviously, a glow plug tip dropped in a while back and decided to stick around.

http://farm8.staticflickr.com/7418/11662546214_4170ffcc3a.jpg

and there's nicks scattered around the top, nothing deep.

http://farm8.staticflickr.com/7360/11662982706_01215fb8dd.jpg

So what do you think? Think it needs to be replaced or is this normal, albeit regrettable, 'character' that can be lived with? (And let's talk reality here. Not shop-manual, perfect world 'best practices', or prepping for a trip down the Bonneville salt flats.) It appears that this piston (#7) ran fine for some time after the carnage since the glow plug had been replaced by the time I tore it down.

If it needs to be replaced what else has to be ordered too: pin, bushing, retainer clip?

Many thanks again TDP's Best and Brightest!
-Trapper

[DmaxMaverick]

If there are no cracks, and the "damage" isn't near the edge, polish it out (remove any sharp edges) and move on. No harm. That doesn't look bad, at all. I've seen a LOT worse that worked out just fine. No more 9G (or similar aftermarket) plugs.

[john8662]

Add 11G's to the list too, they're as bad as the 9G's if not worse about swelling. I've had the pleasure of removing a few of the 11's lately that were swollen (removal the hard way).

I agree with the statement above, the piston doesn't looked harmed up top, file down any high-spots.

Check the wrist pin bosses for any cracks and later with a pin on a rod and feel for slack, you'll probably be good to go though.

J

[TrenchFoot]

Thanks for the quick response guys. I have a set of ACDelco 60Gs waiting to go in. I'm glad to hear I can continue forward progress with what I have.

Any advice on cleaning the 9 small grooves around the top circumference of the pistons? Mine are all filled with carbon and I suspect they're designed to make a labyrinth seal to limit oil burn. I've soaked my piston heads in almost every solvent I can find and the only thing that works is a tedious scrape with the edge of a razor.

9 grooves x 4" diameter x 3.14 = 112" of groove per piston. There's gotta be a easier way than scraping 9'+ with a razor on each piston...

Or is this a waste of time and those grooves will clog up in the first hour of run time?

http://farm3.staticflickr.com/2818/11673092036_749b59da56.jpg

[sctrailrider]

wire brush.....

[argo]

Thanks for the quick response guys. I have a set of ACDelco 60Gs waiting to go in. I'm glad to hear I can continue forward progress with what I have.

Any advice on cleaning the 9 small grooves around the top circumference of the pistons? Mine are all filled with carbon and I suspect they're designed to make a labyrinth seal to limit oil burn. I've soaked my piston heads in almost every solvent I can find and the only thing that works is a tedious scrape with the edge of a razor.

9 grooves x 4" diameter x 3.14 = 112" of groove per piston. There's gotta be a easier way than scraping 9'+ with a razor on each piston...

Or is this a waste of time and those grooves will clog up in the first hour of run time?

http://farm3.staticflickr.com/2818/11673092036_749b59da56.jpg

When I did mine 4 years ago, I dipped the pistons in Berryman B-12 Chemtool. It is really nasty crap that you do not want to get on your hands, but it will dissolve just about anything. This is what carburetor shops use to soak gummed up carb parts. It will dissolve skin too if you are not careful, so get gloves if you go that route. You can get it at most auto parts stores. The only downside is you can probably only do 2-3 pistons at a time in a single can. It is the ultimate for returning your parts to brand new appearing shiny bare metal. In the event it doesn't completely dissolve the gunk, it will be so soft that you will have no trouble flaking it away with a toothbrush... until the toothbrush dissolves.

[DmaxMaverick]

When I did mine 4 years ago, I dipped the pistons in Berryman B-12 Chemtool. It is really nasty crap that you do not want to get on your hands, but it will dissolve just about anything. This is what carburetor shops use to soak gummed up carb parts. It will dissolve skin too if you are not careful, so get gloves if you go that route. You can get it at most auto parts stores. The only downside is you can probably only do 2-3 pistons at a time in a single can. It is the ultimate for returning your parts to brand new appearing shiny bare metal. In the event it doesn't completely dissolve the gunk, it will be so soft that you will have no trouble flaking it away with a toothbrush... until the toothbrush dissolves.

The original B-12 contained MEK (methyl-ethyl-ketone), and it will, eventually, dissolve just about anything. Good stuff, but lethal! Used a lot of that stuff in the military, some 30 years ago. I still use B-12, but haven't checked the contents lately.