Plating Advice......

[Poleman]

Hey guys working on a 038 Super that had a broken piston. Ordered a Quality after market P/C. Squish on it needed to be cut over 1 mm.
Got it cut to about .45 and needed to cut more... made another cut and I seen the Nikisil peal around the rim where the bevel was at the bottom.

My question is can this cylinder be used with the plating coming off at the bottom. It's in a non ring area but....
You can see the coating pulled away from the casting.
Rough on another section.

I tried using a diamond burr and 440 sand paper but I am VERY sceptical of long term reliability.

I would REALLY APPRECIATE thoughts on this!!

 

[TreeLife]

In the restaurant industry we had a saying...when in doubt, thrown it out

 

[P.M.P.]

The Godfather will know what to do @tree monkey

 

[Lee H]

If it's smooth i'd run the chit out of it. But that port looks like crap to me.

 

[XP_Slinger]

I wouldn't run it simply because it seams to have had poor plating adhesion. But that's just my paranoid brain, not based on experience with a malfunction of this nature.

 

[jacob j.]

You could probably run that one but longevity wise it would be questionable. If you decide not to run it, I have a used OEM jug you can have.

 

[drf256]

That looks crappy.

Try a brake hone please. Stones just need to be long enough. WD40 in the jug.

When you pull it out of the jug while spinning, it will start to "V" out and will make a perfect factory looking transition the likes of that can't be reproduced any other way I've tried.

Your plating issue may be too deep in the bore for that though. Worth a shot.

OEM 038 (non-mag) jugs seem to be available used for relatively cheap. Supply and demand, everyone wants the mag.

 

[Poleman]

With the advice here I believe I will use the OEM cylinder....I was able to save it other than the broken fins.....just to be safe.

 

[Derf]

I'd worry that if the plating continued to peel, if any of it caught the slap of the piston skirt it could chip off. A small piece of Nikasil in the bottom end could f-up a bearing. Then you're doing a full tear down and case split.
If you could remove the peeling section and the remaining nikasil has good adhesion maybe run it... but not as is.

 

[Poleman]

Deed, your right on what I'm worried about... I'm afraid it will continue to Peak and mess things up bad!!
When the sections came off it was like tin foil.
Now I'm scratching my head on why the squish is so bad on this daw....never seen one this bad. Stock was .65 with a gasket and .45 without. The AM cylinder was around 1.4 mm's the saw had no compression!!!! That's why I was cutting so much on the AM jug....trying to get it respectable.
Anyone else run into figures like this on sa 038 Super??

 

[Al Smith]

On a Mag it's around 46 thou with a gasket .You take off around 22-23 give or take .No gasket drops it by around 20 thou .Some do,I prefer a gasket .
If I recall it's about the same for an AV but you need to remember it has a hemi domed piston so you have to have the soft solder in the correct placement to get a measurement .Super,have no idea never wrenched on one and maybe have seen three in my life time .
Not to poke fun at that cylinder but the name "Quality" is misused .

 

[Poleman]

No domed piston...flat top on the Super.
Quality= Cross

 

[tree monkey]

look like junk to me, I don't mess with AM parts because there not worth what you pay for them. most fail, not wear out

 

[Al Smith]

Depends on the parts I assume .Meteor pistons and Caber rings seems to work out .Use the OEM circlips .

 

[Poleman]

I've had good and bad. I leave it to saw owner what they want......usually AM as they don't want to pan OEM price. It's ALWAYS the CHEAPEST way.........and that's to much.