OEM or Caber

[Tumleweed66]

I scored an OEM ms390 cylinder and piston on the bay and the piston has the oem cast rings ( I'm assuming they're the factory rings) ... my question is should I spring for a set of Caber rings or just use the Stihl rings?

 

[Maintenance supervisor]

The oem are on par with Caber rings.

 

[Tumleweed66]

The oem are on par with Caber rings.

Those markings on the rings is that the oem

 

[grizz55chev]

Those markings on the rings is that the oem

Run em! It's a 390, not an 036. Homeowner saw should be fine, just check the ring gap.

 

[Maintenance supervisor]

Those markings on the rings is that the oem

Really only Oem and Caber have markings on their rings , possibly some high end racing rings would too .

 

[ApePilot]

I scored an OEM ms390 cylinder and piston on the bay and the piston has the oem cast rings ( I'm assuming they're the factory rings) ... my question is should I spring for a set of Caber rings or just use the Stihl rings?

I'd try the OEM (made by Komarov), but also ensure that the gap is acceptable (0.1mm gap per 25mm bore or slightly more). But also check the gap in a few hours of run-time. My Husqvarna 3120xp OEM piston+rings (labelled 'KO B8') had not only too much gap at installation, but within an hour and a half of run-time, the rings wore far past the replacement gap specs (0.25mm gap per 25mm bore or greater). My saw ran great right off the bat with the new rings, but then seemed to loose some power over the course of one hour or so. Yes, fuel and oil was good (100LL / Maxima K2 @ 25:1) and A/F mixture ratio was adjusted perfectly to the fuel as I have a WB-39 carb set-up with high and low speed needles; top and bottom piston surfaces indicated it to be perfectly cool-running.
Your rings (KO MC23) may be of a better, harder cast material than the Husqvarna OEM junk rings that I experienced.
-doug