cooltoys61

Stupid question and I think I know but want to be sure. My Fed Mog seal power cast pistons have NO indication of top and second,,I assume the top is the rough/black finish outer edge with a bevel on the inside bottom edge.The other has a smooth almost silver outer edge with looks like no taper or bevel in or out (I think for the second groove). Instrucsions show all the various style avail and which way is up but not which is which. Do I have it right.Thanks for helping.

Monty

Usually the top ring has a dimple on it, which goes up. If there isn't a dimple, then there's usually some "paint" in the rings at the gap to differentiate them. Usually it's purple, green or yellow depending on the brand. It sounds like you have a ring set with a moly upper ring, which is good because they seat almost instantly. The ring that has the shiny edge is the moly impregnated ring and that's the top ring. The second ring is usually just cast iron and it has a duller finish, it will also have the bevel so that it can flex and scrape oil better as the piston moves up and down.

mcollinstn

umm, sometimes the bevel goes up.

Monty

True, but if he's got plasma-moly rings, the one with the silver outer edge is the top ring. He said only one ring has a bevel; the one with the dull finish, while the shiney one has no bevel. High-performance rings usually feature a bevel on the top ring for high-rpm compression sealing and on the second ring to aid on oil control. The second ring in a conventional ring set (non-"zero gap") is primarily an oil control ring and will almost alwayts have a bevel in all but the cheapest ring sets.

cooltoys61

They are regular $40 rings from Summit, supposed to be cast. Both have the dimple showing "up"and now I see one has white paint the other baby blue ,,I didn't mention before because I thought they were both white. At least I don't feel like its a stupid question now. The slightly silver/chrome edged ones are ,if you look very closely, spotty with grey looking tiny spots on the edge. Now that I reread the instructions it says "typical economy rings instalations" but also says if there is a "chrome or moly" ring to use it on top.

cooltoys61

Slp-e-233k $46.95

Monty

According to Summit's website those are:

Piston Ring Set, Chromemoly, 8 Cylinder, 4.250 in. Bore, 5/64, 5/64, 3/16

The rings with the shinier outer edge are the plasma-moly rings which ar ethe top rings. The dot faces up.

Be sure to check your end gaps before installation, even if they are not file-fit.

cooltoys61

thanks,my gap is .019. That should be plenty,right?