In a typical performance Slant Six build-up which type of piston ring is prefered? Moly coated, chrome faced or cast iron?

Now, for turbo applications is it different?


bwhitejr

_________________
'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
CompCams 252S, Holley 390cfm, Offy manifold
Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

I have used moly on my motors with good results.

Lou

_________________
Home of Slant6-powered fun machines since 1988

From what I understand, cast iron rings will work ok, though they're not the most wear or scuff resistant. Chrome actually gives the best wear and scuff resistance; so much that on most street cars they will never even "wear in" and you'll end up w/ bad blowby. Moly kind of walks the line between the two, striking a good balance.

_________________
Used to own:
'82 Dodge D150
Erson 270 Cam, O/S valves, mild port work, ~9.5:1 compression

Currently fighting with an '85 VW Cabriolet

My other passion

With high compression, NOS or Turbo race engines, the moly can give you trouble, I have seen the moly "peel-off" the rings.

On street engines, the moly coated rings work well.
Be sure the cylinders are honed to match the rings you plan to use, moly rings need a smooth hone RMS.
DD

When I ordered my engine rebuild kit I requested moly rings. The salesperson said they didn't have them in stock, but they had the cast iron rings. He asked if my cylinders were honed for moly rings, a question I have never heard. Doctor Dodge points out in this post that there is a difference. I honed my own cylinder walls with 100, then 280 grit spreading type hone. I took the cast iron rings and they seem fine on my stock 225 after 800 miles. I'll have to confirm with a compression test after my first oil and filter change.