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  1. #1
    Join Date
    Aug 2002
    Location
    ELBERFELD INDIANA
    Posts
    141

    Default cast or chrome molly rings

    got chrome molly rings for my build up. but am hearing this is not a good choice. have 462 with ross 11-1 pistons. does this make a difference if your compression is gonna be high when considering cast or chrome molly? dont want to do this twice. used chrome molly before in olds,pontiac and chevy with no problem but buick is a lot more expensive to fool around with.just need some advice
    70 stg.1
    464 C.I.TA PERF. 413 CAM,ROSS FORGED RACING PISTONS,11-1 COMPRESSION, SP1 INTAKE WITH 850 DOUBLE PUMPER SPEED DEMON, MSD6AL WITH DIAL REV LIMITER,BILLET DIST AND SUPER CONDUCTOR WIRES, M/T SUPER COMP. HEADERS
    STREET STRIP PORTED IRON HEADS
    ACC BOSS HOG 3500 STALL 12 bolt 3:42
    http://www.youtube.com/watch?v=1PTn9PsPsLw

  2. #2
    Join Date
    Dec 2008
    Location
    Dayton TN. halfway between Chattanooga and Knoxville TN.
    Posts
    252

    Default Re: cast or chrome molly rings

    Barry,
    The theory/fact is that under racing conditions, the rings will run hotter than in a "street" type application. That is the reason for the moly. It is suppose to be able to withstand this extra heat and keep a proper seal while doing so by avoiding flaking and scuffing of the ring.
    The problem that your going to have is, I am almost positive that the Ross pistons only accept 1/16 rings on the top and second groove which you can only get the moly type rings for.
    The 1/16" rings are thinner and take less effort to move in the bore. Thats the main reason the race piston manufactors use the 1/16" rings in there pistons.
    Cast rings only come in 5/64 that I'm aware of.
    Jim

  3. #3
    Join Date
    Dec 2008
    Location
    Dayton TN. halfway between Chattanooga and Knoxville TN.
    Posts
    252

    Default Re: cast or chrome molly rings

    Barry,
    forgot to add... moly rings are fine. Just dont get ahold of the old cast chrome coated rings. Most racers stopped using them 30 years ago when moly was introduced.... but there are still some of them out there!
    Actually the cast chrome rings are okay... but the molys are better.
    Call Mike at TA or Jim at Trishield if your really worried about it.
    Jim

  4. #4
    Join Date
    Aug 2002
    Location
    ELBERFELD INDIANA
    Posts
    141

    Default Re: cast or chrome molly rings

    the ross pistons come from poston and take 5/64,5/64 3/16 rings. got my rings from ta performance and i asked tech to make sure of this fact. readind alot of stuff on here and just seems like i am getting in over my head here alittle. just dont want to have to tear this sucker down after i get it running because the rings wont seat. all my machine work was done by automotive machine and performance in phillpot ky. by mike and the boys.
    70 stg.1
    464 C.I.TA PERF. 413 CAM,ROSS FORGED RACING PISTONS,11-1 COMPRESSION, SP1 INTAKE WITH 850 DOUBLE PUMPER SPEED DEMON, MSD6AL WITH DIAL REV LIMITER,BILLET DIST AND SUPER CONDUCTOR WIRES, M/T SUPER COMP. HEADERS
    STREET STRIP PORTED IRON HEADS
    ACC BOSS HOG 3500 STALL 12 bolt 3:42
    http://www.youtube.com/watch?v=1PTn9PsPsLw

  5. #5
    Join Date
    Dec 2008
    Location
    Dayton TN. halfway between Chattanooga and Knoxville TN.
    Posts
    252

    Default Re: cast or chrome molly rings

    Personally I like the cast rings. Thats what I will be using on my new build up. They seal very fast and work well.... or always have for me. I've used them on several motors (Chevies, Fords, and 1 Buick). Even motors that I ran nitrous on with no problems.
    I've heard of cast rings breaking from abuse but I've never had it happen and I dont know of anyone that has had it happen.
    I think that you'll be fine.... lets see what the other guys say on here.
    Chime in fellows!
    Jim

  6. #6
    Join Date
    May 2002
    Location
    the Seasonally Frozen Wastelands
    Posts
    2,346

    Default Re: cast or chrome molly rings

    I've heard of chrome rings; they're useful when the engine is going to ingest a lot of dirt. 'Course, then the cylinder walls wear out instead of the rings.

    I've heard of moly-filled rings, they're useful for the other 99% of engines.

    But WHO makes chrome-moly rings, and does that describe the ring overlay material, or is it the kind of steel used to make the rings from, like a chromoly steel roll cage???

    http://en.wikipedia.org/wiki/41xx_steel

  7. #7
    Join Date
    Jan 2005
    Location
    Biloxi MS.
    Posts
    674

    Default Re: cast or chrome molly rings

    Quote Originally Posted by NitrousJim View Post
    Personally I like the cast rings. Thats what I will be using on my new build up. They seal very fast and work well.... or always have for me. I've used them on several motors (Chevies, Fords, and 1 Buick). Even motors that I ran nitrous on with no problems.
    I've heard of cast rings breaking from abuse but I've never had it happen and I dont know of anyone that has had it happen.
    I think that you'll be fine.... lets see what the other guys say on here.
    Chime in fellows!
    Jim
    I've heard Nitrous and Molley Rings don't work well together ? Is this true ?
    Richard Davis

  8. #8
    Join Date
    Sep 2004
    Location
    Michigan, USA
    Posts
    14,889

    Default Re: cast or chrome molly rings

    There's been confusion about ring material for decades, now. I'm also not up to speed these days, but here's the lowdown as I understood it:

    Cast iron, uncoated rings are typical stock replacements.

    Cast iron, chrome face plated rings are/were used for more durability in severe applications, like circle track engines...the chrome face is harder, but was also more difficult to seat (break in).

    Cast iron, molybdenum face coated rings are the more modern choice, able to handle high heat and aren't too difficult to seat.

    Unless something new has happened, there is no such thing as a "chrome moly" piston ring. They are all cast iron with or without various platings/coatings.

    Can anyone else help?

    Devon
    Fuel & Brake Systems Engineer
    "I can live with doubt and uncertainty and not knowing. I think it's much more interesting to live not knowing than to have answers which might be wrong." - Feynman
    "Good data is precious. The problem I have is when some damned fool fails to use it properly." - Slingerland

  9. #9
    Join Date
    Aug 2002
    Location
    ELBERFELD INDIANA
    Posts
    141

    Default Re: cast or chrome molly rings

    when i got my rings from ta performance it says moly on box. but receipt from ta says chrome moly rings. they are hastings rings. does not say anything about chrome on box just moly
    70 stg.1
    464 C.I.TA PERF. 413 CAM,ROSS FORGED RACING PISTONS,11-1 COMPRESSION, SP1 INTAKE WITH 850 DOUBLE PUMPER SPEED DEMON, MSD6AL WITH DIAL REV LIMITER,BILLET DIST AND SUPER CONDUCTOR WIRES, M/T SUPER COMP. HEADERS
    STREET STRIP PORTED IRON HEADS
    ACC BOSS HOG 3500 STALL 12 bolt 3:42
    http://www.youtube.com/watch?v=1PTn9PsPsLw

  10. #10
    Join Date
    Feb 2002
    Location
    Pine City, MN
    Posts
    8,015

    Default Re: cast or chrome molly rings

    While there are steel rings out there, often used for the top rings in turbo diesel applications, there are no automotive rings made of any type of chromemoly material.

    I do believe the terminology came from the old chrome ring sets. The top ring would be ductile iron coated with chromium, the second ring would be ductile iron coated with Moly.

    Thus a chrome-Moly ring set.

    As was stated, chromium facing as a ring face coating went out of favor many years ago.

    Today we really have Three choices choices for stock replacement and moderate performance.

    Cast replacement ring set
    Moly Ring set
    Plasma Moly Ring set

    A cast ring set is just that.. basically uncoated grey cast iron. These are inexpensive sets and work well with cast iron cylinder walls, and stock type builds.

    The downside of a cast ring is it's somewhat brittle. Easy to break when installing on the piston or when putting the piston in the bore. Also, they can break in use, in severe conditions such as detonation, or with real high rpm and cylinder pressure, such as a supercharger or turbo application.

    The top and second compression rings are plain cast iron.

    The next choice is Moly.

    Moly rings are a combination of compression ring materials.

    The top compression ring is made of ductile iron, commonly known as nodular iron. This material is not at all brittle. You can bend a ductile iron ring into a figure 8 and it won't break. The downside of ductile iron is that it's not real compatible to cast iron cylinders. It has to have a face coating, most often some type of moly.

    The Second ring in a moly ring set is often a plain, uncoated cast iron ring.

    The Third Choice is Plasma Moly

    Plasma moly rings are rings that have the moly deposited on the ductile top ring face with a plasma process. These rings break in quickly, and are very resistant to the abusive life of a top compression ring, in a modern high performance engine.

    Once again the second ring is a plain cast iron ring in these sets.

    _____________


    There are a lot of new technologies with rings these days, mostly concentrated on reducing their physical size, and therefore their friction, but those rings are beyond the scope of this discussion.

    For a little more money, I am a fan of a ductile iron top compression ring in most of the builds I do here.

    Stock type and moderate performance builds get Moly rings, and more performance oriented engine with the thinner rings get Plasma Moly sets.

    So, for the original poster, if you have a moly ring set, there this is no reason you can't use it. As was stated, stay away from Chrome rings, but you would probably be hard pressed to find a set of those today.

    But check with your machinist. Cast rings want a rougher cylinder wall finish, typically a 280 grit stone.

    Moly face rings should be used with a 400 grit stone finish on the cylinder walls.

    Matching the Ring type to the cylinder wall finish, and obtaining the proper end gap, is the most important concern in your buildup.

    Hope that helps

    JW
    Owner/operator

    Tri-Shield Performance
    Jim Weise
    Founder/Owner
    V-8 Buick.com
    320-629-8999 shop or 612-532-2207 cel

    Most folks are about as happy as they make up their minds to be.
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    16th president of US (1809 - 1865)

 

 

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