I'm running a 388 SBC stroker with 11.0-1 compression. We just yanked the motor to freshen it up, well I can't find chrome moly's to save my life i guess they stopped making them so I bought, what was suppose to be, plasma moly perfect circle rings. Well I get them and they are standard moly rings I'm trying to return them but would moly's be good to run or not. This motor see's light street use and the concessional track time.
There never has been chrome moly rings, at least in what you're looking for. Chrome moly is a heat treated steel, we're looking for iron rings, and even the max-effort steel rings I'm pretty sure don't use chrome moly steel but onto the next point...The only difference in moly and plasma moly rings is the application process of the molybdenum coating. According to many manufacturers the plasma moly process makes a much stronger coating that won't be as likely to flake off. Many believe that the word plasma moly goes hand-in-hand with a higher quality ductile iron ring material, I'm sure some manufacturers differ though. Usually a cheapo, plain moly coated ring will be cast and will be more brittle. The use of a moly coating is to promote quick ring-seating and to increase ring life so I say you go with the coating process that will stay on the longest! My opinion is to not skimp on the rings, it's usually only another $50-$60 for a higher quality metal and moly application process.
I use Speed Pro moly rings, usually about $100 a set and have had excellent life out of them. The 351C 2V had 2000 drag passes when it came apart for freshening and the ring seal was fine, bores looked really nice. 302 had 10 years of service , about 6 on the street and 4 on the drag strip (maybe 1500 passes or so) and it never had a problem with ring seal.
1967 Falcon 4 door - 351C1970 Mustang coupe - 351Chttp://raceabilene.com/kelly/hotrodOwner built, owner abused.
I run speed pro chrome plasma moly file fit rings. I love them to death. never had a problem about $100 for a set for my turbo'd windsor thats in my stang and I just built an olds 455 and they were basically the same price there too. brandon
Chrome plasma moly? That's even a new one yet!Speed Pro does not take an iron ring and put a chrome coating on it followed by a moly coating. I'm sure the moly wouldn't stick and there probably wouldn't be any advantage...
Gibs, we could really use you at HR too. As Gibs said, and depending on the specific application, there are other options other than material that should be considered.
Just here to help, Professional Automotive Technician, Engine Builder, and Ford guru.Bill Voorhees
I did not say that speed put a chrome and moly coating on an iron ringmy salesman at the pro-shop account through summit describes them as a "chrome plasma moly file fit" sorry for any misconceptions here. Just trying to help anyways check it out... great set of rings either way.here is a link of the ring description http://store.summitracing.com/partdetail.asp?autofilter=1&part=SLP%2DR934935&N=700+401105+115&autoview=skuTop Ring Material: Iron Top Ring Facing Material: Plasma-moly Second Ring Material: Iron Second Ring Facing Material: Cast iron Oil Ring Material: Chrome plated carbon steel Quantity: Sold as a set. Notes: Oil rings are chrome carbon steel scrapers with a stainless steel spacer ro uses and iron ring with chrome and moly coating.
Don't take any offense, we're just talking about terminology and semantics here as we both know what rings we're speaking of but I just can't help myself but to clarify...Chromoly refers to steel, usually a 4130/4140 alloy. We aren't dealing with steel compression rings here. Compression rings are typically iron and usually have a molybdenum (no chromium!) coating applied to them somehow. I am not so concerned with the metallurgy of the oil rings as it's rarely discussed. I think the most important considerations for the oil rings are the tension and friction that they produce. Obviously you can't ignore the alloy all together because then you would have oil rings in pieces but it's just rarely spoken of in the performance world.*** your summit part number doesn't work for me. May I ask why this top ring isn't listed as ductile iron? Usually that's what Speed Pro's higher quality top compression rings are listed as...
I did not search it as a particular part # application. I can ask about part #'s though if you like... I used to work for Red Redeker. NHRA mechanic of the year for 94-95 and tim wilkerson's crew chief for team NAPA when he won the national title. This was the best of all worlds in his opinion... he was a god of engine building. I figure he had forgotten more than I will ever know and if it worked for him it works for me. sometimes you just use what works for you. There is more than one way to skin a cat. I have built several big block olds motors with those rings and many small block fords including the turbo'd windsor that's in my mustang... with the aggressive tune the car makes near 800 rwhp... and is still street driven. I can't stand a high strung engine that smokes when you drive it but runs like a scalded dog when your foot is in it. lol let me know if you have any questions... I just wanted to give you a material break down for the example... that's all.
Plasma is a form of heatreatment for the rings.They are still chrome moly rings.chrome moly rings are ment to be(originally)used with a hard chrome bore,usually found in exotic engines.Yes they are more durable and stronger than standard.How ever will wear the cylinder bores quicker, than standard rings.Also take into account how much mileage the engine will see.