3-ring versus 4-ring pistons~308

dougson
dougson Senior Contributor
edited November -1 in HUDSON
Are there suppliers of 3-ring pistons for the 308? Is there a debate concerning 3-ring versus 4-ring? My basic understanding is that modern technology in producing pistons eliminates the fourth ring, it's no longer required.

Comments

  • Park_W
    Park_W Senior Contributor
    I got the same advice from a friend who used to be at Hastings and was a ring designer. I've been running my Hornet with 3 modern rings and the lower groove empty for about 25,000 miles now. Nary a problem of oil consumption, smoking, etc. One interesting note: Hastings and maybe others make a type of ring referred to as "barrel-faced." The outer surface of the ring is slightly convex, which has two advantages: takes less pressure to maintain a good seal, thus less cylinder wear; and if there IS cylinder wear, the convex face fits and seals better in the worn part of the bore. Win-win.
  • dougson
    dougson Senior Contributor
    Thanks Park W. I went on the Hastings website and they do not list the 308 6 (at least anymore) in their applications. However, the size I need (diameter) for a 308 + .030 (3.84) is listed and several types of rings are listed as well, including the barrel face. Is this what you used?
  • Park_W
    Park_W Senior Contributor
    Yes, I just ordered them based on the groove dimensions and bore size, and the two compression rings were the barrel-face type.
  • Browniepetersen
    Browniepetersen Senior Contributor
    I machined my own pistons and used three slotted racing rings. I recommend it.... Also, I expect that you guessed I did not use "pined" pistons or rings...
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