302 Cylinder ring seating

Discussion in 'General Automotive Questions' started by Green79, Dec 27, 2020.

  1. Green79

    Green79 In First Gear

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    So I replaced one of the pistons (new piston head and new rings) in my 79 GT (its running a 72 302) ,, and I didn't hit the bore with a hone before putting it all back together. Well it runs but I am pretty sure not hitting the bore with a hone is biting me in the ass because I have some pretty serious blow-by now.. except if I dribble a little trans fluid into the plug hole. If I do that (and purge the excess fluid out of it) and put the plug back in and start it up it has like zero blow by.. until I try to spin the tires then I am back to blowing out of the pcv like crazy. So I figure that is from the new rings on the glazed cylinder.. So the question is, after reading some other places on the internet talking about all sorts of solutions (including the bon-ami ones) I am trying to decide if I really have to tear it back down, get a hone coming from amazon and do it or if anybody will tell me that they will eventually seat permanently and it will be ok. I really kinda don't want to pull it back apart again, and it's cold out. Anybody? (should I just suck up?) Thanks.
     
  2. pmrphil

    pmrphil In Maximum Overdrive GOLD MEMBER

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    Sorry to say, but they won't seat by themselves. I've heard of the bon-ami trick, but I have zero knowledge if it really can work or if it's an old wive's tale.
     
  3. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Bon Ami was (reluctantly) used by Chevrolet dealers with the then-new 1955 265 CID V8s. The metallurgical formulations in both the cast iron and rings prevented the rings from breaking in and properly sealing the cylinders, so the dealer mechs used Bon Ami, blown into a powder into the carb, while the engine was running at, IIRC, 2000 RPM.
     
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  4. 65restomod

    65restomod In Overdrive BRONZE MEMBER

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    I have to ask
    Were the ring gaps spaced far enough away from each other?
    if so the choice to deglaze is imminent
    Either way head has to come off
     
  5. Hillbilly

    Hillbilly In Maximum Overdrive

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    Andy, your age is showing to know about that BonAmi trick. An Aunt in Colorado was freaked out when she saw the dealer dump all that dust into her new 55, but it worked.
     
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  6. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    And the irony in its use? Their tagline: "Hasn't scratched yet.":D
     
  7. Green79

    Green79 In First Gear

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    @65restomod ya, I think they were far enough away from each other .. 10 & 2 or something like that I think... if not further. I wouldn't think a dribble of trans fluid would fix stacked gaps but I could be wrong. First time doing this sort of engine internal work. So I guess next question would be in re to hone, I'm leaning towards a 3 stone setup.. looks like it's a better value since it would be usable on a variety of bores unlike a ball hone. Convince me otherwise. Thanks for the replies gents.
     
  8. pmrphil

    pmrphil In Maximum Overdrive GOLD MEMBER

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    For a new bore, three stone hones are fine, for a used bore, a ball hone (around a 280 grit) is a MUCH better idea. And another set of rings for the hole you're honing.
     
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  9. beerbelly

    beerbelly In Maximum Overdrive SILVER MEMBER

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    Here's a video of a quick rebuild, with the ball honing process starting at 9:45. He's using moly rings, so he goes a step further to 400 grit.

     
  10. Green79

    Green79 In First Gear

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    Thanks, I have watched this one before. I'm a pretty big fan of ole Derrick at VGG,
     
  11. beerbelly

    beerbelly In Maximum Overdrive SILVER MEMBER

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    Yeah, me too. The guy plays like he's a clown, but he knows his stuff.
     
  12. Clark

    Clark In Maximum Overdrive

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    I watched my Dad do the Bon Ami treatment when desperate - a last minute resort - but it was always a failure. This, as I recall, was with a new breed of chrome TRW rings that never would properly seat.

    Hmmm, seemed like Sealed Power had the first chrome plated rings that worked well. Am I right Hillbilly?
     
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  13. 72GTVA

    72GTVA Administrator Staff Member

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    What oil are you using, specifically, is it a synthetic, or an additive enriched oil such as Castrol GTX (etc.), or a non-detergent automotive oil?
     
  14. Hillbilly

    Hillbilly In Maximum Overdrive

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    Clark, you are dead nuts on the money about those chrome rings. A cousin rebuilt his Jeep six cylinder using a set of nos TRW rings and got terribly disappointed. Never did seat those rings leading him to teardown again after pouring the oil thru it for a year. I convinced him to try the Sealed Power rings after he did a very light pass with a ball hone. New rings seated within a week and still working great many years later. His engine had a super hard block still on the original bore size with no ring groove at the top of the cylinders. I still don't trust the TRW offerings. And Dan's point is true, synthetic oil is great, just not in a fresh built engine.
     
  15. Green79

    Green79 In First Gear

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    If @72GTVA is asking me, I think all that is in right now is the cheapest o'reilly house brand 10w30, I haven't changed it out to be anything I would leave in long term and actually drive on for any extended period of time.

    I did have "Mr. Brown" stop by this morning with a fresh amazon package from Brush Research.
     
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  16. 6delta

    6delta In Fourth Gear

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    A bit late to mention this as you have probably started to do whatever you were going to do, but did you check the compression?
     

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