2nd gapless ring

Discussion in 'PSI Superchargers Tech Questions' started by wildride boy, Jan 9, 2006.

  1. wildride boy

    wildride boy Top Sportsman Racer

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    Does somebody had problem using gapless second ring on alky blown BBC.
    Thanks
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    In tests by several piston ring companies the gapless second rings caused the top ring to flutter and not seal correctly while under load. You can get some impressive leakdown rates from them with the motor not running. My recommendation is to stay away from them.
     
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  3. TOL

    TOL Active Member

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    Has anyone tried the new gapless top groove rings?........
     
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    Last edited: Jan 10, 2006
  4. Alkydrag

    Alkydrag Sr. Dragster

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    Mike your right. The use of a gapless ring will cause the top ring to unseat from the piston and cylinder wall, losing compression and power.This happens because the 2nd ring's function is oil control and it cannot seal compression on it's own. If you look at the way a gapless ring is made, they actually machine half the ring life away to accept the rail that makes it gapless. Leakdown figures are great, if your racing leakdown gauges. We've run cosistant 5.70's at 250MPH with a motor leaking at 15%. If gapless rings are so good, why don't the OEM's use them? The OEM's are actually opening up the 2nd ring gap to 1 to 1 1/2 times the top ring gap.
    Here's how I got turned off by gapless rings. One night I was putting a fresh motor together. I always used cast iron taper faced 2nd's. All I could find was some gapless rings. I installed them. Motor in the rails, hat wide open and 48 volts. 150 PSI is all I had, normally I want 190PSI. After bumping the cam timing 8 degrees, I finally had 165PSI. Pulled no. 1 out, put on a junk 2nd ring I found in the trash, hat wide open and 48 volts. Wow, 240 PSI. Put the cam back where I started from, now I had 190PSI. Now I'm really mad because I have to take the motor all apart now. That's my story and I'm sticking to it.
     
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  5. Mike Canter

    Mike Canter Top Dragster
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    I agree and yes the new trend is to open up the 2 nd ring gap to be the same as the 1st ring gap. On the Hellfire rings for both nitrous and blower they want 1st and 2nd ring gaps the same at .007 times the bore diameter.
     
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  6. wildride boy

    wildride boy Top Sportsman Racer

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    Thanks guys for your quick response , i appreciate
     
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  7. Slayer

    Slayer Member

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    Does this problem also apply to a dykes style top ring?
     
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  8. Alkydrag

    Alkydrag Sr. Dragster

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    It doesn't matter what top ring style you run. Keep this in mind. When a ring is machined to accept the rail to make it "Gapless", you machine cast iron or ductile iron away and replace it with steel, thus making the ring heavier. The heavier the ring is, the earlier in RPM ring flutter occurs.
     
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  9. Frank Intini

    Frank Intini Jr. Dragster

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    we used the 2 peice gapless 2nd rings and had no end of trouble with our SBC TAD and the thing used to pressurize the crankcase big time and then push oil out of the block to manifold seals, nearly tipped the car over several times let alone swapping lanes and clean up crews preparing when they saw us coming.
    Until one night putting the eng together i broke one and all i had was C&A ZGS set so put them in and problem gone.
    Now at 9800 and 54lbs boost we only have 4lbs positive pressure in the crankcase so weve stuck with C&A since.
     
    #9
  10. TOL

    TOL Active Member

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    Has anyone tried high alky boost with the 2-part top rings that are now available? I'd be curious about any feedback on those.........

    Thanks.
     
    #10
    Last edited: Jan 21, 2006
  11. Slayer

    Slayer Member

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    Sorry, I must be misunderstanding something here. Aren't the C&A ZGS (Zero Gap) rings gapless? Is there a difference between the single gap (ie. C&A) and two piece ring? I tried the C&A last year and found way too much pressure in the pan (and everywhere else ). What is the best 2nd ring to use? Thanks for the help.
     
    #11
  12. Mike Canter

    Mike Canter Top Dragster
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    The pressure in the pan was caused by the ZGS rings fluttering and allowing blowby. Like I said they have impressive leakdown figures but that is not the car going down the track.
     
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  13. Raymond Raaymakers

    Raymond Raaymakers New Member

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    So is the ideal set up a dykes top ring with a reverse taper 2nd ring?

    Cheers Ray
     
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  14. rpmhiperf

    rpmhiperf Blown Alcohol

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    ringer!

    And a high tension oil ring.
     
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