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  1. #1
    RXP 260 X Short Course Veteran RXP244's Avatar
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    Riva Pistons- Yes or No?

    Can anybody tell me what the weight difference is between the new 4tec replacement Riva Pro pistons (in store) and the OE RXP215 pistons. If I replace the stock pistons with the Riva, will I have to have the crank assembly balanced?

    Thanks in advance.


  2. #2

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    I think the piston and pin assy. came in about 100g lighter. I put them strait in, I made no mods to balance.

    100% successful, have not drained 1 drop out of my catch can since I put them in. Zero Gas in Oil, and I am 100% satisfied. This is a CC race application 25 - 30psi boost turbocharged, and I have about 40 hours on them now running the engine at and over 9000rpm.

    They worked hard on this one to offer an affordable product that addresses all of the issues I was having with the OEM ring package.

  3. #3
    RXP 260 X Short Course Veteran RXP244's Avatar
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    Riva Pistons

    I know what you mean. They look like a nice bit of engineering. I think my OE rings have suffered from running a bit on the lean side. Pistons have! Been running AFR 12.4 WOT for long periods. 70 hours on them though. I am looking for the most cost effective way of giving the engine a freshen up, but also perhaps a bit stronger, for a bit more boost! If I put a set of Carillos in there also, it would deffinately need a balance. But I would have thought that 100g dif in piston, it would need some sort of balance. Please, correct me if I'm wrong?

  4. #4
    West Texas RXP skoepp's Avatar
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    All reports sound good.
    I am having doubts right now as i am about to put my block back together. I went (mahle) OEM 1 size over and thinking i should have gone with the riva pistons.

    What compresion ratio are you guys running?

  5. #5
    RXP 260 X Short Course Veteran RXP244's Avatar
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    I am currently just running stock internals with a block guard. So compression is standard 8.4 I suppose. But Louis is running some big boost on std comp??. I don't see a need to lower it from std. Louis?

  6. #6
    West Texas RXP skoepp's Avatar
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    Quote Originally Posted by RXP244 View Post
    I am currently just running stock internals with a block guard. So compression is standard 8.4 I suppose. But Louis is running some big boost on std comp??. I don't see a need to lower it from std. Louis?
    K, thanks, I am going back all stock iternals but pretty much all new. I was running a block gaurd and the top reworked.

    What kinda fuel you guys running???

  7. #7
    RXP 260 X Short Course Veteran RXP244's Avatar
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    Crank balancing with Riva Pistons

    Has anybody else used the new Riva pistons without re-balancing.

    Anybody know what Riva recommends. I should ask them!

  8. #8
    RXP 260 X Short Course Veteran RXP244's Avatar
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    Quote Originally Posted by skoepp View Post
    What kinda fuel you guys running???
    Pump gas here in good old NZ. Mobil Synergy 8000 or BP 98. What evers available close to venue.

  9. #9

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    Quote Originally Posted by RXP244 View Post
    I am currently just running stock internals with a block guard. So compression is standard 8.4 I suppose. But Louis is running some big boost on std comp??. I don't see a need to lower it from std. Louis?
    I am running higher than stock compression. The Riva Std piston is actually 2cc more combustion chamber volume, and I am running with 1 layer removed from the stock head gasket (uncut head). I calculate 8.55:1

    I run a 50:50 mixture of sunoco supreme 110 and 93 pump fuel with zero issues. I target 100 octane, and I like the lead for valve seat and guide wear. It is also cheaper to blend, then to but strait 100 or 104.

  10. #10

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    As for balance, I am not 100% sure how to answer this one correctly. I have put a few motors together with pistons and carillo rods, and have not done anything with balance. They don't vibrate, and they have been very reliable. I am still running stock rods with stock bolts with no problems in my race engine, but I am having some rods made right now that will change a few things.

    As for the balance, it is a tricky motor to balance 100% a counter balanced 3 cylinder !! Like I said, they run smooth, and I have seen zero odd bearing wear. With turbo you also have the advantage of the ability to use very good oils. I use the Mobil 1 racing oils like a 10-30 or in the really hot months 0-30 but I do not think you can run these with a super charger or the clutches will fail sooner.

    If anyone has any other thoughts on balancing I would love to hear it. As for me, I have done nothing so far.

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