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Old 06-25-2019, 12:59 AM   #1
nucci
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Default Piston ring gaps - new Manley too loose?

99.55mm Manley 2618 pistons and included rings, piston to wall .0035

Out of the box they end up with .023 top, .025 second gaps on cyls 1/2 and .024 top, .026 second on cyls 3/4.

Too loose? I had advice to set them at .020/.024.

Calling Manley in the AM, curious what you guys think.
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Old 06-25-2019, 11:56 AM   #2
nucci
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Manley tech referred me to Total Seal tech.

He said if anything hed run looser gaps than what I have already.

Im gonna leave them and send it
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Old 06-25-2019, 03:52 PM   #3
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how much power are you planning to make?
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Old 06-25-2019, 04:14 PM   #4
nucci
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350-420 wheel on 21-23psi pump, built to later take 500+ and 30psi on E or race gas. Open deck but real rods, ARP2000 studs, JE Proseal Athena head gaskets.

Edit: measurements sans torque plates

Last edited by nucci; 06-25-2019 at 07:48 PM.
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Old 06-25-2019, 10:03 PM   #5
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A bunch of searching around here is leading me to believe that a .018 top ring would be a lot better idea, question is how much ...

May be ordering 99.75 rings tomorrow.
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Old 06-25-2019, 10:49 PM   #6
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Quote:
Originally Posted by nucci View Post
A bunch of searching around here is leading me to believe that a .018 top ring would be a lot better idea, question is how much ...

May be ordering 99.75 rings tomorrow.
I agree with this. I prefer to do second ring a little bigger.
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Old 06-25-2019, 11:20 PM   #7
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Big difference between E85 and gasoline style fuels/race gas. I think with the E85 a little tighter is fine because of the residual cooling,

but with race/gasoline fuels it will get hotter (piston will expand more) and need a larger gap, given the same output
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Old 06-25-2019, 11:37 PM   #8
nucci
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Decision made - oil rails are .033 to .040, way too big. Getting 99.75 rings.

PSA: 99.55mm pistons are weird for rings
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Old 06-26-2019, 11:40 AM   #9
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Quote:
Originally Posted by Kingtal0n View Post
Big difference between E85 and gasoline style fuels/race gas. I think with the E85 a little tighter is fine because of the residual cooling,

but with race/gasoline fuels it will get hotter (piston will expand more) and need a larger gap, given the same output
i also agree with this.
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Old 06-27-2019, 08:04 AM   #10
Barge
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Makes it a bit tougher if you build a motor for flex fuel then I guess.
Well you'd probably either have to run with more blowby... or just make sure your gas tune is really turned down.
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Old 06-27-2019, 10:50 AM   #11
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So, just curious, what's a good range for ring gap using flex fuel and sub 450 whp? I was looking at CP's instructions and they're recommending .021 for the top and .023 for the bottom using the turbo sized gap formula.
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Old 06-27-2019, 11:46 AM   #12
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Originally Posted by Barge View Post
Makes it a bit tougher if you build a motor for flex fuel then I guess.
Well you'd probably either have to run with more blowby... or just make sure your gas tune is really turned down.
If I am doing one of our bespoke motors one of the questions I ask is what fuel they are going to be running. For example, if it's a dedicated track car that will only ever see e85 I will build it with tighter ring gaps and tighter PWC than I would if the car is going to be running 93.

Now, those measurements will also depend upon the power goals as well along with piston material and a bunch of other stuff.
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Old 06-02-2020, 07:04 PM   #13
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Quote:
Originally Posted by Turn in Concepts View Post
If I am doing one of our bespoke motors one of the questions I ask is what fuel they are going to be running. For example, if it's a dedicated track car that will only ever see e85 I will build it with tighter ring gaps and tighter PWC than I would if the car is going to be running 93.

Now, those measurements will also depend upon the power goals as well along with piston material and a bunch of other stuff.
Would you run a 0.018 top and 0.020 second ring on a daily driven motor on mostly e85?

Also, what's your thoughts and experience with Gap-less second ring?
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Old 06-03-2020, 12:47 PM   #14
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Quote:
Originally Posted by Fierysun View Post
Would you run a 0.018 top and 0.020 second ring on a daily driven motor on mostly e85?

Also, what's your thoughts and experience with Gap-less second ring?
How much power, and how much are you going to hammer on it?

If you're going to be sub-450 I would like to see something just a skoosh tighter on the rings, but honestly I wouldn't have a problem with .018, but do watch fuel dilution.

I have not played with the gapless second, but I have played with the gapless top on a Subaru. I REALLY liked it, BUT there's a couple of things. 1) Absolutely follow their gapping instructions (I think they spec .0065 per inch of bore - second guessing them my first time I tried it led to failure) and 2) my experience was in a race motor so I cannot tell you any results from long term use.
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Old 06-03-2020, 01:12 PM   #15
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I'm targeting 0.0196 and 0.0216 for gaps. which is what JE recommends.

450-500 whp on E85. high boost
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Old 06-03-2020, 01:44 PM   #16
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Quote:
Originally Posted by cboggess View Post
How much power, and how much are you going to hammer on it?

If you're going to be sub-450 I would like to see something just a skoosh tighter on the rings, but honestly I wouldn't have a problem with .018, but do watch fuel dilution.

I have not played with the gapless second, but I have played with the gapless top on a Subaru. I REALLY liked it, BUT there's a couple of things. 1) Absolutely follow their gapping instructions (I think they spec .0065 per inch of bore - second guessing them my first time I tried it led to failure) and 2) my experience was in a race motor so I cannot tell you any results from long term use.
How gap would you run for around 400whp?

What benefits do you see with running either/both gapless top and second ring?
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Old 06-03-2020, 07:21 PM   #17
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Quote:
Originally Posted by Fierysun View Post
How gap would you run for around 400whp?

What benefits do you see with running either/both gapless top and second ring?
.016 top, .018 second.

The compression and leakdown was absolutely awesome on the gapless top ring. Like amazingly so.

Sadly I believe that motor met it's demise with a broken valve spring... I can't remember which track that was at. I want to say it was Mid-ohio on that one. It was a number of years ago.
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