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[HD Street Performance]

I'm assuming no crush but measuring the thickness at the sealing ring my calipers indicated .060-.066 ish.

?shrug?


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Measure at the flat spot

[KC2GIW]

Measure at the flat spot

Should have googled harder


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[dnlpnd]

I'm assuming no crush but measuring the thickness at the sealing ring my calipers indicated .060-.066 ish.

Interesting.  If you are measuring the same way as the gasket manufactures, that is a really thick HG!  In any case, I will be going with the Cometic 0.030" HG.  I am also going to have a little taken off the stock CVO head AND/OR the 117 cylinder.  The question is how much?  The deck height (piston in the hole) is being assumed at -0.004" or -0.005".  Maybe 0.010" from HG, ~0.005" off cylinder, and 0.020" off head.  I've heard you can go up to 0.050" total without screwing up the intake alignment.  My builder will probably have to clay everything to make sure there are not any interferences.

dnlpnd

[HD Street Performance]

OK you got that covered then

[dnlpnd]

Interesting.  If you are measuring the same way as the gasket manufactures, that is a really thick HG!  In any case, I will be going with the Cometic 0.030" HG.  I am also going to have a little taken off the stock CVO head AND/OR the 117 cylinder.  The question is how much?  The deck height (piston in the hole) is being assumed at -0.004" or -0.005".  Maybe 0.010" from HG, ~0.005" off cylinder, and 0.020" off head.  I've heard you can go up to 0.050" total without screwing up the intake alignment.  My builder will probably have to clay everything to make sure there are not any interferences.

dnlpnd

I couldn't help myself.  My take away from this is going from a 0.040" thick HG to 0.030" thick HG bumps the compression ~0.2:1.  ie: 9.9:1 --> 10.1:1

Personally, I'd like to end up between 10.5:1 and 10.8:1.  So, besides the thinner HG, another ~0.020" off the head and cylinder would put me at ~10.6:1.  B-I-N-G-O

Let the comments begin. 

dnlpnd

[HD Street Performance]

I couldn't help myself.  My take away from this is going from a 0.040" thick HG to 0.030" thick HG bumps the compression ~0.2:1.  ie: 9.9:1 --> 10.1:1

Personally, I'd like to end up between 10.5:1 to 10.8:1.  So, besides the thinner HG, another ~0.020" off the head and cylinder would put me at ~10.6:1.  B-I-N-G-O

Let the comments begin. 

dnlpnd

You forgot one thing
If you do not touch the heads your analogy works but as soon as the seats are ground CCs increase and the heads then need more of a mill.
Not the way I will be approaching these builds. A small dome piston has no downside and then milling will be close to 0 and just equalizing cylinders. I am going that route
One other reason for the custom piston is I can set the valve reliefs in the proper places at the proper depth and at the proper radius for a slightly oversized valve. Adds versatility because there will be the guys that will want to run MVA heads or port the stockers in which case the 2.12 intake is a natural same as the MVA uses.

[dnlpnd]

You forgot one thing
If you do not touch the heads your analogy works but as soon as the seats are ground CCs increase and the heads then need more of a mill.
Not the way I will be approaching these builds. A small dome piston has no downside and then milling will be close to 0 and just equalizing cylinders. I am going that route
One other reason for the custom piston is I can set the valve reliefs in the proper places at the proper depth and at the proper radius for a slightly oversized valve. Adds versatility because there will be the guys that will want to run MVA heads or port the stockers in which case the 2.12 intake is a natural same as the MVA uses.

I hear you and do not disagree, but I plan to use the flat-top pistons that come with the kit.

dnlpnd

[HD Street Performance]

Your going A to B and in the end you can get there and have the same result except ~.050 comes off the heads and the valve reliefs will need a little opening. You have a good shop that does this all the time so should no big deal and the head shop will fix the intake flanges.

[Lever]

That's sucks.... my next question is can it be returned ? Or do bore it .010 over  if over size pistons are available

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[Ridgerunr]

In the other thread I mentioned some 4.060" bore cylinders had the same problem. If this is going to be the norm, a custom piston like what Don is offering would be the way to go. question now is, will 0.005 clean them up, or will it have to be 0.010 over!

[cvosjoe]

In the other thread I mentioned some 4.060" bore cylinders had the same problem. If this is going to be the norm, a custom piston like what Don is offering would be the way to go. question now is, will 0.005 clean them up, or will it have to be 0.010 over!

I'm going the custom piston way. Purchased the cylinders and they have already been shipped for fitment.

[GMR-PERFORMANCE]

https://www.dropbox.com/s/9bzttg6v3cko9oz/20160217_191950.mp4?dl=0   My 117 kit is out of round

I know the voice on that Video , you had them measured in AL correct ??

[MrSurly]

Possibly related, I've been wondering just how repeatable the measurements are, if you loosened/re-torqued the plates a couple of times. The assumption would be *very* repeatable... but is it really?

[HunterJ]

That's sucks.... my next question is can it be returned ? Or do bore it .010 over  if over size pistons are available

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I'd see about returning it before I'd  spend money fixing what should have been right to start with. Especially since these walls are thin, even if they are steel.

[HunterJ]

That's sucks.... my next question is can it be returned ? Or do bore it .010 over  if over size pistons are available

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I'd see about returning it before I'd  spend money fixing what should have been right to start with. Especially since these walls are thin, even if they are steel.