Ring gap help !! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

ChiTownJDM · 06-26-2017, 04:41 AM

Okay , so this is my first time gapping rings and I need a little help!

Piston - CP 87mm 8:5:1 comp
rods - BC rods

So , cp recomends on the sheet .0035 gap on the rings. But I am turbo, so doesn't this mean I need to open them up more? . I was reading and saw online

Sport compact turbo/notrious 450+

Oil rings - .015 - .050
Top Ring - .0050 - .0055
Bott ring - .0055 - .0060

Those are the gaps I should use? What's this inch per bore I keep reading about ? Cause I'm 87mm not 86mm so +1mm bore.

hanzbrady · 06-26-2017, 06:26 AM

Follow CP's sheet, they know what they're doing. Those ring gaps you listed are massive so unless you're building a race only engine that you're expecting to get super hot I wouldn't use those.

I personally did something along the lines of

.022 top
.024 bottom

on my personal car.

ChiTownJDM · 06-26-2017, 08:17 AM

Quote:

Originally Posted by hanzbrady

Follow CP's sheet, they know what they're doing. Those ring gaps you listed are massive so unless you're building a race only engine that you're expecting to get super hot I wouldn't use those.

I personally did something along the lines of

.022 top
.024 bottom

on my personal car.

What kinda power? My motor is fully built,. Building the car for drifting up the motor is over kill.

hanzbrady · 06-26-2017, 10:23 AM

Quote:

Originally Posted by ChiTownJDM

What kinda power? My motor is fully built,. Building the car for drifting up the motor is over kill.

My motor is set up for about 500hp, but even on Dave Briggs's SR we never got into the .030's as far as ring gap is concerned. The gaps you listed is along the lines of1000hp alcohol no coolant drag engine builds.

KAT-PWR · 06-26-2017, 10:56 AM

My engine that's been in car boosted for 30k miles has .018, .020.
300-400whp forever 5% leak down

My high horse power spare I believe is .02, .022 (600hp goal)

bardabe · 06-26-2017, 11:56 AM

CP reccomends the following.

"SPORT COMPACT: Turbo/Nitrous applications to 450 - 750hp

Top Ring = .0050 - .0055
Second Ring = .0055 - .0060
Oil Ring – Actual Gap = .015 - .050"

these measurements are per inch, so to determine your ring end gap you'll have to take a dial bore gauge. measure the exact bore of each of your cylinders and then multiply by said number. so a close example would be

86mm = 3.3858"

3.3858 x 0.0050 = 0.0169" of piston ring end gap on the tight side or
3.3858 x 0.0055 = 0.0186" of piston ring gap on the loose side.

everyone has their own preference of ring end gap, I just wanted to clear that up for you so that you don't run a massive gap and ruin your build.

ChiTownJDM · 06-27-2017, 12:29 AM

You guys rock !! Thank you! I ended up doing
.018 Top ring,
.023 Bottom ring .
.015 oil rings.

Thank y'all for being so helpful!!!

jedi03 · 06-27-2017, 03:35 PM

I followed cp numbers to the t...no issues on daily driven vehicle!

06-26-2017, 04:41 AM	#1
ChiTownJDM Join Date: Apr 2014 Location: chicago Age: 28 Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	Ring gap help !! Okay , so this is my first time gapping rings and I need a little help! Piston - CP 87mm 8:5:1 comp rods - BC rods So , cp recomends on the sheet .0035 gap on the rings. But I am turbo, so doesn't this mean I need to open them up more? . I was reading and saw online Sport compact turbo/notrious 450+ Oil rings - .015 - .050 Top Ring - .0050 - .0055 Bott ring - .0055 - .0060 Those are the gaps I should use? What's this inch per bore I keep reading about ? Cause I'm 87mm not 86mm so +1mm bore.

06-26-2017, 06:26 AM	#2
hanzbrady Zilvia FREAK! Join Date: Apr 2015 Location: Floriduh Posts: 1,166 Trader Rating: (4) Feedback Score: 4 reviews	Follow CP's sheet, they know what they're doing. Those ring gaps you listed are massive so unless you're building a race only engine that you're expecting to get super hot I wouldn't use those. I personally did something along the lines of .022 top .024 bottom on my personal car. __________________ [email protected]

06-26-2017, 10:56 AM	#5
KAT-PWR Nissanaholic! Join Date: Dec 2011 Location: US Posts: 2,040 Trader Rating: (11) Rides Gallery: KAT-PWR Feedback Score: 11 reviews	My engine that's been in car boosted for 30k miles has .018, .020. 300-400whp forever 5% leak down My high horse power spare I believe is .02, .022 (600hp goal) __________________ MRP Manufacturing

06-26-2017, 11:56 AM	#6
bardabe Post Whore! Join Date: Aug 2005 Location: SoCal Age: 34 Posts: 4,719 Trader Rating: (10) Rides Gallery: bardabe Feedback Score: 10 reviews	CP reccomends the following. "SPORT COMPACT: Turbo/Nitrous applications to 450 - 750hp Top Ring = .0050 - .0055 Second Ring = .0055 - .0060 Oil Ring – Actual Gap = .015 - .050" these measurements are per inch, so to determine your ring end gap you'll have to take a dial bore gauge. measure the exact bore of each of your cylinders and then multiply by said number. so a close example would be 86mm = 3.3858" 3.3858 x 0.0050 = 0.0169" of piston ring end gap on the tight side or 3.3858 x 0.0055 = 0.0186" of piston ring gap on the loose side. everyone has their own preference of ring end gap, I just wanted to clear that up for you so that you don't run a massive gap and ruin your build. __________________ Review Thread

06-27-2017, 12:29 AM	#7
ChiTownJDM Join Date: Apr 2014 Location: chicago Age: 28 Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	You guys rock !! Thank you! I ended up doing .018 Top ring, .023 Bottom ring . .015 oil rings. Thank y'all for being so helpful!!!

06-27-2017, 03:35 PM	#8
jedi03 Nissanaholic! Join Date: Jul 2008 Location: albuquerque Posts: 1,836 Trader Rating: (8) Feedback Score: 8 reviews	I followed cp numbers to the t...no issues on daily driven vehicle!