Advice on my piston ring end gap

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Jul 2, 2009 | 06:19 AM
  #1  
I read the Evans Tuning article on engine building and i bored my block to 81.5mm here are my gaps after cut

Top Rings- .020

Second Rings- .024

Oil Rings- .015

Im going forced induction. My question is, do i have to start over with new rings or will i be ok with these gaps? Thanks
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Jul 2, 2009 | 10:18 AM
  #2  
Re: Advice on my piston ring end gap
I HAVE ALREADY POSTED THIS USE THE SEARCH BUTTON THAT IS WHAT IT IS THERE FOR!!!!!

------------------------------------Top Ring---------------Second Ring--------------Oil Ring---------

Street/High Performance:---Bore X .0045/.005"---Bore X .005/.006"------Min .015"

Drag/Circle Track Racing:----Bore X .006"------------Bore X .0065/.007"----Min .015"

Nitrous/Turbo/SuperChrgd:-Bore X .0065/.007"----Bore X .007/.008"--------Min .015"


This Should be put in the FAQs...
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Jul 2, 2009 | 10:23 AM
  #3  
Re: Advice on my piston ring end gap
In case you can't do the math or are confused your gaps are all fine.
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Jul 2, 2009 | 01:44 PM
  #4  
Re: Advice on my piston ring end gap
thanks man, sorry i have been searching, i just didnt come across ur thread. After searching my results said that the min top should be .019 and second should be .023. Mine are .001 greater on each, i just wana make sure it wont cause blow by and smoking. Just wanted to make sure that gap isnt too wide.
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Jul 2, 2009 | 01:51 PM
  #5  
Re: Advice on my piston ring end gap
oh another question is there room for "error" like for top ring .019-.022, second ring .023-.025 etc. Is there a certain limit that is too wide?
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Jul 2, 2009 | 07:39 PM
  #6  
Re: Advice on my piston ring end gap
Quote: oh another question is there room for "error" like for top ring .019-.022, second ring .023-.025 etc. Is there a certain limit that is too wide?
Yes you can go too wide. I would not go out of the specifications listed above. If you go too wide you will not have good ring seal from expansion and will have very bad blow-by. A lot depends on what compression you are running or how much boost as to how much is too much. You can also have too little gap and cause the rings to come into contact and shatter then you most likely have a hand-grenaded motor.

I am not sure on a maximum or minimum, I just use the formulas and I don’t have any problems. If it is outside or inside the formula’s specifications then I get new rings.
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Jul 3, 2009 | 04:34 AM
  #7  
Re: Advice on my piston ring end gap
im not trying to sound like a noob but every time i use that formula i come up with a number that doesnt make sense. A number like 2.206 or something. Everything i search for on here i get a range to keep in like .019-.021 for top and add .004 to the top to get the second. so like my top was .020 and add .004 and get .024. Thats the way it was explaining on the Evans Tuning Build Thread found on here. So am i safe with those numbers?
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Jul 3, 2009 | 04:43 AM
  #8  
Re: Advice on my piston ring end gap
man the formula is easy

lets say your cylinder wall is standard bore. 81mm so conversion would yeild

3.1889" x .0065
to
3.1889 x .007

so specs are .020-.022 for the top ring for forced induction
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Jul 3, 2009 | 06:31 AM
  #9  
Re: Advice on my piston ring end gap
Let me try this again, double check me please.

81.5mm bore= 3.209

Top Ring 3.209 X 0.0065= 0.0208585 0r 0.020

Second Ring 3.209 X 0.0070= 0.022463 or 0.022

Oil Ring= 0.15 no gap
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