Ring Gap on JE
- Thread starter bobq31
- Start date
I feel I can give you a quality answer to this, the rule of thumb that I have generally used is .004 for every inch of bore. 81mm stock Hayabusa bore = 3.19 inches which would give an end gap of .01275 or .013 end gap. Considering the heat seen I would feel comfortable with an end gap of .016 on the top ring and an end gap of .020 - .022 on the second ring. On the second ring especially at the piston speeds we are talking about can build pressure between it and the top ring which is a contributor to ring flutter. So final answer I am smarter than a fifth grader is,
.016 top and .021 on the second ring,
Also to answer the second part if the end gap is to tight the ring will bind and scar the bore, to big and you will increase blowby however, the second option is better than the first. Hope this helps! Lets see who agree and disagrees
"O"
.016 top and .021 on the second ring,
Also to answer the second part if the end gap is to tight the ring will bind and scar the bore, to big and you will increase blowby however, the second option is better than the first. Hope this helps! Lets see who agree and disagrees
"O"
What he said 
:stupid:
:stupid:So a guy that is biulding 900hp civic's in my neightborhood gave me a formula that he gets from this wiseco website.
Ring Gap Table Instructions
1. This table is in inches. If you are measuring your bore in millimeters, you will need to convert to inches by dividing your bore size by 25.4.
2. Multiply your inch bore size by the “Bore x” column for your application to determine the end gap.
Example: For the top ring of an ATV with a 4.0” bore, multiply 4.0 X .004 = .016
Application
Top Ring 2nd Ring
Bore x Bore x
Dirt / ATV / Snow / PWC
.0040” .0050”
High-Performance Street / Strip
.0045” .0055”
Street-Moderate Turbo / Nitrous
.0050” .0055”
Late Model Stock
.0050” .0055”
Circle Track/Drag Race
.0055” .0060”
Blown Race Only
.0065” .0070”
Nitrous Race Only
.0070” .0075
Ring Gap Table Instructions
1. This table is in inches. If you are measuring your bore in millimeters, you will need to convert to inches by dividing your bore size by 25.4.
2. Multiply your inch bore size by the “Bore x” column for your application to determine the end gap.
Example: For the top ring of an ATV with a 4.0” bore, multiply 4.0 X .004 = .016
Application
Top Ring 2nd Ring
Bore x Bore x
Dirt / ATV / Snow / PWC
.0040” .0050”
High-Performance Street / Strip
.0045” .0055”
Street-Moderate Turbo / Nitrous
.0050” .0055”
Late Model Stock
.0050” .0055”
Circle Track/Drag Race
.0055” .0060”
Blown Race Only
.0065” .0070”
Nitrous Race Only
.0070” .0075
Okay so these numbers are for a stock busa not one trying to run somewhere in the area of 15psi? not trying to be combative however how is this different or more accurate? just trying to make sure, also not a 900hp civic, if 900 hp 1.8 liter the end gap because of required cylinder pressure is much different. Just trying to keep things simple. I work as a performance engine instructor and the requirement for something such as this are apples and oranges. Small Block Chevy at 900 hp okay, with a bucket full of money perhaps, however a civic is it tangeble yes, with five buckets full of money and a rebuild every other race. Feelings? I have been a member of the forum for some time and limit my responses because I use it primarily for Ideas however since I started a response I now feel it necissary to continue. I welcome your feedback, talk to you soon,
"O"
"O"
turbobusa2000
Registered
Just as a note. The service limit for stock busa is .020 inch. Thats top and bottom. Im running around 18 psi on the street and I filed mine to .007 per inch. Keep in mind also that from the street to the blown race recommendations there is only a 3 thousandth of an inch difference. I went through the same thing this past summer.
Hey "O", I think you might have taken my words as a little combative. I didn't mean it in that way. I only refered to Courtney Green's civic because it's pretty close to the engine I'm running. Busa is a 1.3 liter inline 4, His CRX is a 1.8 liter inline 4. So I trust his word because he and is crew's cars are all amazing. I came on here to ask because the fact remains, I'm working on a motorcycle he's in a car. He's running a little more boost than I plan on but he doesn't run an icebox which I will be doing. Just looking for as much good input as I can get.
No I didn't take it like that I was afraid you would take it that way from me, but since where okay. The real truth is that the directions have the best info on those specific rings, each manufacture makes them with different metals and percentages which means they each have a unique expansion rate. I didn't even relize actually that response was you I just thought is was someone else chiming in perhaps I was a little defensive. Wether you use a high mechanical compression ratio, Nitrous, Turbocharger or Supercharger you are working for the same thing, cylinder pressure. With an increase in pressure there is an increase in temperature, also your power comes from burning fuel, not from the N2O or Turbo they let you burn more fuel the energy of fuel is measured in thermal units so the more you burn more heat. If this was my engine and there where no directions I would set the gaps as I said in the first response if you look at those numbers provided from the site you supplied they where close. In any event good luck lets see some pics and updates, trying to save my pennies right now to take mine apart talk to you later,
"O"
"O"
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