Jump to content
SAU Community

Recommended Posts

hey, im about to set my ring gap on my rb25 and would like some opinions from you guys. im using cp's with 40 thou over pistons. cp reccommend bore x 0.0065/0.007 for top ring, bore x 0.007/0.008 for 2nd and min. of 0.015 for oil.

my bore is 3.425'' so top works out at 0.023, 2nd at 0.0274.

is this suitable or is should i be running something smaller. thanks.

Link to comment
https://www.sau.com.au/forums/topic/239144-cp-ring-gap/
Share on other sites

umm, id take 5 thou of that. for both. there gaps are a little big for a street motor.. somwhere around 15 and 18 is fine.

correct...the ring gaps quoted by Elite are excessive to say the least.

i wont quote what ring gaps i use but some where around or near to whats quoted above

Link to comment
https://www.sau.com.au/forums/topic/239144-cp-ring-gap/#findComment-4179720
Share on other sites

correct...the ring gaps quoted by Elite are excessive to say the least.

i wont quote what ring gaps i use but some where around or near to whats quoted above

Great! so now you know more than the piston manufacturer. Congratulations.

I just hope this guy has the good sense to not listen to your comment and instead listen to the people who make the piston and rings.

But hey, I could be wrong. While you're at it, give him your rule of thumb on piston to bore clearances. We wouldn't want him making the mistake of using the piston manufacturers specs on that one.

Link to comment
https://www.sau.com.au/forums/topic/239144-cp-ring-gap/#findComment-4180288
Share on other sites

Run them where you/he likes...its your/his engine

ask my customers have they ever had a problem with an excessive breathing rattly engine when using CP pistons.

my piston to bore clearances are none of your business...i don't want to give you any more free advice. :banana:

Yeah nice.

But when he cranks the boost up and binds the ring ends because you told him to run 17thou, how are you going to explain that to this guy. If you don't follow the instructions made by the manufacturer then you are asking for problems. Or do you just choose the information you adhere to or not? I don't really care what piston to bore clearance you run and I certainly don't need your advice. I just think you need to think about the consequences of giving advice like that in a place like this.

Link to comment
https://www.sau.com.au/forums/topic/239144-cp-ring-gap/#findComment-4180313
Share on other sites

Great! so now you know more than the piston manufacturer. Congratulations.

I just hope this guy has the good sense to not listen to your comment and instead listen to the people who make the piston and rings.

But hey, I could be wrong. While you're at it, give him your rule of thumb on piston to bore clearances. We wouldn't want him making the mistake of using the piston manufacturers specs on that one.

Run them where you/he likes...its your/his engine

ask my customers have they ever had a problem with an excessive breathing rattly engines when using CP pistons.

my piston to bore clearances are none of your business...i don't want to give you any more free advice. :banana:

Edited by DiRTgarage
Link to comment
https://www.sau.com.au/forums/topic/239144-cp-ring-gap/#findComment-4180305
Share on other sites

....and I wouldn't call 28thou excessive in a 3.425 inch bore. People cringed when engine builders started running closer to 3thou BE clearances but it was all for a reason. Ring technology these days is that far advanced from the 90's. You don't need to run tighter end gaps to keep it sealed.

Link to comment
https://www.sau.com.au/forums/topic/239144-cp-ring-gap/#findComment-4180324
Share on other sites

After seeing how well my engine stood up to the work i put it through before the clutch explosion, I am not arguing with 3lit3 32. I dragged it, raced it, and generally did all you can do in a high performance car. On teardown the piston.s rings. and bore.s were still like new. He built it and is building the replacement and i wouldnt have it any other way.

Link to comment
https://www.sau.com.au/forums/topic/239144-cp-ring-gap/#findComment-4180325
Share on other sites

ive already done them to elites spec. and yeah its also what cp reccommend so cant be too wrong. just wanted to double check. last thing i want is the rings binding. and yeah it is turbo (garrett t04z), planning on running high boost. street car but will be seeing the track a fair bit! thanks again.

Link to comment
https://www.sau.com.au/forums/topic/239144-cp-ring-gap/#findComment-4180842
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...