Jump to content
SAU Community

Recommended Posts

well i have (had) a rb25det s2..

gt3076r .82 @16psi

38mm gate

stock 25

splitfires

740cc

gtr pump

nistune

fmic etc etc..

now i had a grip day at mallala and the car was strong and did 15-20 laps, slight traction loss to limiter..

then i was exiting a corner (on the 15th-20th lap) and oil shot out my rocker covers..

then contnued for the rest of the day, when i exceeded 5-6000rpm..

i thought this was the usual rb issue so thought nothing of it..

bought baffles and rb26 rocker covers..

now i got the car to my workshop, to install plazmaman plenum, rocker covers and baffles..

got it on the dyno and excessive blowby, oil into catch can.. RINGS GONE!

any reason y the rings went all of a sudden?

tune related?

now im up for a rebuild!?

cheers

Link to comment
https://www.sau.com.au/forums/topic/325005-why-my-rings-failed/
Share on other sites

  • Replies 72
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

First thing to do would be comp and leakdown as stated above and agree with the post above that 15 - 20 laps flat out would have your standard bottom end working pretty hard as cylinder temps would be right up there. What sort of A/F are you running and Does the nistune have air temp compensation ?. I would hazzard a guess that more than likely due to cylinder temp and probably some detonation that you will have a piston that has started to go soft allowing the crown to start to collapse pinching a ring allowing excessive blow bye But untill you do a comp and leakdown test you really wont know.

100% tune related.

the ring lands die from excessive heat and detonation. a 3076r @ 280rwkw on a 25 warrants neither.

its not to say it couldnt be user error, yet generally my cars see 30 minute floggings at a time and are yet to see this issue.

what are your AFs like? in the 12s i bet

you would think that 280kw wouldnt want to kill them...

does the tune have a big factor in this?

100% tune related.

the ring lands die from excessive heat and detonation. a 3076r @ 280rwkw on a 25 warrants neither.

its not to say it couldnt be user error, yet generally my cars see 30 minute floggings at a time and are yet to see this issue.

what are your AFs like? in the 12s i bet

See i'd argue that it was 100% tune related. You don't know that for certain.

5-7 laps will get a large amount of heat into everything that's for sure, especially upper RPM's.

You don't know the perevious history of the motor either. It might have had a rough life before the current owner as an example.

Could even have been running slightly lean for a number of reasons.

All of which are totally unrelated to the tune.

Either way I'm far from surprised. Tracking a motor @ around 2.5x the factory output - something will give eventually. :blink:

A few stock, good condition/low KM RB26's have been tracked for 2-3 years @ 300-330rwkw, they eventually have died also. Just how it goes.

There are also plenty of cars getting around with AFR's in the 12's on the circuit without a drama after years (these are built mind you).

Honestly what caused the motor to fail IMO could have been any long number of things, and perhaps not a singular one thing but a culmination of several.

You don't know the perevious history of the motor either. It might have had a rough life before the current owner as an example.

Very true, that could be the missing link.

I guess we dont really know enough of its history to give an accurate opinion, with this owner or the last.

yeh al good guys.. the engine will be getting removed today..

i have a new bottom end arriving soon, just dont want this happening to the built one!

ill take some snaps of the bottom end wen it comes out.

also would i need to do any work to the head to bolt it to my new block?

It may have been tune related, BUT, parts can fail, as ash said you are pushing 2.5x the factory power output, parts in F1 engines fail and they have the absolute best of everything inside them, so I wouldnt just be blaming the tune.

yeh totally understand..

i wasnt expecting it to hang in there forever..

just wanted some enlightment...

ill strip it down and take a look and hopefully learn..

but ill start a build thread soon :P

yeh al good guys.. the engine will be getting removed today..

i have a new bottom end arriving soon, just dont want this happening to the built one!

For insurance, you could install a wideband AFR, and an oil pressure gauge. That way you can keep an eye things - eg if a FPR or fuel pump are flaky you will see the full load AFRs change and can take action before the motor pops.

Also - what oil were you using?

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

    • I did end up getting it sorted, as GTSBoy said, there was a corroded connection and wire that needed to be replaced. I ended up taking out the light assembly, giving everything a good clean and re-soldered the old joints, and it came out good.
    • Wow, thanks for your help guys 🙏. I really appreciate it. Thanks @Rezz, if i fail finding any new or used, full or partial set of original Stage carpets i will come back to you for sure 😉 Explenation is right there, i just missed it 🤦‍♂️. Thanks for pointing out. @soviet_merlin in the meantime, I received a reply from nengun, and i quote: "Thanks for your message and interest in Nengun. KG4900 is for the full set of floor mats, while KG4911 is only the Driver's Floor Mat. FR, RH means Front Right Hand Side. All the Full Set options are now discontinued. However, the Driver's Floor Mat options are still available according to the latest information available to us. We do not know what the differences would be, but if you only want the one mat, we can certainly see what we can find out for you". Interesting. It seems they still have some "new old stock" that Duncan mentioned 🤔. I wonder if they can provide any photos......And i also just realized that amayama have G4900 sets. I'm tempted too. 
    • Any update on this one? did you manage to get it fixed?    i'm having the same issue with my r34 and i believe its to do with the smart entry (keyless) control module but cant be sure without forking out to get a replacement  
    • So this being my first contribution to the SAU forums, I'd like to present and show how I had to solve probably one of the most annoying fixes on any car I've owned: replacing a speedometer (or "speedo") sensor on my newly acquired Series 1 Stagea 260RS Autech Version. I'm simply documenting how I went about to fix this issue, and as I understand it is relatively rare to happen to this generation of cars, it is a gigantic PITA so I hope this helps serve as reference to anyone else who may encounter this issue. NOTE: Although I say this is meant for the 260RS, because the gearbox/drivetrain is shared with the R33 GTR with the 5-speed manual, the application should be exactly the same. Background So after driving my new-to-me Stagea for about 1500km, one night while driving home the speedometer and odometer suddenly stopped working. No clunking noise, no indication something was broken, the speedometer would just stop reading anything and the odometer stopped going up. This is a huge worry for me, because my car is relatively low mileage (only 45k km when purchased) so although I plan to own the car for a long time, a mismatched odometer reading would be hugely detrimental to resale should the day come to sell the car. Thankfully this only occurred a mile or two from home so it wasn't extremely significant. Also, the OCD part of me would be extremely irked if the numbers that showed on my dash doesn't match the actual ageing of the car. Diagnosing I had been in communication with the well renown GTR shop in the USA, U.P.garage up near University Point in Washington state. After some back and forth they said it could be one of two things: 1) The speedometer sensor that goes into the transfer case is broken 2) The actual cluster has a component that went kaput. They said this is common in older Nissan gauge clusters and that would indicate a rebuild is necessary. As I tried to figure out if it was problem #1, I resolved problem #2 by sending my cluster over to Relentless Motorsports in Dallas, TX, whom is local to me and does cluster and ECU rebuilds. He is a one man operation who meticulously replaces every chip, resistor, capacitor, and electronic component on the PCB's on a wide variety of classic and modern cars. His specialty is Lexus and Toyota, but he came highly recommended by Erik of U.P.garage since he does the rebuilds for them on GTR clusters.  For those that don't know, on R32 and R33 GTR gearboxes, the speedometer sensor is mounted in the transfer case and is purely an analog mini "generator" (opposite of an alternator essentially). Based on the speed the sensor spins it generates an AC sine wave voltage up to 5V, and sends that via two wires up to the cluster which then interprets it via the speedometer dial. The signal does NOT go to the ECU first, the wiring goes to the cluster first then the ECU after (or so I'm told).  Problems/Roadblocks I first removed the part from the car on the underside of the transfer case (drain your transfer case fluid/ATF first, guess who found out that the hard way?), and noted the transfer case fluid was EXTREMELY black, most likely never changed on my car. When attempting to turn the gears it felt extremely gritty, as if something was binding the shaft from rotating properly. I got absolutely no voltage reading out of the sensor no matter how fast I turned the shaft. After having to reflow the solder on my AFM sensors based on another SAU guide here, I attempted to disassemble the silicone seal on the back of the sensor to see what happened inside the sensor; turns out, it basically disintegrated itself. Wonderful. Not only had the electrical components destroyed themselves, the magnetic portion on what I thought was on the shaft also chipped and was broken. Solution So solution: find a spare part right? Wrong. Nissan has long discontinued the proper sensor part number 32702-21U19, and it is no longer obtainable either through Nissan NSA or Nissan Japan. I was SOL without proper speed or mileage readings unless I figured out a way to replace this sensor. After tons of Googling and searching on SAU, I found that there IS however a sensor that looks almost exactly like the R33/260RS one: a sensor meant for the R33/R34 GTT and GTS-T with the 5 speed manual. The part number was 25010-21U00, and the body, plug, and shaft all looked exactly the same. The gear was different at the end, but knowing the sensor's gear is held on with a circlip, I figured I could just order the part and swap the gears. Cue me ordering a new part from JustJap down in Kirrawee, NSW, then waiting almost 3 weeks for shipping and customs clearing. The part finally arrives and what did I find? The freaking shaft lengths don't match. $&%* I discussed with Erik how to proceed, and figuring that I basically destroyed the sensor trying to get the shaft out of the damaged sensor from my car. we deemed it too dangerous to try and attempt to swap shafts to the correct length. I had to find a local CNC machinist to help me cut and notch down the shaft. After tons of frantic calling on a Friday afternoon, I managed to get hold of someone and he said he'd be able to do it over half a week. I sent him photos and had him take measurements to match not only the correct length and notch fitment, but also a groove to machine out to hold the retentive circlip. And the end result? *chef's kiss* Perfect. Since I didn't have pliers with me when I picked up the items, I tested the old gear and circlip on. Perfect fit. After that it was simply swapping out the plug bracket to the new sensor, mount it on the transfer case, refill with ATF/Nissan Matic Fluid D, then test out function. Thankfully with the rebuilt cluster and the new sensor, both the speedometer and odometer and now working properly!   And there you have it. About 5-6 weeks of headaches wrapped up in a 15 minute photo essay. As I was told it is rare for sensors of this generation to die so dramatically, but you never know what could go wrong with a 25+ year old car. I HOPE that no one else has to go through this problem like I did, so with my take on a solution I hope it helps others who may encounter this issue in the future. For the TL;DR: 1) Sensor breaks. 2) Find a replacement GTT/GTS-T sensor. 3) Find a CNC machinist to have you cut it down to proper specs. 4) Reinstall then pray to the JDM gods.   Hope this guide/story helps anyone else encountering this problem!
    • So this being my first contribution to the SAU forums, I'd like to present and show how I had to solve probably one of the most annoying fixes on any car I've owned: replacing a speedometer (or "speedo") sensor on my newly acquired Series 1 Stagea 260RS Autech Version. I'm simply documenting how I went about to fix this issue, and as I understand it is relatively rare to happen to this generation of cars, it is a gigantic PITA so I hope this helps serve as reference to anyone else who may encounter this issue. NOTE: Although I say this is meant for the 260RS, because the gearbox/drivetrain is shared with the R33 GTR with the 5-speed manual, the application should be exactly the same. Background So after driving my new-to-me Stagea for about 1500km, one night while driving home the speedometer and odometer suddenly stopped working. No clunking noise, no indication something was broken, the speedometer would just stop reading anything and the odometer stopped going up. This is a huge worry for me, because my car is relatively low mileage (only 45k km when purchased) so although I plan to own the car for a long time, a mismatched odometer reading would be hugely detrimental to resale should the day come to sell the car. Thankfully this only occurred a mile or two from home so it wasn't extremely significant. Also, the OCD part of me would be extremely irked if the numbers that showed on my dash doesn't match the actual ageing of the car. Diagnosing I had been in communication with the well renown GTR shop in the USA, U.P.garage up near University Point in Washington state. After some back and forth they said it could be one of two things: 1) The speedometer sensor that goes into the transfer case is broken 2) The actual cluster has a component that went kaput. They said this is common in older Nissan gauge clusters and that would indicate a rebuild is necessary. As I tried to figure out if it was problem #1, I resolved problem #2 by sending my cluster over to Relentless Motorsports in Dallas, TX, whom is local to me and does cluster and ECU rebuilds. He is a one man operation who meticulously replaces every chip, resistor, capacitor, and electronic component on the PCB's on a wide variety of classic and modern cars. His specialty is Lexus and Toyota, but he came highly recommended by Erik of U.P.garage since he does the rebuilds for them on GTR clusters.  For those that don't know, on R32 and R33 GTR gearboxes, the speedometer sensor is mounted in the transfer case and is purely an analog mini "generator" (opposite of an alternator essentially). Based on the speed the sensor spins it generates an AC sine wave voltage up to 5V, and sends that via two wires up to the cluster which then interprets it via the speedometer dial. The signal does NOT go to the ECU first, the wiring goes to the cluster first then the ECU after (or so I'm told).  Problems/Roadblocks I first removed the part from the car on the underside of the transfer case (drain your transfer case fluid/ATF first, guess who found out that the hard way?), and noted the transfer case fluid was EXTREMELY black, most likely never changed on my car. When attempting to turn the gears it felt extremely gritty, as if shttps://imgur.com/6TQCG3xomething was binding the shaft from rotating properly. After having to reflow the solder on my AFM sensors based on another SAU guide here, I attempted to disassemble the silicone seal on the back of the sensor to see what happened inside the sensor; turns out, it basically disintegrated itself. Wonderful. Not only had the electrical components destroyed themselves, the magnetic portion on what I thought was on the shaft also chipped and was broken. Solution So solution: find a spare part right? Wrong. Nissan has long discontinued the proper sensor part number 32702-21U19, and it is no longer obtainable either through Nissan NSA or Nissan Japan. I was SOL without proper speed or mileage readings unless I figured out a way to replace this sensor. After tons of Googling and searching on SAU, I found that there IS however a sensor that looks almost exactly like the R33/260RS one: a sensor meant for the R33/R34 GTT and GTS-T with the 5 speed manual. The part number was 25010-21U00, and the body, plug, and shaft all looked exactly the same. The gear was different at the end, but knowing the sensor's gear is held on with a circlip, I figured I could just order the part and swap the gears. Cue me ordering a new part from JustJap down in Kirrawee, NSW, then waiting almost 3 weeks for shipping and customs clearing. The part finally arrives and what did I find? The freaking shaft lengths don't match. $&%* I discussed with Erik how to proceed, and figuring that I basically destroyed the sensor trying to get the shaft out of the damaged sensor from my car. we deemed it too dangerous to try and attempt to swap shafts to the correct length. I had to find a local CNC machinist to help me cut and notch down the shaft. After tons of frantic calling on a Friday afternoon, I managed to get hold of someone and he said he'd be able to do it over half a week. I sent him photos and had him take measurements to match not only the correct length and notch fitment, but also a groove to machine out to hold the retentive circlip. And the end result? *chef's kiss* Perfect. Since I didn't have pliers with me when I picked up the items, I tested the old gear and circlip on. Perfect fit. After that it was simply swapping out the plug bracket to the new sensor, mount it on the transfer case, refill with ATF/Nissan Matic Fluid D, then test out function. Thankfully with the rebuilt cluster and the new sensor, both the speedometer and odometer and now working properly!   And there you have it. About 5-6 weeks of headaches wrapped up in a 15 minute photo essay. As I was told it is rare for sensors of this generation to die so dramatically, but you never know what could go wrong with a 25+ year old car. I HOPE that no one else has to go through this problem like I did, so with my take on a solution I hope it helps others who may encounter this issue in the future. For the TL;DR: 1) Sensor breaks. 2) Find a replacement GTT/GTS-T sensor. 3) Find a CNC machinist to have you cut it down to proper specs. 4) Reinstall then pray to the JDM gods.   Hope this guide/story helps anyone else encountering this problem!
×
×
  • Create New...