Jump to content
SAU Community

Recommended Posts

drifted my brothers 180sx today, 185rwkw 15 then bleeding off to 12psi. 20 mins intervouls and filled up a whole drift catch can (i think 1L) which is a f**kload too much, so kept pouring back into the engine as it was still good.

Looks like the engine will be stripped, new block, re ringed pistons and re assembled propperly

no no. its a clearance issue. my sujestion is to have a look at the bores. when you did the rings did you chamfer the edges whewre you filed them?

if its ok. stick in some woolworths oil and give it a hard time for a few hundred kays.

From what I have read of this thread, in my opinion it's simply a matter of too much oil getting to the cylinder head. It's not blowing it by, it's simply filling up the cam covers at high rpm. ONE OIL FEED IS ENOUGH, that's why RB26's have one blocked off STANDARD.

So get on with it, pull the head off and block off one of the oil feeds. Check the bore while you are at it to satisfy the "blow by" callers.

Why is it doing it on this rebuild? Because you are using higher rpm and/or more frequently and/or for longer periods. If you aren't, then you wasted your money on forged pistons. It only takes a little bit to tip it over return to sump flow rate.

:D cheers :D

sky30, we left it at one stage and overfilled and spat it all over the joint.

I didnt build the motor, MSC Performance built it and duggans rooted the machining, thats all it is, a shit build with a shit machine and an overpriced job.

i had the same kind of problem. i used to lose around 2L of oil every few days, but im running nowhere near that kind of power.

the problem was the oil drain pipe being blocked by the pcv - the build up of pressure in the crank wasnt letting the oil return flow freely.

same principle COULD apply here.

i noticed that you said the oil return for the head was routed to the oil return for the turbo. is it possible that the return you plumbed into the turbo drain pipe blocking the oil drain for the turbo? its possible that the oil is backing up all the way to the turbo then being forced out of the oil seal ring.

i had the same kind of problem. i used to lose around 2L of oil every few days, but im running nowhere near that kind of power.

the problem was the oil drain pipe being blocked by the pcv - the build up of pressure in the crank wasnt letting the oil return flow freely.

same principle COULD apply here.

i noticed that you said the oil return for the head was routed to the oil return for the turbo. is it possible that the return you plumbed into the turbo drain pipe blocking the oil drain for the turbo? its possible that the oil is backing up all the way to the turbo then being forced out of the oil seal ring.

Its spitting litters of oil into a catch can not burning or leaking it. The problem is not apparent on the dyno but perhaps not enough sustained high rpm loading is seen during a dyno ramp to fill the head. Which brings us back to the restrictor sizing as had been mention by sydney kid.

Its spitting litters of oil into a catch can not burning or leaking it. The problem is not apparent on the dyno but perhaps not enough sustained high rpm loading is seen during a dyno ramp to fill the head. Which brings us back to the restrictor sizing as had been mention by sydney kid.

i didnt see where he said it was emptying into a catch can. my bad.

yeah but.... what has changed compared to the old motor in regard to revs/boost etc etc. from the sound of it its the same motor just with forgies and thats it.

he was running 15psi, now hes running 18. i know its a long shot, but could that have anything to do with it?

the head return may be blocked because of the combined oil drain. i've proven to be useless in this matter so now im just throwing up ideas.

regardless of that. it wasnt doing it before. 3 pound is f**k all more boost. and its not the oil return. the factory isnt idiots.

i agree theres oil up top. but whats making it "blow out"? corner g-forces i think not.

also. what turbo is on it????? this may sound strange but with my gtr i thought i stuffed the engine when it took aprox 5-10 mins of full boost driving to cover my engine bay and guards in oil after filling up the catchtank.(they were out of a blown motor with spun bearings)

the problem? worn out turbo thrust bearings. it seems boost was leaking past the bearings in the turbo,presurising the crankcase and blowing it out the breathers.

new turbo=fixed.

worth a look at. if you have a smoke tester or make up a adapter to presurise the inlet tract befor the throttle body to see if t is thr turbo leaking.

if not. do a leakdown test.

also a long shot. has any part of the sump changed?? of the windage trays not been installed??

SK- Okay head is off- bores look very good. Blocking one oil feed off. I believe the CPs will have more blow by than std and that may be enough to tip it over the edge. The old build would spit a little bit out but only when it fluttered the rings on limiter for extended periods of time. Thanks for your input.

Running in was about 20 seconds of getting oil pressure followed by nothing but full throttle (only 6psi or so) and no big decels for the first 150km. Then it had 600km of hard driving with no extended cruise or idling times. I used the cheapest oil i could find. Then it went back to the dyno for the 18psi tune.

T04GTR- Ring gaps were as per CP setup info- about .026"-.028" Can't remember which ring was larger gap. Yes I chamfered all the rings. The only vertical lines in the bore are from the piston skirt and they are very minimal.

Edited by lukevl

this is such an annoying problem!! it used to piss me off badly.. mine did it because every piston had cracked rings and the boost was going into the crank case..

Once it blew by that much that a whole litre of oil squirted onto the red hot exaust manifold... No fire.. just a SHITLOAD of smoke. never have you seen a cloud of smoke that big :P

I even pulled my head off and blocked off one hole and it made a big difference but still squirted because of the rooted engine.

Ever since i got my engine rebuilt with ACL forgies i have not had any issues at all... not have i even checked it.. i have my catch can plumbed back into the intake because i like to keep it legal.

Might check it for blow by on my next dyno session...

i think the fact it fills the can on high boost, but not on low boost tells me it's rings/bores. and you said even when thrashing on low boost it doesn't fill the can (so it's not the high revs pumping all that oil that's doing it), but when you are running on high boost you are filling the can. so to me the diagnosis seems clear. but there is only one way to find out for sure. :blink:

Beer Baron- not really. Going from low to high boost gives it about 12psi and over 120rwkw or so. That is going to make a lot more positive crank case pressure. The motor will always make positive crankcase pressure due to the cylinder pressure getting past the rings. Its probably just very close to spitting oil out on low boost.

EDIT- Its fixed. No more oil dramas. Goes like a cut snake and doesn't regurgitate oil. I love it. 'SK- I am sure you are very shocked by this. Thanks

Edited by lukevl

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

    • Please use a modern ECU. PowerFC with the Nintendo Gameboy controller is horrible. It's not 2005 anymore.
    • The car/ECU will have all the sensor that it needs and expect to have. I think i do not have to explain to you how the Link is way better specialy if you have swapped engine   I just do not want to deal with any "problems" cuz i have only Nistune which i learned is not that great and in my case cant even deal with that speed problem (Link can) And of course it will be way more easier to tune and diagnose and safe. And for the ECU/speed problem...i dont know.
    • Per Mark Roberts of Sonictune: Mark Robert Author At this time, no. No ETA either 2016-17 models. You will be able to purchase and install a 2018.5+ TCU though   TCU purchasing and pricing info! As we near the release of TCU tuning, I am going to answer some questions I get asked often.   What do I need for TCU tuning? At this time, you will need a 2018.5+ TCU to be able to tune. If you have a 2016-to early 2018, you will need to replace your TCU with the newer version. One good way to know if your TCU is good is if you have auto upshift in manual mode in 1st gear around 6500 rpms. If your manual 1st gear goes to 7k rpm and will hit the rev limiter unless you shift, you have the older TCU.   Why do I need to buy another ecu license/phone flash if I already have it on my ECU tune? The TCU is its own computer module. It is completely separate from the ECU. Because of this, you will be required to purchase a TCU license and, if your tuner has it, the phone flash license required to tune it via phone/bluetooth.   Do I need TCU tuning? TCU tuning is NOT required. However, the faster your setup, the more it will assist in track and dragy time consistency.   If I’m ECU tuned by (tuner A) can I get my TCU tuned by (Tuner ? Yes, since it’s a different module and a completely separate flash, you can have two different tuners. However, it is highly recommend that you have both tuned by the same tuner. For me, my TCU tuning will directly complement my ECU tuning style and features and running my ECU and another TCU or vice versa MIGHT cause some issues. At this time and for the foreseeable future, I will only be tuning my current ECU tuned customers TCUs.     I have a SYVECS AWD controller. Do I still need it? Yes! The AWD controllers main job is to control your AWD system. However, with TCU tuning, you will no longer need the auto-shift function as that will be done through the TCU. The AWD controller will still be very beneficial for racers looking to maximize traction on the launch.     Shift schedule changes: holding gears longer at lower pedal input as well as max shift rpm changes. Please note, the new ECU race rom coming out will address 90% of the shitty drivability issues these cars have through custom maps from myself and Racebox—as well as others I am sure.   Increase shift speeds: as seen in the videos I’ve been posting, the TCU shifts much faster once tuned.   Increased shift pressures: as also seen in the videos, much firmer full throttle shifts.      
    • Per Mark Roberts of Sonictune:     Mark Robert Author At this time, no. No ETA either 2016-17 models. You will be able to purchase and install a 2018.5+ TCU though   TCU purchasing and pricing info! As we near the release of TCU tuning, I am going to answer some questions I get asked often.   What do I need for TCU tuning? At this time, you will need a 2018.5+ TCU to be able to tune. If you have a 2016-to early 2018, you will need to replace your TCU with the newer version. One good way to know if your TCU is good is if you have auto upshift in manual mode in 1st gear around 6500 rpms. If your manual 1st gear goes to 7k rpm and will hit the rev limiter unless you shift, you have the older TCU.   Why do I need to buy another ecu license/phone flash if I already have it on my ECU tune? The TCU is its own computer module. It is completely separate from the ECU. Because of this, you will be required to purchase a TCU license and, if your tuner has it, the phone flash license required to tune it via phone/bluetooth.   Do I need TCU tuning? TCU tuning is NOT required. However, the faster your setup, the more it will assist in track and dragy time consistency.   If I’m ECU tuned by (tuner A) can I get my TCU tuned by (Tuner ? Yes, since it’s a different module and a completely separate flash, you can have two different tuners. However, it is highly recommend that you have both tuned by the same tuner. For me, my TCU tuning will directly complement my ECU tuning style and features and running my ECU and another TCU or vice versa MIGHT cause some issues. At this time and for the foreseeable future, I will only be tuning my current ECU tuned customers TCUs.     I have a SYVECS AWD controller. Do I still need it? Yes! The AWD controllers main job is to control your AWD system. However, with TCU tuning, you will no longer need the auto-shift function as that will be done through the TCU. The AWD controller will still be very beneficial for racers looking to maximize traction on the launch.     Shift schedule changes: holding gears longer at lower pedal input as well as max shift rpm changes. Please note, the new ECU race rom coming out will address 90% of the shitty drivability issues these cars have through custom maps from myself and Racebox—as well as others I am sure.   Increase shift speeds: as seen in the videos I’ve been posting, the TCU shifts much faster once tuned.   Increased shift pressures: as also seen in the videos, much firmer full throttle shifts.      
    • The fancy pants red shock tower brace is finally incoming from MX5 Mania, getting it shipped from 'Merica has been a long and problematic process, and GWR, the 'Merican supplier will not ship directly to consumers outside of the US, Mania basically had to order a heap of them, the colour choice was silver, or red, and we all know anything red adds 5 killerwasps of dynotorques..... Whilst it does fit over a 2.5, and I've seen a few photos and videos of it being installed and fitting, google also says it might get real close to the FAB9 intake front runner, people in the US says it does fit with the FAB9 intake, except for one person who said it slightly touched.......so there is that.....LOL..... As it seems that I am the first in AU to have this combination of parts there's no local knowledge about fitment, so I'm just a willing guinea pig in this endeavour, I'll cross my fingers and toes and hope for the best In other news, I ordered stuff from China  on the same day I ordered the 23° silicone bend from Victoria, the stuff from China arrived a day ago, the 23° silicone bend is still travelling around Australia thanks to Australia Post, and "may" be here next week
×
×
  • Create New...