Jump to content
SAU Community

Recommended Posts

Hey guys and girls.

First post on this forum so play nice :angry:

I own a '93 Nissan GT25T Skyline that recently went 'boom'. Some of you might know it if you're located in Brisbane. Had the lancer cut bonnet vents and dual cannons, white. Never the less, she was producing 365hp or 278kw at the rears on 14psi when dynoed in QLD.

post-29267-1148519356.jpg post-29267-1148520221.jpg

She lives in the NT now and ran 13.7 down the quarter on an unprepped track, 30C temp and 12psi.

These are a very general outline of the mods on the car:

G-Max Wheels rear: 18x9.5 with 265’s front: 18x8.5

Tein hight and rebound adjustable suspension

Full 3inch custom exhaust with Magic Cat and twin Mufflers

T70 turbo on X-Force highmount manifold

Turbosmart 48mm Pro-Gate wastegate

100mm think Front Mount Inter Cooler

Blitz blow off valve

Sard fuel pressure Regulator

Sard 550cc injectors

Walbro 500 horsepower fuel pump

Motec Enginge Management System (M600)

Exceedy 5 puck clutch

Pod air filter

Oil catch can

Thermo fan

Bonnet vents

Isotta Steering wheel

DBA 4000series sloted disks alround with braided lines

Braided fuel-line, blow-by, breather and radiator overflow hoses

New chrome radiator overflow tank

Gates Racing radiator hoses

Viper 790VX Pager car alarm

post-29267-1148519428.jpg

Now that I have the general outline of what I own, on the table... I am asking for advise as to why it could have possibly died on me.

This is what happened: (Tuesday 23rd May around 10pm)

Just finished dinner in town and was driving a mate home down the Hwy. A commodore ute was tailing my ass and when I slowed down for the lights I might as well have been piggy backing him. Lights went green so I put my foot down (rolling start, didn't dump the clutch). My boost kicks in around 4100rpm so I was changing gears around 5500. I looked back during a gear shift to see the ute move from behind me into the next lane to pass since I had started to slow down, but as his lights went across my exhaust I noticed smoke pouring out. Foot off the throttle completly and coastered along. Asked my mate if he had seen it and he had but we weren't 100% sure if it was smoke or spray from the tyres going over the water. I first thought it could have been a turbo seal going. I let her go for a bit then dropped her back into third when we got in more light and tried again. This time around during gear shift... no smoke and no turbo lag.

Thought nothing more of it. (That's where I f**ked up)

Got onto a back street a block away from my mates place and I start changing gears around 5500rpm again. (My redline is 6900 - 7000, and rev limiter cuts in around 7200). No turbo lag, no smoke from what we could see but being a back street all we had were headlights. There was a car oncoming so I didn't use my high beams which could have helped me see the smoke coming from under the bonnet but that aside. Driving along as normal and we pass the oncoming car. Then we both start to smell somthing (which we originally thought was the cars exhaust we just past) but it hung around. I backed off again for the upcoming intersection. I still didn't realise what had happened yet. We got back into street lights and that's when I realised that the smell was from my car. If I stopped at the T junction I wouldn't have made it across. Back into second and I tried to merge across the lanes but any pressure on the throttle and the engine would shudder. I put my foot on the clutch, put her in netural, and took my foot off and just rolled to a stop. Engine off. That's when I saw the smoke. Was about to get my extinguisher but it was obviously it was only burning oil so I didn't bother. Popped the bonnet and almost died.

This is what we saw:

* Dipstick blown out (excessive pressure in the sump)

* Clean oil on left hand side of engine bay (including roof of bonnet)

* Right hand side of engine looked clean still and the block looked intack.

* Radiator intack, and temp guage didn't rise.

Being me (and I am sure I wouldn't be the only one to try this), I wanted to know if she would start again. Nope. Wanted to crank but it wasn't having much luck in doing so. Left her alone after that. Cleaned up the oil and got her towed to my mates place by another mate who came down to help diagnose the f**k up.

My mate checked the oil level yesterday (Wed 24th May) and the stick said she was still full, and the oil still clean with no traces of water. Today I hope to pull the plugs and see if there is any water or oil on one of them.

Relating issues:

* Oil was changed 2 weeks ago from really gluggy black old motul oil to new motul. She had to be flushed 3 times before I could put the new oil in. Had been between 10,000 - 15,000kms since last service.

* I thought I would be clever and save some cash by putting in Unleaded fuel with a bottle of octain boost that I had left over from when I drove her back to Darwin from QLD in March. I used this method once on the trip back but only cause I had no choice, and nothing went wrong then. I am kicking myself over this, you don't need to say anything... but getting paid monthly sucks ass

There was NO noise, and NO physical feeling when the sump rejected the dipstick. The only sign was that we could smell burning oil. (We both didn't even register it was oil cause it was clean oil and not dirty oil). The engine or turbo didn't seem to 'fail' until I had slowed right down and tried to accelerate again.

I have already been told what a few repairs could be including new bottom end, which is all well and good, but has anyone else had this problem before? Do you know what the cause was?

Any help and advise will be appreciated, as well as what you did or your mate did to repair their engine when something like this happened. I don't think I want to know how much it cost.

Cheers guys and girls :wub:

Phee

Edited by phee
Link to comment
https://www.sau.com.au/forums/topic/119388-rb25det-murder-mystery/
Share on other sites

you have blown a piston(s)... sounds like youv done the ring lands, or just badly burnt rings. could be muliple cyinders, either way, REBUILD TIME.... look here, it happened to me too.......

http://www.skylinesaustralia.com/forums/in...opic=119286&hl=

So it wasnt cranking easily?

Big end bearing... possibly piston rings but then i drove mine around for a month with two screwed pistons, blew a lot of oil :P

Have you dont a compression/leakdown test as yet?

Thats probably the best place to begin.

That will tell the story that i think most are going to suspect is gonna be a case of motor out & rebuild time.

I dont think its nessessarily a blown piston, but it could be as the piston is letting the crank case fill with air but this isnt how it usually works. The smoke could just be oil getting onto the exhaust and burning off??? I dont think its the oil pump easy to check whind it over on a mechanical gauge and see if it build pressure?? Over filled, i doubt that too. I would be pulling the head off and checking the pistons and bore especially once you discounted things like oil surge, overfilled, turbo seals etc... Also this will check the head at the same time in a very unlikely circumstance you could have dropped a valve and this has casue pressue to casue other problems, but as mentioned I would look to having a look inside the motor!!

Big end doesnt explain the oil smoke, nor the fact it was a little intermittent, and it wouldn't casue crank case pressure. Are you sure the dipstick was in properly from the onset of the trip. you could have not put it in properly and the oil blew everywhere then a fueling problem started as mentioned you had poor fuel in the car, and due to the coincidence you have blamed the wrong thing!!!???

I'm going to go with blown piston(s), but the fact she won't crank is a worry - assuming detonation has killed a piston, it has probably pounded out the bearing as well. If you can find someone with a bore scope, they can have have a quick look at the piston tops to see if it is worth pulling the motor down. And if your breather enters the system before the turbo, you are also going to have some fun cleaning out the pipework and the IC.

sounds spot on, major lean out.

you have blown a piston(s)... sounds like youv done the ring lands, or just badly burnt rings. could be muliple cyinders, either way, REBUILD TIME.... look here, it happened to me too.......

http://www.skylinesaustralia.com/forums/in...opic=119286&hl=

i've spent around 2k on my rebuild. thats with an n1 oil pump, new rings, thermostat, crank regrind, vrs kit bla bla bla... it helps to have mates in the industry.

check if your state had a deal going on with the local nissan dealer for parts.. that'll definatley cut costs a bit.

Hi Phee,

I guess it would all depend on how much money you have set aside for this sort of thing and what value you place on it.

Considering you had a stock bottom end to start with, I would have thought that purchasing a good long motor from an importer would be an option!? It would certainly be less expensive overall (re-using your top end and ancillaries) and it would get you back up and running the quickest way possible. My car is my daily driver and my only set of wheels, so this would be my first choice as I couldn't afford to have my car off the road for weeks on end.

Once you're up and running, you could start saving up your money and have your spare bottom end rebuilt at your leisure (with all the "good bits").

Sounds like a plan? :D

Good luck

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

    • Driveability will be about the same with either externally venting BOV, or no BOV at all. Perhaps worse one way than the other, with me thinking that the definitely more flow going through the AFM through a venting BOV more likely to cause rich stalls than the perhaps more flow that the AFM might read on reversion. There is no such thing as "turbo damage" from not having a BOV at stock, or even quite a lot higher than stock, power levels. You need a big turbo with a lot of mass spinning hard getting a horrible slowdown from a slammed shut throttle before there is anything like the shaft loads required to damage things. Not an issue on small turbos. The ONLY 2 reasons that Nissan put a recirc valve onto the RB were: It is a bypass valve. It is open when under vacuum. When not on boost, it bypasses intake air forward around the compressor, which unloads the compressor, allowing the turbine to sping more freely, making the whole lot a bit more efficient when just puddling around. Throttle response should also be faster via the shorter, smaller diameter BOV pipe (when in NA, ie before the BOV closes and boost is building) which is nicer for driveability. Emissions. The reversion causes CO pulses. Eliminate the reversion (or at least, keep it away from the AFM) and you don't get that. The stalling/driveability aspect could have been tuned around, as shown one example of by dose above, if Nissan hadn't put a recirc valve on. Many many turbo engines before the RB had no BOV. They did not stall. See the RB30 turbo as an example. Nistune is definitely better than just stock ECU. It allows you to access and change things that are not excellent on the stock setup, and allows you to do mods like put decent injectors in, relocate the AFM, put a bigger turbo or even cams, etc, on, change to coil swith completely different swell needs, etc etc. All the things that you might need or want to do 25 years after the car was new. Aftermarket replacement ECU is obviously better again, because it gives you even more freedom from the constraints of the stock ECU. I won't be needing to go any further than Nistune though, for the new turbo in the 250ish rwkW region I'm going to, with big injectors, and most other things being stockish.
    • Lucky the prp block is supposed to be released next weekend 
    • Wow guys thank you very much for the HUGE info :-) @GTSBoy I have like 30 minutes if test drive with that car/engine and it not stalled once. IMO it ran very smooth so i guess it was not that bad(but asi i said it is stock) That atmo BoV is worse than no BoV or in my case or it is/will be the same? Cuz frankly i rather have little whooosh sound than that sututu 😄 But either way the less harmfull for engine/turbo the better(if the stock is not an option right away) Yeah about that rebuild i talk with guy who will be doing swap and custom pipes...i think i can get stock BoV or get aftermarket which will function the same. Yeah i looked at that R35 option and i try ask my mechanic more about that if he knows. The engine has stock ECU but i can get Nistune for it. On that stock it runs quite well...but i have limited time with it so rly dont know. Ecumaster is this https://www.ecumaster.com/  It is not some dodgy backyard ECU :-)  @MBS206 Yeah but it will be better to have Nistune than the completely stock ECU no? About that "same" atmo/no BoV. The drivebility would be the same? I dont know but i kinda guess that amto BoV would cause more problems than no BoV in my case? Or is the same? You just "change" one sound for the other? Yeah i read many many many topic about hurting the turbo. But no one know anybody that would 100% tell that his turbo/engine blows/get damaged by not running BoV. Of course turbo would be little happier IMO if it has BoV ..but if you do not trash i think i should be good. And as you can see iam already trying to get this right...just working what i have right now :-) Yeah iam kinda the same...i dont want nothing loud and frankly iam not liking that sututu noise that much 😄 i rather have little bit of "whooosh" or no sound at all. Of course in my case it si a completely another world when you came tu Turbo car with open air box and no BoV and you driving the N/A ...all i hear is engine. Here? I heard turbo/sucking and that sututu 😄 @Yeetus So in my case it is really no difference to run no BoV or some atmo BoV like GReddy FV2? The car would drive the same and has "the same" little problems? As i wrote above i kinda thinked that atmo BoV with stock MAF would cause more problems...but then again i dont know much about no BoV either :-)  So to avoid stalling i "cant" just put neutral on stop lights like from higher rpm? Or? Yeah iam already looking for ECU :-)  Yes iam at the same side with thar R35 MAF :-)  @Dose Pipe Sutututu Thank you i (my mechanic/tuner) will look into that) Guess iam taking the Nistune at least :-) 
    • Here's the workaround with Nistune I was talking about, just add in more timing on the decel table And play around with the fuel cut & recovery, it's enough to stop it from stalling on a decel  
    • Hi Apex and welcome! 
×
×
  • Create New...