Rb25det Murder Mystery

[phee]

Hey guys and girls.

First post on this forum so play nice

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.

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

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

Phee

Edited May 25, 2006 by phee

[danielson]

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=

[carl h]

perhaps the oil pump slipped?

[R31Nismoid]

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

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.

[Fitzpatrick Speed Works]

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!!

[Fitzpatrick Speed Works]

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!!!???

[blind_elk]

I'll put my money on a smashed ring - this then allows any boost pressure to pressurise the sump and pump oil out the dipstick tube (after the dipstick gets launched).

Been there, done that.

[mjfawke]

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.

[BezerkR32]

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=

[phee]

Hit me with the rough costs:

a) < 2k

b) between 2 - 4k

c) between 4 - 6k

d) between 6 - 8k

e) 8k >

I know it all depends on what parts I get but just an average would be good.

[Fitzpatrick Speed Works]

basic rebuild with stock stuff around $3g, it goes up from there depending on the parts you use. But my initial figure includes labor.

[shanef]

if your going to be rebuilding it, dont waste ur time and money on a stock rebuild. build it properly with forgies and the associated good bits.

[SECURITY]

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.

[R31Nismoid]

2k is not a realistic price

[T0nyGTSt]

2k is not a realistic price

forged pistons are around the $1,200 mark by itself

it's one of those things where you say 'may as well replace this while it's open'...

[R33fourdoor]

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?

Good luck

[R33fourdoor]

Whoops sorry..... meant "short" motor.

[danielson]

get a 26... lol

[shanef]

get a 26... lol

your half way there...get a 26/30

[danielson]

26/30, nice nice...but i personally like lots of revs

ANYWAY back on topic

Edited May 26, 2006 by danielson