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Fresh RB25 dead after 1 lap?

OSH1FT

By OSH1FT,
in Engines & Forced Induction

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OSH1FT Enthusiast

OSH1FT

Posted
Posted

Hi all,

Earlier this year my 25 neo in my 34 did a head gasket during a track day. Had that fixed up and shortly after ran into more trouble which was diagnosed as rings. $6k and 10 months later with a freshly rebuilt motor I hit my 2nd track day of the year and the car has turned around and chewed through another head gasket on the first lap.

Motor was tuned, ran fine on the dyno in heat, didn't make as much power as pre rebuild but we attributed that to the hot weather.

Found shit loads of oil in the coilpack valley, after opening the bonnet up, but only in cyl 1-2, assuming this was spat out of the breather. Motor now has shitloads of blow by, is running on 5 and obviously is spitting white smoke out of the exhaust like crazy.

Trying to figure out how exactly it's managed to eat a head gasket (and do the rest of the damage it's done to my motor) after one hot lap of Winton. Coolant was boiling when I pulled off the track, powersteering was also overflowing (which set my manifold on fire, yay)

before anyone says check your temps, stock gauge said I was slightly above half, which is what I expected given it was a 35 degree day.

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https://www.sau.com.au/forums/topic/472788-fresh-rb25-dead-after-1-lap/
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GTofuS-T Grand Master

GTofuS-T

Posted
Posted
24 minutes ago, OSH1FT said:

before anyone says check your temps, stock gauge said I was slightly above half, which is what I expected given it was a 35 degree day.

This is just going to make people tell you the stock gauge isn't accurate enough track use

Leroy Peterson Grand Master

Leroy Peterson

Posted
Posted

I've had a similar experience, except I cooked the bottom end bearings on the 2nd track day. And it had done run in kms plus a light track day on run in tune.
My oil pressure and temp gauges didn't pick up any issues, but they weren't monitoring in the spots with the problem....

Anyway, I learnt that building a motor doesn't always fix the problem that caused the motor to die in the first place.
In my case it was the external oil filter/cooler setup, which remained unchanged between motor builds.

What type headgasket? Thickness? What boost? Aftermarket headstuds?
Aftermarket radiator?

djr81 Grand Master

djr81

Posted
Posted (edited)

Its probably all conjecture and meaningless until you have worked out what your damage is.

So turbo is gone?

Loss of compression blown gasket or busted rings?  So are there results from a compression test and/or sniffer in the radiator if the thing still runs.

Is the bottom end ok?

Power steer can overheat and overflow but not after one lap usually.

Comes down to what is different between a dyno and the track. Oil surge is possible but unlikely to be fatal after one lap. Bad fuel and or fuel surge will cause problems more quickly.  Damage caused quickly is overwhelmingly combustion related rather than oil/coolant related.  The only other thing that fleetingly comes to mind is an over rev/over boost.

Its a depressing thought but more than one thing may have been busted.

 

Edited by djr81
OSH1FT Enthusiast

OSH1FT

Posted
  • Author
Posted
10 hours ago, djr81 said:

Its probably all conjecture and meaningless until you have worked out what your damage is.

So turbo is gone?

Loss of compression blown gasket or busted rings?  So are there results from a compression test and/or sniffer in the radiator if the thing still runs.

Is the bottom end ok?

Power steer can overheat and overflow but not after one lap usually.

Comes down to what is different between a dyno and the track. Oil surge is possible but unlikely to be fatal after one lap. Bad fuel and or fuel surge will cause problems more quickly.  Damage caused quickly is overwhelmingly combustion related rather than oil/coolant related.  The only other thing that fleetingly comes to mind is an over rev/over boost.

Its a depressing thought but more than one thing may have been busted.

 

So we drained the oil out from the coilpack valley and the car actual runs smoothly and sounds good. doesn't misfire, sounds very much like compression is okay. Will be testing tonight or tomorrow when I can borrow a kit.

Only blowing white smoke under load so I'm assuming turbo is on its way out. Again, gotta pull that off in the next couple of days to figure it out.

Really just cant figure out the connection to the excessive blow by and the turbo going at the same time.

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