pop goes the weasle

[GTR-240Z]

My engine decided to go pop last weekend this nice bit of timing meant I've missed billing, japfest, and drag challenge . So now only 1000 miles and 2 months since getting my car road legal I'm now stripping the engine ready for a rebuild...

Head off nothing looks odd

a little closer

a little closer on cylinder 6. bores not looking to good.

thats not scored that's melted piston stuck to my block

from the top you can see the melted piston edge and the the broken piston ring.

Oh well forged pistons it is .

 

[Bantambunny]

Jesus mate, that's bad news Not that it really matters now but i hope you got your ticket in time. I'd lost all of them and only found them wednesday night so spent 4 quid on delivery to make sure it reached you on friday lol

I didn't make it either, one of my new wheels sprung a major leak and my alarm shorted out immobilising the car so spent the whole day in the rain rewiring the car ready for tomorrow.

Hope you get it sorted soon buddy

Nick

 

[Wyn]

Bad new m8
That must hurt after all that work
Make sure you get the fueling/ timing sorted before you go to far with your next engine.

 

[GTR-240Z]

Jesus mate, that's bad news Not that it really matters now but i hope you got your ticket in time. I'd lost all of them and only found them wednesday night so spent 4 quid on delivery to make sure it reached you on friday lol

I didn't make it either, one of my new wheels sprung a major leak and my alarm shorted out immobilising the car so spent the whole day in the rain rewiring the car ready for tomorrow.

Hope you get it sorted soon buddy

Nick

Yeah arrived Friday but was out so did not collect till today, I have some other tickets from skiddell as well but managed to give them to steve so somebody else could use the track time.

 

[GTR-240Z]

Bad new m8
That must hurt after all that work
Make sure you get the fueling/ timing sorted before you go to far with your next engine.

Going overkill on the block and cooling and will probably do the same on ecu/injectors as I dont want to be doing this again.

All this years bonus is going on it . I'm missing the noise and boost of my car really bad and I'm back to driving the misses snail paced Colt.

 

[Zed2k]

Sorry to hear that, looks like it got real hot in there!!! good luck with the rebuild

 

[twoforty]

Unlucky what a PIA. Get a Wideband O2 hooked up on the next one....worth its weight in gold for street tuning

 

[grolls]

Gutted for you,,get it sorted and kick some ass soon,,,,,,,,,,take care
Paul

 

[Simonh]

lookslike classic overheated RB to me. Bags loads of det damage and a melted no6 piston, what were you doing for cooling? (both Air and water)

Simon

 

[SKiddell]

Oh well forged pistons it is .

Forged pistons alone will not prevent that from happening again unless the heat/detonation issues are managed correctly and that means a significant rethink on both air and water cooling.

 

[ZHead]

Reall sorry to hear about the piston melt - crap luck !

While you are rectifying the faults, it may be worth looking at a bigger radiator (radtech in cannock do a great one), venting the bonnet, venting the inner wings and any other mods you can do to reduce engine bay temperature - RBs are notorious for overheating.

 

[Zed2k]

Might be worth thinking about fitting water injection I think I'm going to go this route, how much boost were you running? I am running 11.5 psi boost at 22degrees no problems yet, I will be fitting bonnet vents over the weekend to reduce temps in the engine bay too!!

 

[GTR-240Z]

To improve the cooling I've got a new aluminium radiator, also looking to fit a belly pan and may fit a 2nd electric fan as the intercooler obstructs a lot of flow to the radiator. I'm also going to try to angle the radiator so I can scoop some air from the bottom of the car to overcome the lack of air due to the intercooler.
I will also be redirecting the intake pipework so it picks cooler air from the bottom of the car as they where previously right in the hottest spot of the engine bay.
I'll post some pictures of what I'm doing as I progress along.

 

[Ian Patmore]

Bummer. Good luck getting it sorted....at least you know how you plan to sort this out.

Excuse my ignorance, as I don't know much about RB's, but I take it the melting was due to not enough cooling around No.6, as by the time the coolant reaches here after picking up temp. from passing the other pistons it had lost its cooling potential? Is it possible to run a coolant by-pass hose along the side of the block and enter at the rear of the engine....a bit like by-passing the heater on a S30 with a L series engine and using the elbow on the rear of the cylinder head as a coolant inflow as well? Stupid idea?

Regards
Ian

 

[twoforty]

I had big cooling issues until I angled my intercooler out at the bottom to allow air to flow under and thru the rad.....didn't go over 90 at Japfest. I also fitted a plate from the spoiler to the bottom of the rad support panel to stop air flow under the car rather than thru the rads. Water wetter also helps. Could also fit a lower temp thermostat....whatever you do don't run it without one like some people do.

 

[SKiddell]

Before setting about redesigning the water jacket (Nissan engineers did a pretty good job) Its worth while looking at the causes rather than the symptoms.
Its not necessarily due to just water temperature/circulation. With a forced induction setup the "compressed" air feeding into the inlet tract is already warm, due to the "squeezing" action of the turbo/supercharger (Boyles law), under normal driving the intercooler helps shed some of this heat bringing the charge temp down (remember an intercooler is an air interface system and not a refrigeration system so they CANNOT reduce the charge temp below ambient) then add in the fact that you are drawing air into the system from an already warm engine bay (Z's are notoriously warm anyway) then the intercooler may become saturated and not be able to reduce the incoming charge temperature enough to prevent a detonation event (Darren’s pistons appear to show signs of "det") add in the possibility of under cooled water due to an undersized radiator /proximity to intercooler and hey presto aluminium croutons in oil soup.

Finally before excersizing the cars potential it must be rolling roaded to ensure that AFR is correct through the power spread and no sign of det etc is present.

Just my 2 pennys worth and meant only as an opinion

 

[Zed2k]

You are dead right Steve, it's the only way I am very concerned about intake air temps and engine bay temp in general, thats why I am going to go for water injection to help cool the intake charge, and fitting large bonnet vents,I also want to get mine rolling roaded to check all is good, also plan to run a Intercooler cooling system, maybe an overkill.. as soon as I read 300bhp at the wheels i'm leaving it at that.

 

[Ian Patmore]

cooling

Maybe Nissan did do a good job of designing the water jacket, but if you up the spec of the engine to get more power, you up the heat generated, you up the cooling to compensate, better rad. etc. and in-efficiencies may surface. Maybe taking the engine further than Nissan designed it. Why not other things to aid cooling... if you read Hybridz thread, in the cut and pasted blue box in the first post, it talks about detonation...I know its about L series heads/engines and a "cooling issue" in No.5 chamber on a particular L series head, but its relavent on cooling issues, which maybe could be transfered to a RB engine.

To me, if detonation occurs on No.6, then the cooling around it is not good enough, maybe its part of the reason. Better rad. thermostat/water wetter etc. all going to help. If inlet temps were too high from the incoming air, would not detonation happen in other bores/pistons?

Just my limited opinion/knowledge....


http://forums.hybridz.org/showthread.php?t=125186&highlight=coolant+bypass

 

[SKiddell]

Ian

All of the cylinders show slight det marks, the engine in question blew out on two cylinders not one.

but if you up the spec of the engine to get more power, you up the heat generated

agreed BUT this engine is fairly standard, running mild boost which is (no offence intended at all) modest in comparison with what an RB will do (6 and 700 hp RB's are not uncommon)

A stock internal RB with mildly uprated turbos, injectors, intercooler and pipework will piss 400+ HP

 

[twoforty]

His intercooler looks big enough to keep the air temps down low....Mines about the same size and after ragging it around the airfield it wasn't even warm to touch. Air temps stay at 10deg above ambient. I expect the air is stalling after the IC making the Rad nothing more than a hot water tank. Does you stock ECU have a diagnostic socket so that you could monitor air/water temps and lambda?