Gman2004

iTrader: (8)

Todd how does your headgaskit look?

350zDCalb

iTrader: (21)

pretty much perfect mild residue on the outer perimeter of cylinder #3..that's it..oh, and coolant reside on the outside of the block where it pissed out

350zDCalb

iTrader: (21)

you could do that...may still not be definitive based on the fact that you wouldnt have a way to simulate the heat created in the motor in a real world situation

Gman2004

iTrader: (8)

Grrrrrrrreat!

booger

iTrader: (6)

Also ..I thought..you wouldnt have no where near the preasure in the cyl. as when boosting

350zDCalb

iTrader: (21)

The fact of the matter is...as more and more people run these motors hard, the other issues will show their ugly little heads...fortunately, the 650whp benchmark is pretty well figured out...it is surprising that you are having these issues at the lower power levels...what were your head studs torqued to? how many miles on the motor...possibly it is due to the fact that you were running continuous pressure for prolonged durations....

ultimately, for those of you wanting 600whp and beyond, we are recommending addressing the headlift issues with a few different options...
will keep you posted as more develops

TODD

MIAPLAYA

iTrader: (3)

I'm not trying to dispute anyone here but the issues have the same symptoms it appears. I would at the very least try the thermostat. If the issue goes away that was it. If it doesn't you are out a couple hours of time max.

350zDCalb

iTrader: (21)

could be, highly unlikely...you can definately test this, but the infrequency of early stage head lift may lead you to think you fixed the problem when the symptoms disappear with the thermostat swap.

again, good luck...I have learned to always plan for the worst...it has worked out that way, EVERY SINGLE TIME- and I'm going on motor #4

MIAPLAYA

iTrader: (3)

I understand what you are saying Todd but my point is that I had the EXACT SAME issues and it was just my thermostat and has not occured again since I remove the thermostat.

jpc350z

With 13psi boost + another 15 psi (atm) = 28psia and x 8.5 cr = 238 psi in each cylinder before the ignition of fuel which can be 3 or 4 x the 238 psi..Some where around 1000 psi in each cylinder...

Z350Lover

iTrader: (2)

GUYS.... before you change the thermostates, check the pressure at the radiator cap.... I had the exact same problem last week and calling for help on the forum... also... I am running full N/A setup (hardcore one, but not FI yet)... and it ends up to be the faulty radiator cap... I even lost my heater and had the reservoir tank filled up too and overheated without the gauge to come back down itself... I had to tow the car in... then when they checked for the leak and the thermostate, everything worked fine... then they filled up the coolant that day into the system.... I went for a quick yet hard drive, no over heating... but still my heater only works for a few minutes during my drive and around 2 minutes after my drive, then it stopped working again. When I came back home, i noticed that there was a huge hissing noise coming from the radiator cap and saw the nismo sticker on the radiator cap looked a bit funny, so I put the stock item back on... and filled the system up again, then I got the heater back from then and works great till now... nissan had the system checked and couldn't fault anything.. so they reckon it was the radiator cap too!

Good luck with that, try the radiator cap if you have that mod... my tuner told me that he returned 5 brand new radiator caps back to the supplier because they were leaking (don't wanna put down the name of those caps)... probably just pure bad luck here!

cheers,

richie

Z350Lover

iTrader: (2)

btw....

Please post all the symptoms of the head lifting problem here, they might help people out... and how will that happen actually? Thanks!

cheers,

richie

350zDCalb

iTrader: (21)

when the system pressurizes from a head lift problem, the spring in the radiator cap is compressed and the overflow tank fills up...in the early phase of head lift, when you depressurize the system (open the bleeder or remove the radiator cap) and then fill up the lost coolant, the head lift issue may not show itself for another several weeks or so...it is easy to convince yourself it was the fault of the radiator cap if you replace it and you don't see signs of head lift for a while...again, not trying to be negative, but I went through all of these steps..and ultimately, after enough time has elapsed, the problem reoccurs and you have to admit it wasn't the thermostat, wasn't the radiator cap, but it was and is cylinder head lift

booger

iTrader: (6)

Todd
I was off the dyno for a half hour and 3/4's the way home [ about 7 mile trip ] when my temp gauge spiked and came back down real fast . I never noticed it getting hot on the dyno . Im going to wait to do any thing till it happens again . To see if it does it under normal driving or does it after boosting hard .

overZealous1

iTrader: (27)

ya like todd says, the first time or 2 it is easy to blame other things. once it starts to happen though, it goes downhill pretty quickly. the first signs on my car was about 5-6 weeks ago. i have even been babying mine yet still have to carry 2 gallons of water with me as my temp gauge no longer gives me a warning. i have to drive with my heater on and when it goes cold, i know i need more water. i have mastered the art of filling the motor also now, so there is no chance a caught air bubble is the culprit. i also pulled my thermostat about 3 weeks ago to eliminate the chances that was it.

booger

iTrader: (6)

Well it I went out today and confimed the worst . I did several runs in 3rd gear up to redline and each time I looked the water level in the over flow tank got higher and higher . About a 1/2 inch more each time I looked .
Sharif...how many hours of labor does it take to pull the heads for new gaskets and studs ?


So no more boosting , till I get her fixed

MIAPLAYA

iTrader: (3)

did the car overheat? I'm still not convinced...

booger

iTrader: (6)

No...it didnt over heat at all .

MIAPLAYA

iTrader: (3)

OK I lose...sorry boog. Hoped it was that simple for you...

jpc350z

Any coolant water in the oil??