Vas_Z33

iTrader: (39)

you have to remove our engine to do the HG right? ( never swapped or done HG on our cars )

quietkilla6

iTrader: (1)

probably should have waited until than to start a project like this.
ive mad bigger mistakes though... sorry to hear man. goodluck with everything.

binder

iTrader: (8)

correct sir

well, you can get it done in the car but it will probably take more time then just removing the engine. Getting headers out are a pain with the engine in the car. the time you take doing those would be enough to finish pulling it since the whole front end needs to be torn apart anyways. Maybe 30 more minutes to get hte engine out after all you have to remove.


Sylvan, i'm only seeing 12lbs of boost so maybe mine won't push coolant out and i can make this head gasket last til next winter when i get 3 weeks for christmas break.

streetzlegend

iTrader: (2)

Have you checked your spark plugs by any chance? They will be able to tell you more information as to what is happening or what happened, although since the car has been ran afterwards it might not be as precises but will still show some evidence of something happening such as detonation. Does your tuning device have any way to retard timing as knock occurs?

Now that i re-read your first post, it might be head gasket, there is no reason you should overheat like that. Changing the HG is not that bad, you can do it with the motor still in the car. I have done it on my maxima which has even more limited space.

Sylvan Lake V35

iTrader: (23)

I looked at doing my HG while the engine was in the amount of time it takes to pull an engine is minimal I can have mine out in an evening. The amount of frustration it would save would be well worth any additional time it took.


If your alternative is to go back to a stock engine... just turn the boost down to 6psi or less on this engine and take it easy till you have time/money to work on it it sucks but it might make it till Christmas like that.

Mine was odd when I was doing all of my checks ( leak down, compression and cooling system pressure) it was at my local "speed shop" I was discussing my results with the owner and his 4 techs that were there they all thought I must have just had an air bubble in the cooling system and they all have tons of experience with performance cars. Idling and normal driving it was fine so i thought it was all good till I made a few hard pulls. I would bleed your cooling system and go for a short drive staying out of boost and watch the coolant levels then try a few 6psi pulls, if it dosent push any coolant drive it like that. Or if you want to be sure if its the HG slightly warm the car up do 1-2 hard pulls and check the coolant overflow.

- bigc -

iTrader: (18)

was just looking at your cipher logs. what coolant temps do you typically see after a few WOT runs? you hit 213F per the last log, which, while high, isn't crazy high. the troubling thing is that your coolant temp increased twice as fast as it did in the previous runs (and the beginning of the final run).

this thread really bums me out - sucks cause of what you're going through and it also makes me even more paranoid about getting into boost

Dynosty

iTrader: (27)

A few comments:

- A loud pop is not typical of a head gasket blowing... this does not rule it out, but doesn't immediately make me think hg problem.
- Head gaskets do not always blow massively, as many expect. This means you may not experience the symptoms of coolant in exhaust, majorly mixed fluids, etc. It is possible to have a head gasket problem where the vehicle tests primarily fine and can be driven around under normal conditions without a problem. When placed under heavy load (high boost) it will seep again. If everything tests fine and you have bled the coolant, then the easy test is boosting it again. If you 'somehow' get air pockets in your coolant again... bad news.
- "Replacing" a head gasket often also requires the block and or heads to be decked. This is a major undertaking.

I truly hope that there is no head gasket problem on your car, and I don't mean to throw salt in your wounds - but this is exactly why spending money on a quality engine management and having an experienced/qualified dyno tuner is so worth it.

Zazz93

iTrader: (2)

Good points Hal@IP,

I unexperienced with FI, but 10:1 sound rich enough to deliver a mean backfire under the right conditions. Its also possible to get a backfire on the intake side, never witnessed this but have read about it. So if the pop sounded like it came from the motor side it could still be a backfire especially considering the odd things happening with the timing previously.

I'm with you on the leakdown test even though it may be inconclusive. If it goes well I think Hal@IP idea is the easiest way to confirm it.

Good luck!

Sharif@Forged

iTrader: (92)

I would start with a thorough purging of the cooling system, and followed by a leakdown test. Then take it for a test drive.

As Hal mentioned, oftentimes a HG leak isn't obvious and sometimes doesn't appear on a leakdown test. You will need to put the engine under some load to confirm.

rcdash

iTrader: (18)

Have heard about this, but (fortunately) never had to try it (and not sure how you do it without getting burned exactly):

http://www.arrowheadradiator.com/hea..._leak_test.htm

binder

iTrader: (8)

I built the engine and finished the car in november. I budgeted money for tune, hotel, and some small random things just in case. There was nothing more to do with the car therefore i didn't "undergo" the build when i was in school. I was making 60k a year when i started saving and planning. I have money, but i'm not stupid enough to spend money i might need for school and living expenses just for a car. Car budget is dead therefore i'm smart and keeping it dead. Taking money out of my normal fund is just asking for death sentence.

I would have to check. I only did a few runs before this went away for the winter and even then i wasn't pushing it so i don't really know what the engine temps move to. I know the needle on my gauge never moved so that's probably 20-30 degrees before that has to move over the normal operating temps. My oil temps were still under 200 but unfortunately i don't have those logged. I also had the car really rich with low timing which from what i've been told increases the combustion temps a lot. I was trying to keep it on the safe side and slowly add timing and remove fuel. Unfortunately the crappy tune from said tuner gave me a super high timing pull on accident (because i forgot to switch off his map back to mine).

It bums me out too.... trust me

Ya, i'm having friends do a comp test, leakdown, block test and radiator pressure test. If all those are negative then i'll put the beast into some hard boost runs when i go home in 3 weeks and see what happens.

After this weekend i'll probably be giving you a call to order some head gaskets and parts Hal. I'll also look into setting up a time for a tune. I do have my tax return i was saving for a rainy day and i can just "borrow" some cash from it since it won't affect my school and living expenses budget.

Sad thing is Hal, the tuner that i paid to tune my car is well known and has great reviews from everyone that has been to him. He had a TT g35 and another s/c g35 sitting there in the shop with mine (along with other cars). I would have never expected this from such a highly recommended shop. I'll disclose the info to you on the phone when i call. I'm not going to get into a huge tuner bashing thing online.

also, it's a MUST to redeck? I know that's probably the best and most correct way to do it, but that is a crapload of cost. Pull the block completely bare which means new rings and all that.


Thanks for taking a look at this Sharif. I agree about your and hal's advice.

streetzlegend

iTrader: (2)

redecking is only needed if the surface is not completely smooth, considering you dont have a completely blown head gasket, i doubt there is any warping, on the FSM there are procedures you can perform to make sure the heads are completely flat (just need a completely flat stick or ruler, as well as a filler gauge). I replaced my head gasket after almost 2 years of driving around with it leaking, didnt resurfance head or block, didnt have a single issue.

Dynosty

iTrader: (27)

It is not a MUST, but it is not optional either imo. Let me explain. It needs to be checked, and often times, will need to be decked. This is not like an old cast iron 2JZ with an aluminum head bolted onto it - rather it's two pieces of aluminum bolted together and heat cycled many many times. It may be possible to throw new gaskets in and use them to make up from the unevenness in surfaces... but you are getting lucky if so. I personally don't ever take the chance given how much labor is involved if I don't 'get lucky'.

binder

iTrader: (8)

i took your previous comment as meaning this. Better safe than sorry because if there is a problem it's a lot of labor to refix it.

So I would have to tear the engine down to a bare block and bare heads to get them redecked, correct?

With that amount of labor wouldn't it be cheaper to buy another short block? I could see it not being too bad if i do'nt have to remove valves, pistons and all that but i do'nt know how machining could be done with those in place.

Zazz93

iTrader: (2)

I was told the following on this motor by one of the factory techs, "do it as little as possible but whenever needed". On our engines, because it has a front cover that joins both block and head there is very little space to deck the block and head repeatedly. If you deck it too many times the tolerences can get out of whack, and if you don't resurface it when it needs it you don't get the sealing you need and you could have just wasted your time tearing it down and putting it together only to have a HG leak. Aluminum is relativly easily warped, and being this engine has aluminum for both the head and block it is possible to find a little warpage after a few thousand miles. So its best to first have it checked and decide accordingly.

streetzlegend

iTrader: (2)

Well if you take off too much material you can always get a custom headgasket made to make up for the loss clearance.

Zazz93

iTrader: (2)

True, but I'd rather not deal with the hassle if possible.

BrianLG35C

iTrader: (2)

What did the water/coolant temp rise to?

- bigc -

iTrader: (18)

213F

rcdash

iTrader: (18)

I don't think you're doing your pistons, headgasket or exhaust valves any favors running an AFR of 10:1 and timing of 10-12 degrees at redline at relatively low boost. As others have said, while it's impossible to rule out damage to the headgasket, most likely all the excess fuel just decided to explode in the exhaust manifold secondary to heat generated from the "retarded" tune. You say at the beginning that this has nothing to do with the tuner, but you're not that far from Hal@IP (authorized Osiris tuner), I'd take it down there and let him check it out and get you a tune that will prevent this from happening again.

EDIT: Just looked at the log you mentioned where the pop occurred. Man you were hardly on it - like 5% throttle going from like 50 to 60 mph? MAF was really low - had to be a backfire... Count yourself lucky that you got a warning - you can destroy any engine by retarding timing too much - get that puppy tuned by a pro and you'll be fine!