Heads lifting under boost? or blown headgasket? x5

[Yellow302]

So after 7 months of not having a car ive gotten it back together.

Now after driving around. My overflow tank is being filled and over flowing. This was after getting on the car hard a few times.

Im thinking boost is getting into my coolant system.

Luckly so far there is no water/oil mix nor am i burning anything that i can tell.

The car is still drivable in normal driving.

After doing a few searches it looks like the heads are lifting up under boost causing air or exhaust to get in there? Other than that it looks like a radiator cap issue.. i dont think so..

So the reason i didn't pull the heads off this engine was because it was fine for the 80k miles before i got it from the junkyard.

Any other possibilities?

If the heads are lifting under boost... what are my options.

 

[TrueBlue95GT]

I seriously doubt the heads are lifting from the block with only 8lbs of boost. It's most likely a blown head gasket. while the car is running and before it is up to temp, open the radiator cap and watch for small bubbles.

 

[Yellow302]

ill take a look, honestly i am done with modding my car, it has cost me nothing but time and money and it hasn't been right after 2 years, car afford the down time.

Now even with a new engine not 2 weeks and blow head gaskits... never using a blower again.

 

[Stanger007]

Yup the head gaskets are blown, higher boost is pushing combustion pressure into the coolant system.

If you choose to go back with new head gaskets I would recommend ARP studs and Felpro 9333-PT1 head gaskets.

Wes

P.S. And a tune.

 

[Yellow302]

Yup the head gaskets are blown, higher boost is pushing combustion pressure into the coolant system.

If you choose to go back with new head gaskets I would recommend ARP studs and Felpro 9333-PT1 head gaskets.

Wes

P.S. And a tune.

did studs and gaskets... 4 times... they never hold together... is there some break in period or something?

 

[Stanger007]

That's where the tune part comes in. :-D

Wes

P.S. I'd shoot for 11.5:1 AFR and 16* timing to start.
P.P.S. Make sure your heads and block are flat as well.

 

[Yellow302]

if im going this route again, cant i just o-ring the heads and be done with this?

 

[Stanger007]

if im going this route again, cant i just o-ring the heads and be done with this?

Want to shoot me a copy of your MTF file? I'll look it over and see if anything looks strange.

Wes

 

[final5-0]

Do you have a way to see your fuel and spark during WOT?

Grady

 

[Yellow302]

ill shoot you an e-mail soon, files are in my laptop not my pc.

 

[Yellow302]

Do you have a way to see your fuel and spark during WOT?

Grady

fuel yes, spark. no

 

[OrangeMustangGt]

make sure you are max 15 deg btdc advance and 11.5:1 to start at wot

NOW....

My combo that worked GREAT after changing 4 sets of headgaskets at 10 psi:

ARP studs...Top bolts torqued to 90 ftlb
bottom bolts torques to 85 ftlb

CLEAN CLEAN surfaces , then FELPRO MLS gaskets...Ive even gotten bad gas and A LARGE KNOCK and it still hasent let go....stockers would let go before you even heard anything.

 

[speedytang]

I would say if your having problem with 8psi and your keeping your timing under 21 degrees at WOT and have a large enough fuel pump then you are off on your tune and are detonating. I use cheap graphite head gaskets and run 14psi with 91+ octane. I would not O-ring anything since you are having problems at such a low boost because instead of changing head gaskets you will be replacing pistons.

 

[ProKiller]

i would agree to not o-ring the block. you'll just keep the gasket in place and force the pressure to the next weakest link which in our blocks is the hypercrap pistons.

i'd go with either the fel-pro or cometic MLS gaskets and studs with 90 on the top and 85 on the bottom bolts. take the heads to a machine shop to verify 100% that they are flat.

 

[legalize420]

i would do a compression test before anything else. also check the thermostat. could just be a problem with the cooling system.

 

[revhead347]

if im going this route again, cant i just o-ring the heads and be done with this?

Hell yeah, now you're on the right track. O-ring the heads and run Felpro factory replacement gaskets. I've blown one head gasket in 12 years with this setup. Best part is, it's $13/gasket. I know what you're thinking, yeah, I did blow a head gasket, but that's with aluminum heads, and 490/635 to the wheels. I honestly think my Felpro 1262 intake gaskets cost more than my head gaskets do.

Kurt

 

[Yellow302]

i would do a compression test before anything else. also check the thermostat. could just be a problem with the cooling system.

true, could be... im not burning anything or loosing coolant anymore