Blown Head Gaskets

supertbird89

Registered User
I have an 89 t-bird supercoupe with some engine modifications. I have an 70mm bbk throttle body, proted heads and intake manifold, kook shorty headers with down pipes, 2 1/2 exhaust, supercharger pulley, spec 6 puck racing clutch and 11.5lb flywheel, 3:55 rear end gears, adjustable fuel pressure regulator, 38lb injectors, 75mm calibrated mass air flow sensor ,and 255lph fuel pump. And before i had put all these parts on i blew the stock head gaskets, both of them. So in tearing the heads off, i thought i would had some performance parts, so i figured it also wouldn't hurt to through some 99 mustang fel-pro 3 layer steel head gaskets on. And with in less than 200 miles i blew them and i mean between the cylinders i am missing about a quater of an inch. And on this second tear down i noticed that the head bolts on the outer edge of the head, the bolts were alittle easier to break free than the ones under the valve cover. And the guy i bought the car from had told me that the ecu had been chipped, havent looked yet to see if it is, but i was told that the early chips made for the SC messed with timing a lot. So i was thinking that under boast when timing is already advanced could this chip be advancing timing even more causing extreme cylinder pressures, which happens under a lot of advanced which would cause the head bolts to strech and let me keep blowing head gaskets? And what would be a could head gasket to run? And is there a good chip out there to maybe allow me to tune the engine alittle bit? And so i just ordered some ARP head studs to help the bolt streching a bit. PLEASE HELP
 
I was actually just told earlier today that the JET, hypertech and those types do advance the timing and may possibly lean the engine out a bit. I was told to get rid of the chip. When you get it back together, run it on a Dyno with a wideband O2, so they can graph the A/F ratios, and make sure you aren't running lean. thats what i was told... sounds fair enough to me.
 
MLS gaskets don't work very well unless the deck is very flat and is smoother than stock. The heads also need to be resurfaced to a very smooth surface finish (like glass). The studs are a good idea, and yes the chip may be adding too much timing, especially if it's a generic.

I would get the heads resurfaced and go back together with stock felpro blue stripe composite gaskets.

David
 
if adding a wide band where do you put it since the is two bungs already in use in the headers for the O2 sensors? should i just get another bung and then weld it in where the exhaust goes down to one pipe after the resisenator? and the heads had been resurfaced i have checked the block with a stright edge and feeler gauge and it looked fine but i got a machinest square on the way.
 
i just pulled the ecu out and it was chipped with a JET power control module? anybody know anything about them good, bad? any way i dont think that holding the chip in with scotch tape around the whole ecu is a good idea either.
 
Supertbird89, pardon me for asking the obvious, but you're new here, so I don't know your level of experience with these cars. So here goes:

Did you use new head bolts after the HGs blew the first time? You can't reuse stock ones, or the regular Fel-Pro ones. They are torque-to-yield type bolts and they stretch irreversibly when torqued.

And, like Dave Neibert said, you are supposed to get the block and heads resurfaced to uber-fine smoothness in order to use MLS gaskets.
 
Yes the heads where machined and the bolts were new i am an student for automotive technology. I did all the proper steps in the repair. I am wondering now what head gaskets to use? Stock or the 99 mustang MLS made by fel-pro for both? The chip is why i am almost positive now why i blew the gaskets.
 
These are the 99 mustang Fel-Pro MLS with 200miles


shoebox.msnw

shoebox.msnw

shoebox.msnw

http://www.msnusers.com/blowingheadgaskets/shoebox.msnw?action=ShowPhoto&PhotoID=4
 
Yank the chip and install felpro composite gaskets...the MLS gaskets are going to keep leaking using a stock block surface. If you do insist on the MLS gaskets, install a set of ARP studs and tighten them down to 90-95 ft. lbs using moly lube.

BTW, you didn't follow the proper procudure or you wouldn't have used those MLS gaskets without first redecking the surface of the block. It must be smooth and more importantly it must be flat. The heads should also be resurfaced (smooth as possible).

David
 
The heads once agian had been resurfaced and the block was checked and was fine also used feeler gauge and perfect. What about the ford mls gaskets?
 
supertbird89 said:
The heads once agian had been resurfaced and the block was checked and was fine also used feeler gauge and perfect. What about the ford mls gaskets?
I think what David N. is trying to tell you is that BOTH the HEADS and BLOCK need to be resurfaced when using the MLS headgaskets. If you do not pull the motor and have it resurfaced prior to using the MLS gaskets they will not seal properly and are likely to blow again. The heads and block not only need to be flat and straight, but they need to be VERY smooth for the MLS gaskets to seal.

Just get the felpro blue stripe composite gaskets and get rid of that JET power control module as David mentioned earlier. Either that or (if you insist on the MLS gaskets) pull the engine and get the decks resurfaced as smooth as the machine shop can get them.
 
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