I have a forum members 1982 in my shop for upper and lower manifold gaskets. While i was in there i ported the manifold intake ports to enhance flow.
Here is the nightmare. After reassembly, i fired up the car. All was good while i was dialing in the timing. Car was running about 2 minutes. All the sudden this very loud knocking came out of nowhere. It sounded like a bolt was dropped in the motor. Then came the white smoke. I quickly shut down the motor.
Here is what i found. On the underside of the upper manifold there is a tapped hole in the casting with a block off screw to fill the hole. It appears to be a mistake that was made when the machining operation originally took place on the manifold. Either that or it was a mistake on the design end. In any case there solution to this was to put a allen head block screw in there to plug the hole. Then as there idea of a saftey procaution to keep the bolt from loosening, and falling back into the motor. They put a large heap of weld over the screw head. The weld was very crappy. Long story short, what happened was the weld poped off after retorquing the bolts. It was like a bullet bouncing around inside the motor.
I had myself, and another engineer friend of mine document what happened. I also have a friend who is an expert in aluminum welding. He was actually employed by NASA to do the tig welding on the first space shuttle. Who better to examine this weld? He will be coming by my shop in the morning.
I need to know if this was a one time screwup. Or did GM release other cars with this flaw?
I have not yet contacted the owner about this yet. I am hoping he will read it here first as i dont have the heart to tell him personally! :nonod: This guy really loves this car. And for good reason. It only has 27,000 original miles. It still smells new inside. It is also one of a hand full of cars to leave with it's blue paint. It is a nice ride!
I really need to hear from you crossfire experts regarding this. It seems to me he should have some recourse leagally with GM? :U

 

Go to this web site and ask its all Crossfire. I've never heard of what Your talking about so I don't think its a built in flaw. http://www.crossfire.webhop.net/

 

that is definitley not factory, some goober tried to fix his mistake

 

I think that it is like that from the factory.

Is the plug straight below the fuel pressure regulator on the rear TBI?







I suspect that they assemble the lid with the TBI's, adjust the fuel pressure thru the access hole, and then weld the allen plug in place.

 

So it is an access hole? That would make sense.

 

oh yeah...mine has that, i guess with a picture it made more sense..

 

I doubt that hole was used to adjust fuel pressure. It may have been so long since you removed it, Jonas, that you forgot, but the regulator has a plug in it that would prevent adjusting the pressure, even through the lid hole. Unless, of course they could plug the regulator from under there too.

All of this speculation is of little solace to sdixon, who STILL has to break the news to the car owner. Good luck going after GM, 20 years later.

 

I still have that plug installed. I think that it is possible to install both plugs with the TBI monted to the lid.

IF the adjusted the fuel pressure at the factory then I don't think that they disasembled the TBI afterwards to install the plug in the regulator. That means that they must have been able to install the regulator plug thru the hole in the TB under the regulator. If they could do that then they could install it thru the access hole in the lid too.

 

no kidding!