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. For starters 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


[Modified by sdixon, 12:24 AM 4/27/2002]

 

If Twinnie doesn't chime in here then you can go to his crossfire forum
http://www.crossfire.webhop.net/
There is alot of people over there that know the CFI from top to bottom...

Good luck

:cheers:

 

All CFI lids have that plug!
It's this one you mean right? (the one on the right, what you see here is a hacked up swirl plate.. for those wondering what it is)


I'm not sure what the thing is for but it is probably some sort of vacuum port that was scrapped in the design. Maybe GM used it for who knows what. I have never seen a CFI lid that did NOT have the plug!

This is the 1st time I heard one fell out.. really strange, the welds on it are actually quite sturdy and I can't imagine them breaking unless someone tried to unbolt it and gave up, partially breaking the weld.

Marck


[Modified by Twinnie, 4:06 AM 4/27/2002]


[Modified by Twinnie, 4:09 AM 4/27/2002]

 

Well i brought the owner over to my shop. I walked him through what happened. He took it surprisingly well.
It just goes to show that must corvette owners are damn good people.
I believe that i recovered must of the pieces of the weld. However, I think it would be wise to go ahead and pull the heads.
This way if there is anymore , I can catch it before anymore damage is done. i dont believe this was an access hole.
There is nothing to access on the top side. It appears to be a design mistake.
This was a real bite in the butt. I had that car purring like a kitten. And then wamo! What a waste of alot of hard work.
I will keep you guy's posted on what i find down in the cylinders. Hopefully nothing :cry

 

Twinnie, i was just looking at you photo. This weld was nothing like yours. It completly covered the fastener. And it was a very rough looking weld at that. This car only has 27,000 miles on it. It does not appear to of ever been opened. I think someone on the assembly line was just having a bad day :cry

 

Hey everybody....I'm the owner of Scott's nightmare :eek: Just wanted everyone to know that so far Scott has been doing everything to make a bad situation right. Scott--FYI--all will be forgiven when shes back on the road again. :yesnod:


[Modified by Gary Christensen, 7:50 AM 4/28/2002]

 

What happened exactly? did the welding material fall into the engine or the entire plug? If it's the plug it would have to 1st break the weld and then unscrew and fall down. A highly unlikely thing to happen but freak things happen now & then.

Gary I hope you will have some luck, not too much damage and that the car will be driving again soon!

If I had to say it, I'd still say someone tried to unscrew the plug at some time!

Marck

 

The plug did not move. I had the weld inspected. It was a really crappy job. It popped off when the manifold was be torqued down.
It had never been tampered with. There was no sign that this motor had ever been opened.