Manifold Curl?

SCLarry

Registered User
Has anyone heard of this? My car is currently at the shop having the HGs replaced. I just got a call from the mechanic and he said one of the manifolds has curled and they cannot get it bolted onto the head (the bolts started to cross thread into the head).

Now I was thinking about getting headers at some time, so this may not be much of an issue. If I get the headers, I will be buying them (not the shop), so the shop is not getting a cut and aren't really getting much extra money if I do.

I just haven't heard of this problem on our cars before.
 
I'd give them the benefit of the doubt BUT...90% of the time when something like this happens it's because somebody couldn't start the bolt by hand and grabbed an air ratchet and slapped the bolt in the socket and expected it to start itself in the threads. Kinda like the (LAZY) numbskull that puts a mag wheel lugnut in the socket of his impact and proceeds to expect the lugnut to start on the wheel stud all by itself...NOT.
Next thing ya know the stud & lug are toast and he's tellin' you your parts are the cause...NOT.

From experience, I can say that our manifolds are not molded perfectly concerning lining up with the bolt holes in the heads but when ya get down to the cause of a crossed thread there's only one reason...the bolt wasn't started properly.
Now if it's not actually cross-threaded but galled instead, then that's another story. In this day and age there should be a jar/tube of anti-sieze in everyone's toolbox and it should be used every time a carbon bolt meets an aluminum thread. Unless the installer doesn't know any better (90% of the time), there's just no excuse for galled threads (unless it happens on initial removal/disassembly).

At this point...If your mechanic can remove the manifold and the bolt goes in ok then fine...but if the hole/threads in the head are buggered up then he better get to work on chasin' those threads with a tap and then try installing the manifold again.

Headers aren't going to fix buggered threads in the head,

'bird
 
The way he was talking it sounded like it started to cross and then he backed off. I don't think he is rushing this job. I made sure to let him know I care more about the quality than speed. He seems to be taking that to heart, because he decided to work on it over the weekend when his shop is closed so nobody can interrupt him while he is working on the car.

He said the holes were off by about 1/8 inch. Which seems like a lot to me. And unlike most misaligned holes, you can't jam a screw driver in there to align the holes.

Also, are the SCP Kooks headers the only true SC headers? I don't want to mess with the mustang headers, I hear they need welding to mod them.

If I get the Kooks mid-length headers is there anything else I will need, or are they direct bolt ons? The exhaust is stock, but I plan on upgrading it in the spring. My hand may be forced now to get that done now.

This car owns me!!!!
 
1/8" is pretty drastic. Somewhere during its life someone might've washed the engine at a carwash before letting it cool enuff and stressed the manifold.

If it's the driverside manifold, see if you can borrow one off of another 3.8 to do a quick test for fit. Any 3.8 driverside will work. I port manifolds and have found no difference in driverside castings.
Only the passenger side n/a's are different from SC's because of O2 sensor location. N/A sensors are in the manifold instead of the downtube like ours but of course will work in a pinch if you plug the sensor bung.

'bird
 
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