So, I took GB out to play one evening. I'm on a nice straight, flat, desolate strip of road out in the middle of nowhere. I stop the car. I rev the engine a few times, then floor it. The engine springs to life, the wheels start to spin, and then I hear it .... a "thunk" as something hits the undercarriage, another "thunk" as whatever it is hits the pavement, and at the same time, instant exhaust leak sound.
I say to myself, "Darn, the collector bolts loosened again, and one popped out."
I only wish it were that simple.
What happened was a piece of the passenger side header blew out, and I had a quarter-sized hole in the top of one of my header pipes:
The rest of the header is fine - no cracks or fissures or corrosion, and the driver's side header is fine.
I called Kooks to tell them and find out if there was any recourse. They told me to provide them with a picture and a copy of the original invoice, showing that I'm the original purchaser. Well, there was no way to get a picture until a bunch of stuff was removed from the top, or until the header was removed, so I started that process. In subsequent conversation with Kooks I found out that they no longer make the T-bird headers, they sold the flanges and jigs to another company. I also found out that they will "repair or replace" at their discretion, and they only warranty their stainless steel products, they don't warranty mild steel headers. They also do not re-coat the repaired or replacement headers - the costomer has to pay for that. The rep couldn't really tell me what would happen if a replacement was necessary, since Kooks no longer has the flanges or jigs. That question is moot, anyway, since my headers were made from mild steel and not under warranty (I don't think they offered them in stainless). I'm not complaining about Kooks, mind you, I'm fully aware that it's part of the game with a highly modified car - stuff just is what it is, and you gotta pay to play. I'm merely passing on information I learned.
So, what to do? what to do? Here's what I did:
So, what caused such an unusual type of failure? My exhaust guy and I scratched our heads for awhile trying to figure out how it happened. Then we figured it out (we think).
Yep, that's it. The evaporation drain from the air conditioner. I'm sure most of the guys with Kooks headers noticed that the A/C evaporation drips right on the headers. I know I noticed the periodic "hiss," figured out what it was, and, thinking only about rust potential, said to myself, "No problem, the water instantly turns to steam, and won't be on the tube long enough to rust it." I actually thought it was kinda cool (literally) that I could sit on line at the track with my A/C on, and no one would know or complain, 'cause no water ever leaked to the pavement.
What I failed to consider is that the process of evaporating the water cools the metal, if only for an instant, then the metal reheats (expands), then cools (contracts), then heats, etc. - over and over again, every time I run the A/C, which is most of the time in Florida. This constant expansion and contraction, only minute, but confined to this small, concentrated area must have caused stress fractures in the metal, and eventual failure. This explains why the failure is only on the passenger side, only in the one place, and would explain why the hole is nearly perfectly round. The evaporation water hits the tube and spreads out in a circle, only so far before it evaporates off the tube. Of course I'm not 100% sure, 'cause with the headers out, I can't really tell if the hole is in the exact spot where the evaporation hit, but it seems to be. At least that's all I could figure out, if someone has another explanation for the failure, feel free to chime in.
To prevent it from happening again, I'm gonna attach a 3/4 inch ID hose with a 90 degree bend to the evaporation drain and route the water elsewhere.
Removing the passenger side header from GB involved much "weeping and gnashing of teeth." With the aftermarket valve covers and all the intake plumbing, there is no way to get to any of the header bolts from the top. So, the front suspension had to come out along with the K-member, while we supported the motor from the top. Then, we had to raise and lower and tilt the motor from side to side, and remove the A/C dryer and variouse hoses to get to all of the header bolts. It did not help the removal that the bolts are Stage 8's, and they won't be easy to clip back in, but they are the only way to go.
If they haven't already done so, anyone with Kooks headers should consider re-routing that evaporation drip. Just sayin'