HELP - Header Bolt Missing

patrija · #1 (**permalink**) 10-19-2001, 05:34 PM

I've read through all the posts I can find on the topic, but thought I'd ask the question anyway.

I have a Southern Automotive 406 and the top header bolt on the Number 8 cylinder is missing. My cylinder numbering maybe off (newbie) ... it's the cylinder closest to the firewall on the driver side. At idle, when I run my hand along the header there is quite a bit of hot air (exhaust) coming out ... and yes, I did get a burn on my hand! It's starting to turn the paint, so it's obviously quite hot.

During deceleration while in gear there's a bit popping in the pipe. When I engage the clutch the popping minimizes. At idle there is a "clanking" at the cylinder / header. Here's my questions:

1) How the heck do you get to that top bolt??? There is no room!

2) Does the "clanking" at idle make sense with the bolt missing or perhaps indicating something else wrong?

3) Is it "safe" to drive without the bolt without damage?

Thanks!
Jason

Monster · #2 (**permalink**) 10-19-2001, 07:34 PM

Jason,

1) How the heck do you get to that top bolt??? There is no room!

>First WAIT TIL IT COOLS DOWN

Now,while I don't have a Unique, I believe that if it's that close you may have to cut a hole in the footbox to get that bolt in. I know that, that's been recomended to me for my car if I need to get those bolts off.

2) Does the "clanking" at idle make sense with the bolt missing or perhaps indicating something else wrong?

>Don't know this is hard to identify without hearing it, loose header?, cracked header or flange?

3) Is it "safe" to drive without the bolt without damage?

>Probably not a good idea, this can cause a burnt valve, exhaust fumes in the passenger compartment, maybe a long shot but even fire under some conditions. Better to take care of this ASAP before you find out what could happen.

good luck,
Mike "monster"

patrija · #3 (**permalink**) 10-19-2001, 07:42 PM

Mike

Thanks for the advice. I've been out in the garage all night and no luck so far.

Once it cooled down, it was quite a bit easier but no dice on figuring out an easy way to access it. I found the allen wrench (hex head) size that fits the other bolts, but I'm not sure what size bolt it is.

I'll do some more looking, but looks like I'm out for the weekend. :-(

Jason

Steve Dickey · #4 (**permalink**) 10-19-2001, 08:35 PM

Jason,
For what it is worth I'm holding an exhaust head stud for a 427mr head. The half that threads into the head is a 3/8"-24 , the other half is a 3/8"-16. I suspect it is the same as yours. If not, a good starting point. You may want to try heating up a wrench and bending it to fit around your foot box if you don't want to cut a hole in your box. Anyway you slice it, it is a bear to get to.
Good luck, Steve

aeroace · #5 (**permalink**) 10-19-2001, 09:14 PM

They can be challenging. It takes extreme dexterity and patience. If the header bolt is yoo long to fit in the hole, use a shorter bolt, like 3/4" not 1". You may need to use an angle wrench, where the openeing is offset to the side. You may be able to get them from the bottom side of the car, jack it up and get underneith it. Use your other hand sometimes. If there is NO ROOM get the engine hoist, hang the motor, disconnect the motor mounts, and push the engine over to gain the room. You'll also want to replace the exhaust gasket at this time; as the gasket around the port in question has been burned up. if you cac hear and feel the exhaust leak, the gsaket is wasted. don't completely remove the first and last bolt campletely, Just loosen them. The new gaskets will have notches to slide them in.

427sharpe · #6 (**permalink**) 10-19-2001, 10:01 PM

I have a tight fit as well, and found that studs are much easier to handle--install is much easier, and just use a hi-temp nylock to hold the header--they will not back off like a normal bolt. Take care of this ASAP--can cause a burnt valve very quickly! You may have to loosen up the motor mounts and raise the motor slightly.

poorboy · #7 (**permalink**) 10-20-2001, 05:28 AM

Jason;
If the header leak is causing the paint to discolor you should not drive it until repaired. The bolt is 3/8x16 and can be replaced with the engine left in place, sometimes from under the car. It sounds like the gasket should be replaced also. I have changed a few big block engines in Uniques cars so I know of what I speak. I find a standard hex head header bolt is eazier to put in than a allen headed header bolt. Just take care to starte it stright, in tight spots they cross thread eazy. Good luck

Poorboy

PS. Make sure to check all the bolts on the other side also. Header bolts are bad to work loose.

patrija · #8 (**permalink**) 10-20-2001, 06:49 AM

Thanks everyone ... I knew it shouldn't be driven in my brain, but my right foot needed to be convinced!

Sounds like I have a project for today or perhaps just hold until I get down to see Bill at SA. Since I just got the Cobra last week and have grown up more a driver than a mechanic, I am VERY lacking in the proper garage tools.

What's a laundry list of things I should be looking at to get started on this type of "standard" repair? I sure as heck can't turn those bolts with the small allen wrench I have!

Thanks again!
Jason