Well, trying to take care of a header leak on the driver's side. see my prior thread.

Definite leak at the driver's side front port.

Loosened all of the header bolts down to the last few threads and retightened everything from the center out to 15 ft lbs..

Started it up. Felt what I thought was a slight puff of air at the front port but definitely much better than what I had started with, I took a ride of about 15 miles got back home, opened the hood and looked in the area of the first port.

Saw that tell tale very light trace of soot. Very light. I thought "thats as good as I can get it and decided to make sure that the bolts were at 16ft lbs after my ride. The torque wrench set to 16ft lbs.

Put it on that front header bolt gave it a slight twist and listened for the click and the release.

I got the release alright. Didn't think anything of it. Thought it was the typical release you get when the bolt is torqued to where you set it. Wrong was I. The head of that bolt fell right off.

Now the specs call for 18ft lbs. My wrench was set at 16ft/lbs just to give myself a margin of error.

Don't you know, that bolt snapped with that wrench set at 16 ft/lbs.

Apparently this is not the first time this has happened using a torque wrench!!!!!!!.

http://forums.corvetteforum.com/show...en+header+bolt

I pulled the header completely off and there is a bit of the bolt sticking out of the head, but not enough to grab. The bolts all have anti zieze on them and I tried to turn the remnant with a flat headed screw driver without any luck.

Oh well. I removed the gasket and it was a pretty good leak. The gasket had that stellate/sunburst pattern of soot on it too, indicating that a leak was present. I couldn't leave it that way.

The stock gasket is on it now and I will take it to an area shop to have that bolt remnant removed, hopefully without having to remove the head. But if it comes to that, then so be it.

 

Ughh - another good example of why headers are a PITA

 

Sorry to hear about this DSOM. It should be fairly easy for the shop to get the old bolt out.


Actually they couldn't be much easyer to install.
A couple of suggestions for those installing headers though:
Spend the $32 and replace the exhaust manifold gaskets with new ones. Irregardless of how many miles they have been used.
Tighten the headers starting from the front tightening towards the back/rear.

 

Can you get a drill bit on it? Enough to drill for an EZ out?

 

I had two broken exhaust manifold bolts on my old 94 Z28 a while ago. I could not get to the back bolts even with a right angle drill. Plus trying to drill out a hard bolt inside a nice soft aluminum head did not thrill me. Slip and you could start drilling into your head (not a good thing). You are doing the right thing taking it to a shop. I ended up taking off the heads of the Z and had them freshened up along with adding some Jet Hot coated Mac mid length headers.

I'm disappointed that the LG's leaked on you.

 

Nooooo. You need a right angle drill to get to it to put in the EZ out.

Fortunately its the very front header bolt. The only better one to have this happen is the middle bolt. You definitely don't want it to happen in that rear bolt.

The alternator might have to be removed, but probably not. A good shop should be able to get it out w/o removing the head.

As for the tightening sequence, and the torque wrench. This problem was self inflicted, so the headers PITA comment is unfounded.

I say self inflicted because I was so concerned about getting that rear bolt in, the one closest to the firewall, and not cross threading it, that I torqued it down too far, before I installed and tightened the other bolts enough, during the initial install.

I think this is what lead to the problem.

1. Memory is foggy but I want to say I started at the center and went out during the iinstall. But I recall being fixated on that rear bolt and repeatedly inserting it and hand tightening it several times to be sure that I wouldn't cross thread it. I may very well have tightend it well in advance of the others. This would have lead to a leak in the front.

2. Using a torque wrench to tighten those bolts and then using it before the bolts had a chance to cool after my last ride. The heat may have caused the metal to fatique and is possibly why it only took 16ft/lbs of torque to wind the head off of one of them. Tightening those bolts while they were still hot was a mistake.

I know how tight a header bolt should be and never should have trusted that torque wrench.

3. Actually, I was using the gaskets which came with the headers. These are better than the factory gaskets I just found out in between this and my last post. I just reinstalled the used gasket which came with the headers and removed the factory one as it was leaking like a siv. The aftermarket gasket is barely leaking so I can get it to the shop, no problem.

4. The folk over in LS1 tech mention copper gasket spray http://ls1tech.com/forums/showthread.php?t=560609
http://ls1tech.com/forums/showthread.php?t=558309 and Percy's header gaskets. These are said to eliminate stubborn leaks. I thought about ordering these through JEGS but decided to try and reposition the header and the existing gasket and see if that worked.

I had read this last night and didn't take it to heart.

5. This leak really wasn't that bad. But I am so ****, any leak was unacceptable to me. I had to eliminate it......At all costs.

Oh well, WTH. At least when the season gets here, it won't be a problem.

 

Part of keeping your cool about it, as you are, is knowing it's going to be allright.

 

Thanks, but its the only thing I can do. I can raise a fit about it, but at the end of the day, that piece of bolt still has to come out of my cyilinder head. One way or another.

Also that leak had to be tracked down and eliminated. So if this mishap occured in the pursuit of that end, then I'm OK with it.

I have been working on cars for much of my life and well, $**+ happens.

 

Sorry about your problems. Have you considered header studs instead. I don't even know if it is possible with the Vette but I know ARP sells a kit for the LS2. I have always been a bit squemish about torqing down bolts where aluminum is conserned. Plus the nice thing about studs is it is just about impossible to break them off.

 

Can you strip the threads with these? You overtighten into an aluminum head and it can strip the threads. Probably as big a problem as a broken header bolt.

Its always risky when tightening header bolts into an aluminum head.

You can either strip the threads or break the bolt if you are not careful. And even then bad things can happen. For example, I was using a torque wrench.

I have read other instances of people attempting to remove header bolts and breaking them off similar to mine. Nearly flush with the head.

 

I think you can cross thread or strip out anything. It is just harder with studs. The stud goes in with just your fingers. When you torque them down you normally use less force because it apllies a clamp force, pulling as well a pushing. I'm sure someone can explain better than I.

Here is a link for the ARP studs for the LS2. http://www.thunderracing.com/catalog...d=663&pcid=301

 

Its great that install is relatively easy, its just that headers crack, leak, etc. - unfortunately I've yet to see any as durable as the good ol' cast exhaust manifolds.

 

Having grown up with mild steel headers (that only cost about $150 ) that leaked, rusted, scraped, you name it, I used to feel the exact way you do. Matter of fact I noticed one of my old cars needs a set of gaskets last weekend. It's been about 2 years so that's about right.

These mucho expensive stainless headers and the excellent mls factory gaskets don't typically leak (unless there's an install problem), or need any adjusting for the life of the car. They're made much better than our old stuff. Somebody told me that back in 2002 and I didn't believe him, but he was right. All my buddies and I run headers trouble free for years.

I've put headers on several cars... I would think header studs would make it impossible, if not crazy difficult, to squeeze them up in there on a factory car. But I'd like to see someone try, if there's room to slide the headers in they would make the install a piece of cake!

 

Sorry to hear of your troubles, when I did the headers on my '99 I used an inch/pound wrench for the header bolts. I don't even think my foot/pound wrench even goes down to 16 ft/lb.

Best of luck getting it all taken care of.

 

Not trying to piggyback this thread but would it be a good idea to replace your header bolts (or put anti-seize on the ones in there) right when you take delivery of your C6 to make sure this never happens?

 

This is a great thread (sorry it was at your misfortune)

Seems best way is not to use a torque wrench, just snug them up.

One question, did you put a straight edge to the back of the flange on the headers to see if they have a slight warp or uneven surface? May be part of the cause of the problem and the leak ?

 

I would definitely not use a torque wrench. I have now heard of at least 4 cases between here and the LS1tech forum, including my own, where this has happened using a torque wrench.

Mine will go down to 10 ft/lbs.

I have gotten ahold of a shop that can get it out on Monday. He'll check the flange to make sure that it is true as well as the welds.

The interesting thing here is that this leak could not be heard very well, if at all, but after driving the car it could be "seen." In other words, the soot around the head in that area after driving the car. It could also be "felt". Tiny puff of air could be felt while you could still get your hand in the area before it got too hot.

I am going to pick up a couple new gaskets to have ready for Monday. Hopefully, Monday evening it should be done.

 

I know what you mean, but I had put antisieze on them already.

This happened when I was trying to tighten it as opposed to loosening it. Antisieze would be beneficial in either instance though.

I am still wondering how I broke that bolt. Did it bottom out? If so, why didn't it simply strip? Was the flange not going down as I tightened????? Or was it because I tightend it while the car was still plenty hot?

BTW, I looked at that bolt. Cheap pot metal. I'll take a pic of it if I still have it around.

 

Z51,

Man, I'm sorry to hear about your header bolt. I'm going to try and spearate my x-pipe from the header again this weekend (ceramic coated header issue from last week). I was thinking about your suggestion to unbolting the headers and drop the x-pipe/header assembly to prevent damage to the heads. Now I'm really confused as to what to do.

I snapped of 2 of the 36 bolts while installing the tunnel plate. Such a great feeling, right? Just like you described. Using a torque wrench set to only 7lbs. Well, best of luck to you and keep us posted on your progress.

ml

 

since that's the case, i'm not sure if this would work but since you've got antisieze on them and you're trying to get it out it just may. would a drop of superglue allow you to put the bolt back together enough to get it out ? i thought i read that the bolt broke outside the head but not enough to get a good grab on it with the visegrips.