LG header install questions
Thread Starter
Instructor
Joined: Jun 2003
Posts: 102
Likes: 0
From: Columbia Md
LG header install questions
Let me start out by saying "I know I should be asking LG this question" but they aren't open right now so I figured I'd ask everyone else.
I am installing my LG headers. I got the headers in place no problem. All the header bolts were in about 5-7 turns (with antiseize) as suggested in the ls1howto.com guide. The bolts all seemed to go in fairly easy. Now when I tried to tighten them down they got really hard to turn. The recommended torque spec for the bolts is 18ft-lbs. It takes more than 18ft-lbs to spin these things even when they are a 1/4 inch out. I "measured" it with the toque wrench and it takes about 30ft-lbs just to turn them.
So what torque do I put them in with? If I did something terribly wrong what will happen when I start the car up? Will I throw lots of codes and have an exhaust leak at the header/head interface? Thanks for your help!
I am installing my LG headers. I got the headers in place no problem. All the header bolts were in about 5-7 turns (with antiseize) as suggested in the ls1howto.com guide. The bolts all seemed to go in fairly easy. Now when I tried to tighten them down they got really hard to turn. The recommended torque spec for the bolts is 18ft-lbs. It takes more than 18ft-lbs to spin these things even when they are a 1/4 inch out. I "measured" it with the toque wrench and it takes about 30ft-lbs just to turn them.
So what torque do I put them in with? If I did something terribly wrong what will happen when I start the car up? Will I throw lots of codes and have an exhaust leak at the header/head interface? Thanks for your help!
Melting Slicks
Joined: Sep 2001
Posts: 2,501
Likes: 35
From: Sunshine State, USA
Senior Member
Cruise-In V Veteran
Did you use the stock metal exhaust gaskets or the "soft" gasket sent with the kit. I found out the hard way you are supposed to use the stock metal gaskets, and the soft ones are only to be used if you have a leak. If you used the soft gaskets you will most likely have a leak. Also, did you reuse the stock exhaust manifold bolts? If so, they are probably bottoming out...I know this because mine did and I twisted the head off one. Do yourself a favor and get the locking stainless steel header bolts and you won't have any problems or any leaks. Do a search and you will find my post after I put on the very first set of do-it-yourself LG Pro Longtube Headers. They are great headers, but I made a couple of suggestions for improvements to their kit, but since you are asking these questions, I assume they didn't take my advice. 
Good luck!
Good luck!
Thread Starter
Instructor
Joined: Jun 2003
Posts: 102
Likes: 0
From: Columbia Md
I am using new GM ls1 gaskets. I could not re-use my old ones because they fell apart when I pulled them out. I am re-using my bolts. I dont believe the bolts are bottoming out since some of the bolts went in fine. I forgot to mention earlier that some of the bolts went in fine. I am having trouble with 4 bolts, not all of them. Also if I remember correctly these same 4 bolts were just as hard to remove.
Le Mans Master
Joined: Nov 2002
Posts: 7,179
Likes: 2
From: Charlotte, NC
Originally Posted by crom
I am using new GM ls1 gaskets. I could not re-use my old ones because they fell apart when I pulled them out. I am re-using my bolts. I dont believe the bolts are bottoming out since some of the bolts went in fine. I forgot to mention earlier that some of the bolts went in fine. I am having trouble with 4 bolts, not all of them. Also if I remember correctly these same 4 bolts were just as hard to remove.
Interesting.. if most of the bolts went in fine.. and a couple didn't maybe there is either thread sealer in those holes, or the threads are damaged from previous fastener install, or maybe there cross threaded in.. maybe an idea would be to get a tap in there and re-cut the threads on those holes.. clean out any crud or to just straighten un the threads.. just a suggestion.. last time I did LT headers on an LS1 I reused the stock bolts, and added a lock washer to the bolt too to keep it from backing out due to heating and cooling..
just my .02...
-Rick
Thread Starter
Instructor
Joined: Jun 2003
Posts: 102
Likes: 0
From: Columbia Md
I just backed one out completely. There was no debris that came out with it. I would think that if it were crosstheaded then some metal would come out with the bolt. When I put it back it, it went in much smoother. Any other suggestions?
Melting Slicks
Joined: Sep 2003
Posts: 2,458
Likes: 105
From: Northville Michigan
Matt,
Pull all of the bolts out and get yourself the appropriate size bottoming-tap. Apply some Aluminum cutting fluid and chase the threads in all of the holes to clean up the threads, remove any debris, and remove any damage done by previous installation of the fasteners. Also, check that none of the bolts are being restricted by rubbing on the side of the header flange bolt hole. If the bolts are rubbing on the header flange bole hole, take a grinder and elongate the offending holes.
Then apply a generous coat of copper-based anti-sieze and reinstall the bolts.
When I did my L.G. Motorsports header install, I purchased a set of ARP stainless steel studs, washers, and 12-point nuts. That made the installation very clean and easy. I am glad that I spent the $100 on the ARP studs.
Good luck with your install.
Pull all of the bolts out and get yourself the appropriate size bottoming-tap. Apply some Aluminum cutting fluid and chase the threads in all of the holes to clean up the threads, remove any debris, and remove any damage done by previous installation of the fasteners. Also, check that none of the bolts are being restricted by rubbing on the side of the header flange bolt hole. If the bolts are rubbing on the header flange bole hole, take a grinder and elongate the offending holes.
Then apply a generous coat of copper-based anti-sieze and reinstall the bolts.
When I did my L.G. Motorsports header install, I purchased a set of ARP stainless steel studs, washers, and 12-point nuts. That made the installation very clean and easy. I am glad that I spent the $100 on the ARP studs.
Good luck with your install.
Melting Slicks
Joined: Oct 2003
Posts: 2,834
Likes: 91
From: California
Originally Posted by Pumba
Matt,
Pull all of the bolts out and get yourself the appropriate size bottoming-tap. Apply some Aluminum cutting fluid and chase the threads in all of the holes to clean up the threads, remove any debris, and remove any damage done by previous installation of the fasteners. Also, check that none of the bolts are being restricted by rubbing on the side of the header flange bolt hole. If the bolts are rubbing on the header flange bole hole, take a grinder and elongate the offending holes.
Then apply a generous coat of copper-based anti-sieze and reinstall the bolts.
Pull all of the bolts out and get yourself the appropriate size bottoming-tap. Apply some Aluminum cutting fluid and chase the threads in all of the holes to clean up the threads, remove any debris, and remove any damage done by previous installation of the fasteners. Also, check that none of the bolts are being restricted by rubbing on the side of the header flange bolt hole. If the bolts are rubbing on the header flange bole hole, take a grinder and elongate the offending holes.
Then apply a generous coat of copper-based anti-sieze and reinstall the bolts.
Do Not force them in, you should be able to finger tighten the bolts at least 80% of the way in.
Le Mans Master
Joined: Nov 2002
Posts: 7,179
Likes: 2
From: Charlotte, NC
Originally Posted by crom
I just backed one out completely. There was no debris that came out with it. I would think that if it were crosstheaded then some metal would come out with the bolt. When I put it back it, it went in much smoother. Any other suggestions?
Just had this thought.. to check the depth of the hole.. take a paper clip or something and see where it bottoms in the hole then compare to length of the bolt/header thickness to ensure they are not bottoming out in the hole.. just an idea to kick around..
-Rick
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Drifting
Joined: Oct 2003
Posts: 1,540
Likes: 0
From: bloomfield nj
crom-are you trying to put the header bolts in with the x pipe attached or the headers mounted to the bellhousing?if you are STOP now or you will pull the threads out of the head.when i put mine in[lg's],i modified the installation a little bit.if you attach the headers to the bell housing then to the heads you will be trying to bend the header[the headers need to take a set].bolt up the headers to the heads THEN attach them at the bellhousing[you may have to pry the right side over a tad to bolt it up].once the car is started after the install,the headers will take a set.just my .02
Thread Starter
Instructor
Joined: Jun 2003
Posts: 102
Likes: 0
From: Columbia Md
I am going to get a tap from work on Monday and have a knoledgable friend help me re-tap the holes. I am also buying new header bolts. I'll let you all know what happens. Thanks for the input.
Burning Brakes
Joined: Oct 2001
Posts: 834
Likes: 0
From: Grayson Ga.
Originally Posted by dpd
crom-are you trying to put the header bolts in with the x pipe attached or the headers mounted to the bellhousing?if you are STOP now or you will pull the threads out of the head.when i put mine in[lg's],i modified the installation a little bit.if you attach the headers to the bell housing then to the heads you will be trying to bend the header[the headers need to take a set].bolt up the headers to the heads THEN attach them at the bellhousing[you may have to pry the right side over a tad to bolt it up].once the car is started after the install,the headers will take a set.just my .02
100 % same deal happened to me.
Safety Car
Joined: Nov 2003
Posts: 4,969
Likes: 2
From: Lake Worth FL
St. Jude Donor '03-'05-'06 & '12
Originally Posted by Pumba
When I did my L.G. Motorsports header install, I purchased a set of ARP stainless steel studs, washers, and 12-point nuts. That made the installation very clean and easy. I am glad that I spent the $100 on the ARP studs.
Melting Slicks
Joined: Nov 2003
Posts: 3,396
Likes: 2
From: North Manchester Indiana
Originally Posted by dmtnt
How did you install the studs? What torque spec for the studs and nuts? Anti-seize, loctite, etc? I had posted these questions recently but no-one helped -> http://forums.corvetteforum.com/showthread.php?t=858666.
