Header bolts backing out... solutions?

SadbutTrue

SadbutTrue

Founding Member
May 1, 2002
2,390
4
49
Granada Hills, California
#1
Since I got my car running a few weeks ago, I noticed a bad exhaust leak develop last week. It came on pretty fast... the car hasn't been running long, and once the leak became audible it went from barely noticeable to intolerable within... well, the same drive.

So I check yesterday and two of the header bolts had completely backed out, they were virtually all loose, and a few more woulda fallen out if my header pipes didn't make it physically impossible.

I've tightened them down as much as I could but I have to think they'll come out again.

First, I'm sure part of the reason this happens is because of alumnimum heads expanding more than normal ones, so while its running they're probably pretty loose...

Are there any bolts that are a bit better at staying with alumnimum heads?

Is it advisable to use any sort of loctite or thread-locking compound to keep them in place? I really don't want to have to tighten my headers every 50 miles...

Thanks
 
#5
Is it the bolts backing out or are yuo using cheap header gaskets and they're shrinking? I've got Percy's aluminum gaskets on both mine and after 1 or 2 retightenings, nothing else has been done. No locktite on the bolts. They do have antiseeze on the threads.
 
#6
k, I'll get some grade 8 fasteners and replace em as they pop out. i do have one ARP bolt on mine and did notice it hadn't backed out much (i believe they're grade 8+), so that should solve my issue. Will the local hardware store have grade 8 bolts that will be the right length/size or should I just get an ARP bolt setup? Anyone know the thread size/style offhand?

are you not using loctite because its not necessary or because its a bad idea? I really, really don't want to retighten these bolts again for a while so if a dab of something will do the trick (and not hurt anything), I'd be willing to try it.
 
#7
D.Hearne said:
Is it the bolts backing out or are yuo using cheap header gaskets and they're shrinking? I've got Percy's aluminum gaskets on both mine and after 1 or 2 retightenings, nothing else has been done. No locktite on the bolts. They do have antiseeze on the threads.
Click to expand...

I reused my old header gaskets (they seemed fine..). Probably could have gone with some new ones I guess. But with the iron heads I never had an issue like this.

I'm not sure how to tell the difference between them backing out and just having cheap header gaskets which are shrinking though. I would think its just the bolts backign out because, as I said, the gaskets themselves were never an issue before with the old iron heads. I believe they are aluminum gaskets too (not Percy's though).
 
#9
If the gaskets are aluminum sandwich types, then you should be fine reusing them. If they're composite/fiber types,(my use of the term "cheap" was a poor choice of words, no slam intended there) then them shrinking could be the problem. Never had an issue with header bolts as to different grades. I just use the off the shelf 3/8" headed ones. They will loosen with composite/fiber gaskets, but rarely so with aluminum sandwich gaskets.
 
#10
Also, if you're not using top-quality gaskets (I use Mr Gasket aluminums) then it's only a matter of time before the gaskets compress and the bolts lose their torque and you get an exhaust leak. Solid-type gaskets also help keep your flanges flat, but mostly they don't compress over time.
 
#11
#12
D.Hearne said:
If the gaskets are aluminum sandwich types, then you should be fine reusing them. If they're composite/fiber types,(my use of the term "cheap" was a poor choice of words, no slam intended there) then them shrinking could be the problem. Never had an issue with header bolts as to different grades. I just use the off the shelf 3/8" headed ones. They will loosen with composite/fiber gaskets, but rarely so with aluminum sandwich gaskets.
Click to expand...

Do they use any metal other than aluminum in header gaskets? Mine are definitely metallic, but its been years since I got em. (no worries about the word cheap).

What makes the stage 8 fasteners stick better than standard header bolts? I really don't wanna pay $60 for some tiny bolts if they're not gonna fix it (not tryign to be a punk here, just curious)

I was thinking it probably also doesn't help that, probably due to the headers/exhuast hitting speed bumps over the years, the exhaust doesn't perfectly line up with the headers and I have to tighten the living s*** out of them to get them to not leak down there. With the iron heads it didn't matter but i'm sure it was at least somewhat a factor here.
 
#14
D.Hearne said:
There were/are copper header gaskets too. You didn't use the metal composites made for manifolds did you?
Click to expand...

Nah they're not copper, they're silvery (unless its some strange alloy). And I don't think so, but its tough to tell. Actually have no idea where I got them... they've been on since I got the headers in 2004 or so. I'd take em off and take a pic, but I'm not excited about removing my headers enough to get them out... more of a job than I want to get into at the moment (but I'll obviously do it if nothign else works).

What do composites look like?
 
#15
"Stage 8" is the brand. They specifically made to be used on headers as they have a special locking design. Take a look at the link xoxbxfx put up earlier to see what the bolts look like.
I too am running a set of aluminum gaskets, so I would recommend that you look into a set.
 
#16
SadbutTrue said:
Nah they're not copper, they're silvery (unless its some strange alloy). And I don't think so, but its tough to tell. Actually have no idea where I got them... they've been on since I got the headers in 2004 or so. I'd take em off and take a pic, but I'm not excited about removing my headers enough to get them out... more of a job than I want to get into at the moment (but I'll obviously do it if nothign else works).

What do composites look like?
Click to expand...

Naw, don't take em off till you're ready. The composite metal ones are those that come in the engine gasket kits (Felpro for one) for stock rebuilds, they look like sandwiched/perforated metal one side, fiber on the other. Just me but when it comes to those Stage 8's, they may lock in place and not back out, but if you run em with common header gaskets and even the aluminum sandwich types, the headers are still going to leak when the gaskets get compressed over time. I'll bet you can still go in and tighten em up when this happens, even though they didn't back out. Their design just fixes half the problem.
 
#19
my recommendation is to use either the aluminum or copper header gaskets, and use a thin coat of copper coat rtv sealer on both sides of the gasket. that should end your leak problems once and for all. this worked great on the racecar that i crewed on years ago.
 
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