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Discussion Starter #1
Maybe a simple topic for the thoroughly versed engine techies, but it's new to me.

I'm thinking of taking my exhaust manifold off to gain access to more of the engine for a few things I'm doing. So the question is, can I reuse the gasket? I believe it's metal and it's not cheap at $48 to replace both.

Also, what are the chances of the manifold bolts snapping off as I take them out? I would not even do this if there is a good chance of them breaking as I take them out. As far as I know, the bolts have been on there since 1971. Time, water, rust, and heat have taken their toll.

Thanks,
Jeff
 

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Are we talking about stock cast iron manifolds or headers? World of difference.

Headers, you will be able to remove easily, but you should replace the gaskets.

Cast iron manifolds, there's a better than 99% chance the studs will snap off. Even if you soak them down, as you stated "time has taken it's toll" . The donut gaskets on those are usually in reusable condition. Not always.
 

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Discussion Starter #4
bummer

Are we talking about stock cast iron manifolds or headers? World of difference.

Headers, you will be able to remove easily, but you should replace the gaskets.

Cast iron manifolds, there's a better than 99% chance the studs will snap off. Even if you soak them down, as you stated "time has taken it's toll" . The donut gaskets on those are usually in reusable condition. Not always.
Yes these are the stock cast iron manifolds on a SB 350. If the bolt snapped outside the block, that's one thing, but if it were to snap on the inside, that would seem incredibly hard for me to fix. I've got some of the #8-32 bolts on the front grill cover that have snapped off and even those I'm finding are extremely hard to drill out, I can't imagine what those header bolts would be like.

What kind of torque are on those manifold bolts? I could always try and see if they'll come loose with a tiny bit of effort, and if not just leave it as it is.
 

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What kind of torque are on those manifold bolts? I could always try and see if they'll come loose with a tiny bit of effort, and if not just leave it as it is.
I think they're only around 45? ft lbs (don't quote me, but you'd think I'd know, I've had manifolds and heads off and on so many times....:smack)

Try P'Blaster on the bolts (better than WD-40), get a breaker bar if you don't already have one, a good quality 9/16" socket to go with the breaker bar. Let the Blaster soak in, (spray several times a day, for a couple of days), and try gently breaking them free using the breaker bar, in between Blaster soaking periods. Spray, wait, try to turn bolt, repeat.

Once you get them off, chase the threads in the block, replace the rusty bolts with new hardware, and put a smear of anti-sieze compound on the threads before you put them back in, (so as NOT to have this problem in the future).:thumbsup:
 

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30 lbs. ft. is the torque. Soak them well in penetrating oil and proceed with caution cause my inner two bolts snapped off and they were a bitch to drill and I wound up having to cut the manifold off in pieces. Sometimes you can get the manifolds warm enough to break them free as I had to do this on a couple of mine. Good luck.
 

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Discussion Starter #7
30 lbs. ft. is the torque. Soak them well in penetrating oil and proceed with caution cause my inner two bolts snapped off and they were a bitch to drill and I wound up having to cut the manifold off in pieces. Sometimes you can get the manifolds warm enough to break them free as I had to do this on a couple of mine. Good luck.
Wow, that's way beyond anything I want to attempt. I did try one with a regular socket and no PB and it came off pretty easy with not a lot of effort. I inspected the bolt and it didn't look too rusty, so hopefully the rest have been off at some point since '71. I suspect that if I have to resort to a breaker bar to move them, it might be a good idea to leave them alone. I don't think with the light pressure I put on that first one that I'd ever be able to snap anything unless the bolt was 3/4 rusted through.

Metalkid said:
I've had manifolds and heads off and on so many times....
Metalkid, with your manifolds being on and off so much, I'd imagine you've reused your gaskets at least once?
 

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My brothers 74 exhaust bolts came out easy and hardly had any rust on them. The main thing is to use good judgment and lube the bolts prior to removal.
 

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i would soak them in pb blaster just to be on the safe side
 

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I dont think there are factory gaskets there.After time tho the cast manifolds shrink & the 2 center holes may not ine up after removal.
 

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+1 on the PB Blaster soaking. Spray it on let it set and warm the engine up. Spray again, repeat the warm-up. About three times in 8 hours or so and the rust is usually melted where it rusts from the bolt to the manifold. I've never had much luck with WD-40 except that it smells good and is good at Water Displacement. That's where the WD came from.
 
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