318 exhaust manifold bolts and nuts....

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firefighter1

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Hey guys,

I have a couple of questions regarding the installation and hardware of my 318 exhaust manifolds. First, what size and thread bolts do I need to buy to fasten the manifolds to the heads? Second, do I need sealant along with the gaskets in order to properly seal and install the exhaust manifolds or just gaskets? Please let me know how you guys would do this process. Thanks!
 
Hi
Just need a little help please. I know its not a very interestng tooic but i still meed some help. I've looked up other similar theeads on his topic and I couldn't find any specifications on lengths of the various bolts. Does anyone have that info? I have a local nut and bolt shop in my town and I wanted to give them the specs so they can build a kit for me. Thanks!
 
You need just the gaskets. As far as the size I guess you could try RT specialties. That's where I got the correct shoulder bolts for my 440. For a 318 I am really not sure. Maybe someone will chime in with some more info for you. good luck.
 
I ran into a problem. One of the studs that I need to use in order to hang the exhaust manifolds is stripped. When I tried to take it off using vice grips, it seems to be frozen in there. I tried spraying some wrench off in there, but it did nothing. Ay suggestions? I don't want to brake the stud off in the head otherwise I think I'll be screwed!
 
firefighter1 said:
I ran into a problem. One of the studs that I need to use in order to hang the exhaust manifolds is stripped. When I tried to take it off using vice grips, it seems to be frozen in there. I tried spraying some wrench off in there, but it did nothing. Ay suggestions? I don't want to brake the stud off in the head otherwise I think I'll be screwed!
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The two stud's on the end's of the head, are in the head with a stud w/a nut,
is because those are in the water passage's. The bolt size is 5/16x18 coarse thread, in all hole's. Just make sure you use some kind off good sealer, on the two end bolt's. Some on this site, say to use Permatex Copper RTV. As for trying to remove the stud, I would use some decent heat, but don't go overboard. I have also mig welded a nut on the stud to aid help in removing it. You may have to heat it more than once, just be careful to not destroy anything. Good luck.
 
Thanks for the tips, but I don't have access to heat or a welder. Just me myself and I. Hmmm... Is there any way to re thread a stud? I'll keep trying, but it doesn't look good right now. Is the thread pattern on the outside of the stud 5/16x24?
 
firefighter1 said:
Thanks for the tips, but I don't have access to heat or a welder. Just me myself and I. Hmmm... Is there any way to re thread a stud? I'll keep trying, but it doesn't look good right now. Is the thread pattern on the outside of the stud 5/16x24?
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a cheap propane type solder torch and some nut buster should work, but if you do break it, you can always use a heli coil repair kit ( ive used them on head exhaust holes before with no issues ).
 
Bought a torch, but didn't need it. I bolted two nuts on the stud and wrenched on the inner one against the outer one. Stud came right out. Then I hack sawed a couple of 4" 5/16x18 bolts in half to make the new studs. Thanks for the help guys! One thing down.... A hundred things to go!
 
The studs are course in the block and fine on the manifold side, but that is not a big deal. The proper end stud has a little bump in the middle so it seats in the coarse hole and you should use sealer on the head portion. They stud them as they are not in a blind hole, but wet so you dont leak when you remove the manifold (and possible because they know they will break if removed after 20 years of heat cycling and corrosion on the head end). Im about 50% successful in taking these studs out with the lock nut method as you used. I use heat and ATF/kerosene to break bolts but I still end up twisting 1/2 these right off. If you do break one in the head, all is not lost. CENTERPUNCH the briken stud (very important) and use the smallest drill you can find to drill a hole right down the center. I use a carbide bit for PC boards (HF sells them in a grab bag box for like 3 bucks, they are TINY) and then just start using larger drills in steps to enlarge that hole. Once it gets close to the tap size and very thin, you can sometimes take a punch and dislodge a side off the threads and then use some needlenose pliers and pick it out, or worst case drive it into the water jacket. IF all goes well, you should get it thin enough to start a new 5/16x18 tap (F drill .257, or a 1/4 .250) If you flub it up and the coarse doesnt grab, you can go up to the 5/16x24 size I drill @ .272 an tap.
 
To make it easy for me that is. I just purchased a complete manifold bolt kit. Came with bolts, different sizes and the washers. The kit wasn't very much and was no hassle to install. Oh this was on a 360. I don't remember who I purchased the kit from, but alot of vendors have them. I got my kit at the Chrysler at Carlisle event.
 
Very good info thanks! I have replaced the one stud already but haven't started on the others yet. What size thread is the outer portion of the original studs? I tried using a nut that was 5/16x24 and it didn't seem right.
 
ive had to weld nuts to a couple of mine, one in my big block and one in my 318 in my powerwagon. the smallblock was a bear to get to seal up, i tried pipe dope, teflon tape, rtv, shellac, threadlock, anaerobic gasket maker, no2 rtv, it all failed. i ended up using a stud extractor and some teflon goo pipe dope and reefed the stud in the hole about as hard as i wanted to go, luckily it sealed, finally. then it ate the heads (exhaust valves and seats burned up, non hardened, 73 build)....so now new heads with hardened seats, new studs and pipe goo, no more issues! if you ever have one thats seeping bad enough get it fixed asap, the coolant can leak into the exhaust ports, pool on top of the valve or in the cylinder, and ruin them. ive seen it happen before. not cool.
 
Any links or recomendations on gaskets for the manifolds? I bought some from my local auto zone but they look pretty cheap and flimsy. I don't want them to leak right after I install them.
 
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