How To "Exactly" Install Exhaust Manifold Studs?

soundhd · Oct 18, 2017

Have to replace my exhaust manifold gaskets. Found out the holes go into the water jackets, currently have bolts instead of studs so bought a stud kit. Have also found out have to use a sealant when installing the studs but have another installation question.
1. The "kit" came with 4 extra long "nuts". Three are very long and one is a bit shorter. Which locations are they used in?
2. No washers come with the "kit" so no washers are needed?
3. Have never installed studs before, know to run a thread tap through each location first but how do you exactly install a stud?
4.Think maybe you put one of the nuts on each and use them with a socket when tightening the studs but thought I would ask first?
5. Is there a torgue setting for the studs themselves?
6. How long after the installation of the studs should I wait before I install the manifolds or can I install them right away?
7. How long before I can start the engine after the installation? Assume there is a drying period for the stud sealant (using Loc Tite Gasket Sellac)?

Sorry for all the questions, just want to do the job right the first time.

thanks ( a stud "newbie")

miller · Oct 18, 2017

soundhd said:
3. Have never installed studs before, know to run a thread tap through each location first but how do you exactly install a stud?

Just make sure your not cutting new threads. Just want them clean.
'Test fit' each stud into each hole. Should start, go in about halfway, start to tighten. If they go all the way in, check for thread looseness. If their too loose, the threaded holes are over-size, and need to be fixed.

Easiest way to install the studs, is double-nuts on the fine thread end. Simply tighten one nut against the other, and use the top nut to run the stud in.

Sealant...paint the threads going into the head...and the end of the stud. The coat of sealant on the end will hold down that end rusting.

747mopar · Oct 18, 2017

^^^^ Agree. I've used High temp RTV with no issues for sealant.

Billccm · Oct 18, 2017

I'm watching. I assume this is the fastener kit you bought?

http://www.manciniracing.com/mabenexmafak1.html

Yatzee · Oct 18, 2017

Fully inserted a stud will stop going in when it reaches it's collar. Indian Head sealant is the best thing to use. Permatex makes it under a different name, it comes in a small plastic container with a brush inside the cap and is dark brown in color. Torque studs evenly 20 to 25 ft. lbs. Torque nuts (fine thread) 15 to 20 ft. lbs. Check your gasket manufacturers specs to be sure. If you have leaks after installing your gaskets are junk or the flange for the manifold needs to be trued. Some say not to use a gasket at all but the gasket creates a thermal break between the manifold and the head as well as sealing slightly uneven surfaces.

MoparLeo · Oct 19, 2017

The main purpose of a gasket is to compensate for different expansion, contraction rates of dissimilar materials like aluminum and cast iron. Many auto makers for years did not use an exhaust manifold gasket as the manifold and cylinder head were made of very similar materials and did not need a gasket. The sealant is not intended to completely harden on the studs. Only the outer studs go into the coolant jacket.

http://www.mymopar.com/torquespecs.htm

soundhd · Oct 22, 2017

Billccm said:
I'm watching. I assume this is the fastener kit you bought?

http://www.manciniracing.com/mabenexmafak1.html

No I purchased part #HF-8065C 1968-71 383/440 HP C-Body Exhaust... http://www.manciniracing.com/mabenexmafak2.html
thought maybe I ordered the wrong on one but when I started the removal process I did have studs in place and when I removed the nuts I did have 3 of the longer nuts and one of the shorter nuts so I guess this kit will work for me (a couple of the studs came out the the nuts). Still learning Mopars.........

Billccm · Oct 22, 2017

Interesting. One says c body only, and the other says a body only. Does mancini have a b body exhaust manifold set?

soundhd · Oct 23, 2017

Billccm said:
Interesting. One says c body only, and the other says a body only. Does mancini have a b body exhaust manifold set?

I guess you will have to call them.....I'm a Mopar "newbie" and still trying to figure all this Mopar "stuph" out..... I always thought a 383 was a 383 and all the parts interchanged including exhaust manifolds...same with the 440 engines. Looking at the different exhaust manifold hardware kits list on the Mancini web site something must be different with the manifolds but not really sure what.

Billccm · Oct 23, 2017

This looks like the correct kit for my Road Runner; I will call Mancini this week to confirm.

http://www.manciniracing.com/mabenexmafak.html

Keep us updated on your job!

ragtp66 · Oct 25, 2017

For the studs going into the heads use arp thread sealer which is definitely not the same as RTV
If you want a good seal at the heads use the copper gasket maker LIGHTLY to the manifold and just draw the manifold to the head do not crank down on the nuts just snug let them sit overnight to cure and then torque to final spec I don’t have the figure handy but around 11-13 ft lbs comes to mind but double check that.

As far as which bolt kit to use get the casting numbers off the manifolds and order the correct kit for the manifolds your using not the car or the engine order them to match the manifold application then they will be obvious where the long tube nuts go.

Auggie56 · Oct 25, 2017

Depending which manifold you use you will need a number of these washers. Used only where its a standard nut to manifold.

https://www.classicindustries.com/product/mp700217.html

rakort · Oct 25, 2017

Auggie56 said:
Depending which manifold you use you will need a number of these washers. Used only where its a standard nut to manifold.

https://www.classicindustries.com/product/mp700217.html

Interesting this says for small block. Aren't we talking about a big block here? Or does it apply to both?

Auggie56 · Oct 25, 2017

rakort said:
Interesting this says for small block. Aren't we talking about a big block here? Or does it apply to both?

I just ordered some. They should fit as the studs are the same size. I'll check them on the fit when they get here and let you know. These just came out this spring, I'm surprised they dont list them for the big blocks. Worked at a dealer in the seventies, don't think I lost my memory just yet.

rp69 · Oct 31, 2017

Hello, newly joined. Do not use a manifold gskt. Its the reason you have a leak. Take manifolds to a machine shop and have them machined flat. You can install dry, or put a small amount of muffler cement around each port. I usually go dry. Proper torque from center of manifold to outer ends is important. Small blocks used 5/16 studs, big blocks are 3/8s. Both are fine thread. Thanks.

69bfan · Nov 1, 2017

The conical washers were only used on small block and Hemi applications. Not used on the big block applications. The tubular style nuts, long or short, is based on the manifold type. Each application is different in the combination of long vs. short needed for each set of exhaust manifolds. These kits are sourced to most of the vendors from AMK and nobody to my knowledge has yet to provide a correct big block A-Body kit. Would be simple enough to do, just swap out a long for a short that I recall.

68Charger440HP · Nov 29, 2017

It might be a little late but just in case you didn't want to use the double nut technique to install the studs, Snap-On makes a special socket set that installs studs very easily.

How To "Exactly" Install Exhaust Manifold Studs?

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