9N Exhaust Stud

[FiremanKyle]

Working on my 42 9N, 12V - and thought I had a rusted manifold, but removing the three nuts + 1 bolt I found out it was just a gasket issue. Guess since my dad did the rebuild I wasn't anticipating antifreeze
to come out (of course what else would come out, laughs), so guess it will be time to put in the thermostat finally. I am going to replace the bolt with a stud and have new nuts/washers. What install tips do
I need when I put the stud in, just torque or anything for sealant? Timing was good to find out the nut torque is 27 ft lbs, and retorqueing after a getting to operating temp.

 

[Caryc]

I guess you already know that you need brass nuts? Available here at YT.

 

[Bruce (VA)]

The nuts are brass, 7/16-20 x 5/8, NAPA part number STN104X, 27 lbs of torque. Torque from inside to outside and retorque after running to operating temp Fastenal has them for about $1.50 each; part number 75133. OEM studs are 1-5/8 long 7/16-14. NAPA doesnt stock the 5/8s length, but part number RFD 86644, 1 inch, works as does part number 86632, 2 inches. These studs are Handi-Pack items. (Ive used these longer studs on my 50 & 51 Ns, but you should make sure they do not bottom out in the block on your N as they are longer than OEM). If you dont get them at NAPA, make sure that the stud has an egg-shaped center between the different threads. Use washers under the nuts.


There are two distinctly different recommendations on tightening the studs in the block. Because the stud goes into the water jacket & is constantly undergoing extreme heat & cooling cycles, some folks like to double-nut them & tighten them down at 37 lbs of torque. Others say that its a stud & should only be finger tight w/ a good dose of thread sealer or high temp silicone on them.

Ive replaced the studs on 3 of my 4 Ns w/ no leaks; I finger tighten the studs then take a turn on them w/ vice grips.

This method of attaching the exhaust pipe to the manifold was developed for the Model A Ford in 1927. If you pay attention to what you are doing, it will not leak. You do not need tinfoil or gasket sealer to prevent leaks. Use the correct parts & install them correctly & it will not leak.



Make sure you are using the correct clamp. An automotive muffler c-clamp will not work. You need a clamp made for the N. If you have the correct clamp, it has a top & bottom. Make sure you have the clamp on correctly; check out tip # 8, below. All clamps are not created equally; the correct clamp should have 9/16 brass nuts.

Slide the tail pipe into the hanger clamp & then place the end of the exhaust pipe against the manifold. Look at it! Remember, the pipe will most always fit snugly to the OEM manifold w/o any problem, but a replacement manifold will likely not be the exact same size as the OEM manifold, so you will have some work to do. If it does not mate all the way around, put a broomstick down the pipe & into the manifold & gently bend the pipe until both surfaces mate snugly & squarely. If the exhaust pipe flange is bent, you will never get a good seal; check it out. The clamp is not a gasket; if the pipe & manifold do not mate tightly, it will leak. Do not try & hold the exhaust pipe against the manifold w/ your hand & while you tighten the clamp. Get out your floor jack & a block of wood; put the jack under the pipe to hold it tightly against the manifold. Confirm that the pipe is mated squarely to the manifold; if it is crooked, it will not seat. With the pipe jacked snugly and squarely to the manifold use your lb ball peen hammer and tap the pipe tight to the manifold flange all the way around. Its soft metal and this will only take about a minute. Tighten the clamp. (Don't get carried away w/ the jack or you will bend the pipe. Or, overtighten the clamp & snap it in two. BTDT). Put equal pressure on the clamp by tightening one side a few turns then a few turns on the other. Do not expect the clamp sides to touch; about 1/8 gap is normal.

When the clamp is tightened equally on both sides, remove the jack. If the pipe flops around, start over because you put the clamp on upside down. (Remember tip # 8)

If the block is badly pitted, (usually around # 4) you will have problems; get out the hi-temp metal epoxy. VersaChem's exhaust manifold repair, or ThermoSteel, is said to be good to 2000 degrees. Clean the area real well with brake cleaner, put a little epoxy on it, put some wax paper over it and bolt down the manifold. After it dries take off the manifold and take a die grinder and clean the epoxy that might squish into the port. Look at the manifold, again around # 4.
If its pitted & burned, it isnt going to seal. Time to surface it or get a new one. Do not double the gaskets! The gasket has two pieces, left & right (or front & back.....whatever) Use hi-temp Permatex or even Copper coat. Make sure the surface is squeaky clean!
75 Tips

 

[Tim PloughNman Daley RIP]

Better invest in the Essential Manuals if'N ya wanna be a FORD N Owner. Owner manual, 39-53 MPC, and I&T FO-4 Manual required reading. You can get the 7/16 STUDS from DORMAN or SUMMIT RACING - SEE LINK. Best to plan on replacing the manifold with new. Paper gasket usually burns off at critical point nearest #4 port (by dash end) but will burn a channel onto cast iron area too. Look close. Replacing a manifold is not a difficult task, mostly just time consuming because of all the parts that need to be removed first. You're gonna have to remove the carb and I loosen the air cleaner, definitely the tube at least, if not removing it altogether, and the exhaust pipe. Better plan on new pipe clamp as well and if pipe is in sad shape, now's the time to replace it too. You don't want to have to this job again for quite some time do you? First, drain some coolant out via radiator drain petcock on bottom or wear a raincoat. New manifolds usually come with the tree paper gaskets. Two go on the unit to block faces, one is the Carb intake flange face. You DO NOT USE any Permatex or other crap. The STUDS as well do not need and sealant. Apply a dab of clean engine oil at assembly. You do know STUDS are a nominal size (7/16 in this case) but use both a coarse end and fien end on thread size. Engineering Fact: The Coarse Thread size (NC) always goes into the cast iron mating part. The Hex Nut size, Fine (NF) always goes out towards you. 7/16-14 UNC; 7/16-20 (UNF). Fasten with brass hex nuts and steel lock washers as Bruce (VA) said and torque set at 27 ft/lbs if you insist on setting a torque value. Me? I just use my built-in torque meter (arms and hands).



Tim Daley (MI)
7/16 STUDS FOR MANIFOLD

 

[FiremanKyle]

Found the N manifold stud on Amazon, they shipped it I got it the next day. Assembled it back together, reused the manifold, however there was some pitting near the #4 cylinder I overlooked, removed the manifold it wrecked the newer gasket as it was still warm. Got a new manifold gasket from Steiner on a drive by and assembled with the new manifold I had purchased, and runs a lot quieter. Retorqued the nuts after it got to operating temp, so should be all set for the next issue.

Thanks all for your help!