Request Advice Installing New D17 Manifold

I had replaced the manifold on my D17 IV probably 5-6 years ago.  At the time, the old one was severely rusted and unusable, so I bought a new one, American made it said.  I was careful installing it, with clean surfaces, and I used some copper coat on the gaskets.  Anyways, it started leaking on the two center exhaust ports last year, and I finally got around to putting it in the shop.  When I pulled the manifold, the two center round ports were in very rough shape on the manifold, and not the greatest on the head itself.  It is almost as though the metal gaskets just welded themselves to the manifold, and somewhat to the head.  I gave up trying to clean up the manifold ports, and ordered another one. I figured a machine shop would cost more than the ~ $200 for a new one, plus I need the tractor back in service and don't have a local shop to work with.  The ports on the head I think I have pretty well cleaned up using a wire brush and fine sandpaper, but they are still a little pitted.  I think with more work they will smooth out. 

I know I ran it longer than I should have with the two center exhaust gaskets leaking.  I'm just wondering how best to prevent this again on the new manifold.  Are gaskets today just junk, and don't hold up?  I had used copper coat, just because it seemed like a good idea, but perhaps they hold up better just dry?  The intake and the outer two ports are all in perfect shape.  It is the center two round ones giving me trouble.  I never checked the last manifold for flatness, but short of sending it out to a machine shop, I can only check it with a decent straight edge for obvious warping, which I will do when it arrives.  

Anyone with advice on how to get this new manifold to last more than a few years?

 head and then alternate with the other four nuts while working up to whatever the proper torque is. Gaskets need to be DRY !! Clean off the side of the cylinder head pits clean and smear some high temp gold color RTV on those pits and then assemble the manifold so the metal gasket holders seal against this RTV. Again, gaskets dry and multiple retorqued many times when COLD.  *** The torque spec of 35 - 40 ft lbs is for a healthy manifold. Be cautious if the manifold is badly pitted or thin on the ends as you might break off an ear.

The new manifold will be in tomorrow, and I've been cleaning things up, using various grades of Scotchbrite type pads on a drill.  I'm not done yet, but here is a picture of the ports.  It is cleaning up better than I thought.  Some of what I thought were pits were leftover gasket welded to the head.  There are some pits though.  I have little faith in the gaskets that will come with the manifold, if they are some unbranded Chinese junk.  But there isn't a lot of choice on the gasket set, and even if I got one from NAPA they probably all come from overseas.  

Anyways, I'm planning to follow Doc's advice and "go dry", unless everyone thinks the pitting is too deep.  The intake ports are in great shape, and polished up nicely.  

Opinions?

Of course, installing the new manifold was going way too easily.  I had installed new studs with the previous manifold, so they are only a few years old.  I had installed them with Permatex 2.  The old manifold said made in USA.  The new one is made in Taiwan.  It is about a 1/2" thicker than the old one, and the old studs are just a bit too short, so I have to install the new studs I ordered with the new manifold. Well, of course 3 came out easy, 2 were difficult but yielded once I explained to them that they had to move.  The last one is no go.  With major vice grip force and heating with MAP gas cycles, and penetrating oil over a few days, I have gotten this one to move a bit.  I can get an 1/8 of a turn on it back and forth, but that's it.  I'm limited with the leverage I have with the vice grips, and they slip and just eat up the stud.  The force needed is well beyond double nutting or anything.  So close, but so far! 

I have no intention of damaging the head or having the stud snap off flush.  I've been cautious so far in applying heat.  However, I am starting to consider cutting the stud off about 3" out, and welding a nut to it.  Of course, there is no guarantee the stud still won't snap off, but at least I would have some control over moving it back and forth a little, and along with oil, perhaps I can coax it that way.   Another option might be to cut the stud, and weld a new one of the correct length to the stud.  I would have to position the weld so it is in the free space between the head and back of the manifold before it enters the hole.  If I'm super careful with the welding, I'm assuming that much heat won't damage the head or the head gasket?  I'm being a little overly cautious.  I just wish the little critter would back out, then I could finish the project. 

Any ideas or suggestions on how to get this stud out are welcomed. 

What a pain the neck this project has been.  I planned it would be a few hours to pull the old manifold and put the new one on with fresh gaskets.  Anyways, I welded a nut onto the end of the offending stud.  I used a 1/2" impact wrench with 100 lbs of air.  Back and forth, no movement, until finally the stud snapped in the middle.  I decided not to chance welding another nut on and having it snap off flush, which I figured would really ruin my day.  I cut the stud at the end of the threads coming out of the head, and used a 7/16" coupling nut, along with a lock nut.  I cut and threaded one of the new studs for the correct length.  Overall, I lucked out that there was enough of the old stud to work from.  Odd, that I had replaced all six studs only a few years ago, and all had Permatex on them to prevent leakage.  I have no idea why this one decided to fasten itself to the head like that. 

I am following Doc's advice and installing the gaskets dry.  They came into the world dry, and dry they will go out when their time comes.  I think the port surfaces cleaned up nicely and should seal.  

I bought the manifold from DJ's, but it looks like many vendors are selling the same unit.  It is Taiwanese.  I have a question though.  The metal gasket set has two fiber gaskets each.  I am not sure why there would be double gaskets.  I have everything ready to button up, but decided to wait until I find out if I should use the double gaskets, or just single?  I have it in place with just a single fiber gasket, but I will check around as to why they supplied two.  

Another odd thing about this manifold is the vacuum port on the left side.  I thought it would be some kind of pipe thread.  However, it turned out to be a regular 3/8" fine thread.  The threads were rough, and I had to chase them several times and then plugged it with a regular short bolt with some sealant.   

Anyway, almost there.  I'll torque it up once I'm sure of the gaskets to use.  So much for a 2 hour afternoon job.