I am starting to put my "new" engine back together. We plan to run this truck for a verrry long time. Regarding installation of stock exhaust manifolds on '02 PI heads: Which of the following do you think would be least likely to experience exhaust leaks in the future:

A) Use set of very low mileage (6K miles) studs and nuts from my '06 donor engine (free!)
B) Use the same with stainless steel flat washers under the nuts (minimal $)
C) Use grade 10.8 bolts ($$)
D) Percy's Split Lock bolts. (Only 1" long, $$$)

Keep in mind I am in dry part of California, no salt, minimal (if any) rust.
Any option will include using anti-sieze into the aluminum block.

My biggest concern with option C is the typical problem of bolts backing out over time. The only thing holding the threads into the block is the tensile forces provided by the torquing of the manifold. Studs are tightened until threads start to bind, providing superior resistance to backing out. And the nuts are self locking.

I guess I could drill the bolt heads and install safety wire, but that would be a bugger to ever have to re-do with the engine installed.

 

Found these on fleabay, just a thought.
eBay Motors: 1999-2004 ford superduty 6.8L v10 headers and y-pipe (item 280298926433 end time Jan-09-09 21:00:00 PST)=

I would go with bolts, I have little faith in the studs. You'll want to try and get the most thread engaged into the head as possible. The thread is about 1" into the head. You buy bolts from mcmaster already drilled for safety wire if you want to go that route. Stage 8 also makes a set for the V10. I used the grade 5 bolts and star washers that came with my thorley headers. I would go headers but thats up to you.

 

M8 x 1.25 x 35 stainless bolts from your local hardware store will work just fine, and most likely save you some money in the process.

 

A few comments, not that I'm an expert or anything on the subject:

The stock exhaust gaskets are just sheet metal, so no gasket crush like there is with headers. So, no reason to re-torque exhaust bolts over time. I don't think.

Stainless washers under the nuts/bolts are a MUST in my opinion, unless you use a really shiny stainless nut with a flair similar to the stock nuts. The manifold MUST be able to expand and contract, or it will either crack or break the studs/bolts.

If you use a grade 8 bolt, and it doesn't allow the manifold to move, it WILL either break the bolt or crack the manifold - or worse, hog out the hole in the aluminum head. Something has to give.

Like I said, I'd use a stainless washer no matter what.

On my headers, I used grade 8 zinc-plated (galvanized) bolts with a stainless washer.

With my '01, the stock nuts corroded themselves to the manifold. Which meant that every time the manifold expanded and contracted, the manifold dragged the stud with it. Eventually fatiguing the stud and breaking it.

I'd anti-seize everything for the heck of it too...

You say "'06 donor engine" - is it a 2-valve or 3-valve?

 

This may or may not be applicable to this installation, but years ago they used brass or bronze nuts on steel studs, and it was always easy to remove the nuts.
And the nuts also had an over sized OD, so you have lots of surface contact, what do you think?

 

As usual, great contribution. I went with the '06 studs and put the $$$ on new fuel injectors.

The donor engine was a 3V. I am using only the short block, flex plate, harmonic balancer and oil cooler. Lots of piston and valve measurements indicate it should work with 2V heads.

 

Yeah, I think we went through this a few months back. Looking up pistons for a 2006, they work for everything from '99-2007, and if you look at e-series, they are the same thing all the way back to '97.

 

You have no idea how relieved I was to read that! All the math added up, but there is still that twinge of doubt. After all this work, I would be just a tad disappointed to hear the valves and piston get into a spat...

 

Hey all,

New to the site, reading through ALL the V10 posts, but wanted to toss something out here. By the way, I have a '99 F350 crew longbed with the V10 and 4R100. I know this thread is a year old, but newer than others!

I'm about to start the old stud and manifold removal project, and put in the Ford Motorsport headers. I looked at the options for fasteners, but I think I am going to go with something I've used for years...VW/Audi studs. M8x1.25, correct length, and I can say that in NO application I have ever used them, on the street or track or rallying, have they ever failed. I also use a copper coated steel nut that is pinched so that it'll lock in place. It's a BMW part, and works like a champ. The studs are about a buck a piece, and the nuts are around fifty cents.

I'll keep a close eye on them, but I just can't figure out why they are failing in the Fords...does anyone have a theory? Cheap steel? Poor sealing of the manifolds that leaches out corrosives from the exhaust and eats the studs? I know there are a lot of those who say it's due to heat cycling in dissimilar metals, but again, I have never had a failure in a VW, Audi at high temps with mild or stainless headers on aluminum heads. So, same combo of materials, different results. I've also rarely needed to re-torque, though I do out of habit. I'll post some pics of the most recent items I used them on- a built 5 cylinder Audi head with a factory equal length stainless header- again, hard use, no failures.

Once I get it all together, in the next couple of weeks, I will post results here. It'd be nice to find an inexpensive solution to this problem.

Steve