Head gasket

I need to replace the head gasket on my Ford 9N. I am not fond of the stud and nut method of the factory. When I take it apart, sometimes the whole stud comes out and sometimes the just a nut. It seems that the torque measurements would be off just because of the gorp that sticks in the threads of some of the studs. I am thinking of cleaning the threads with a tap and then using bolts instead. Maybe stainless ones.

Does anyone know why this is a stupid idea? Please tell me why before I do it!

Typically a stud and nut assembly will provide the same torque as a bolt, but is more resistant to loosening than a bolt due to the difference in the thread engagement between the nut and the stud, and the stud and the block.

Usually the reason the stud and nut comes out together is the exposed threads have dirt in them, or are damaged, while the threads in the block have remained unexposed and therefore clean. Basically that issue has nothing at all to do with how well the assembly will hold.

If it were mine I"d put back what was there, and call it good. Think about it, what"s there has been working just fine for, what, 40 plus years, and put back properly will probably outlive all of us.

Don't want to do that...

Several advantages to studs over bolts.

The studs get full engagement in the block threads. Last thing you want to do is pull the threads out of the block!

Most studs are fine thread on the nut end. This gives more pulling power per ft. pound than coarse thread.

Stainless covers a wide range of alloys, more for corrosion resistance than high strength. Stainless is also prone to seize and pull threads.

If the studs come out, all the better! If they're showing signs of rust and thread wear, replace them. Might want to go ahead and pull all of them and clean them up, decide weather to reuse them.

If you re use them, clean them up with a wire brush, NEVER chase the threads with a tap! You do want to chase the threads in the block with a tap.

If you replace them, be sure to use the recommended grade studs and nuts to get the proper stretch and hold. If the bolt holes in the block are wet holes (drilled into the water jacket), seal the threads with Permatex or silicone. Use oil on the nut threads. One thing you can do, if not already equipped, is put hardened flat washers under the nuts. Keeps them from digging into the iron on the head.

Hi I have had many heads off customer tractors over the years I have been fixing. I always clean and check every bolt or hole, stud or nut before I put the thing back together, some bolts have a stretch spec for length measurement also.
As I have said in posts before tractors that have been apart before can have a failure again shortly after if nothing related to the head fixing is cleaned properly, because of damaged threads or junk causing bolts to bottom and not torque the head down. Or the same with damaged threads giving a false reading.
this should be basic 101 motor rebuild class, but in some cases I guess its to much work for guys.
Ièm with the check clean everything and put it back idea. Not sure if stainless bolts will torque and react the same as the ordinary bolts, so they might cause more problems than they solve .
Regards Robert

Ford actually changed to bolts on the later flat heads.
Your choice on what you want to do there.
The studs do work just fine though.
Clean the threads in the block, put thread sealer on the block
end of the studs and screw them in just a bit past snug.
Clean off any excess sealer, then put your head gasket and head
on and torque the nuts to spec in the right order.
It sounds like you take it apart a lot. Any particular reason?
Done right, once should be good for many, many years.

GOOD post, Steve!

IMHO, tossing the studs in the dumpster and replacing them with bolts is a DOWNGRADE.

For those who doubt, ARP has made a FORTUNE offering studs to replace bolts for a wide variety of performance engine applications.

Or, those of use that just want stuff to stay tight/together!
ARP

(quoted from post at 20:03:44 08/10/14) Hi I have had many heads off customer tractors over the years I have been fixing. I always clean and check every bolt or hole, stud or nut before I put the thing back together, some bolts have a stretch spec for length measurement also.
As I have said in posts before tractors that have been apart before can have a failure again shortly after if nothing related to the head fixing is cleaned properly, because of damaged threads or junk causing bolts to bottom and not torque the head down. Or the same with damaged threads giving a false reading.
this should be basic 101 motor rebuild class, but in some cases I guess its to much work for guys.
Ièm with the check clean everything and put it back idea.[b:4b0bc97773] Not sure if stainless bolts will torque and react the same as the ordinary bolts, so they might cause more problems than they solve .[/b:4b0bc97773]
Regards Robert

Click to expand...

tainless steel bolt treads have a tendency to gall, i would not use them

Stainless would be a bad idea. Grade 5 steel bolts have a minimum yield strength of 92,000 psi. 304 and 316 stainless bolts both have a minimum yield of 65,000 psi.

There was never any thought of bolt stretch when that engine was designed or made and there were no torque specs for it as you just used the 11/16" box end wrench that came with that tractor. Stick with the studs, they only switched to bolts because the owner was needing to change gaskets everytime they did a valve job that was about every 2 years untill the valve rotator was developed and put in. And to do the valve job with studs you had to raise the hood and gas tank to get the head out, with the bolts there was just enough clearance to slide the head out but then without raising the gas tank there was just barly room if you had small hands to get in there and clean the old gasket off if it was not stuck too tightly. The bolts were just a way to cut costs in both the orignal cost and when the tractor was sent in to the dealer for the valve job. I have a 44 2N Dad bought new in May of 44 ( I came around in September of 43), and that tractor was used hard for everything on the farm from plowing to harvesting as it was his only tractor untill 57 when he bought a 38 John Deere A. And I remember him talking about those yearly valve jobs umtill it was equiped with the exaust valve rotators. I also have a 41 9N.

Clean up the studs and nuts and the holes in the block good and then use a Loctite product made for those studs !

Re-emphasize all the reasons below; NOT stainless.

Thank you Bob!

If the head and or block were aluminum I would use stainless because aluminum reacts with steel. that being said as far as I know no ford N series was made that way. Stick with the studs and nuts they hold together better for all the reason previous stated.
Ypop

That post had to be in the top three most informative posts I"ve have read on this site. thanks very much.

A lot of good information has been given to you here. Whether you choose to heed or ignore that information is up to you.
IMHO - it was built the way it is for a REASON. It WORKED. It was the technology of the day. And, it lasted for many years. The people at the manufacturer's facility were smart people. For that reason, I would ALWAYS stick with the way it was originally made.

Another point of information.....
Look at a lot of today's goods. We live in a throwaway society. Things are not made to last. The emphasis is on CHEAP. Cheap to buy, cheap to build, and cheap enough to throw away when you are done with it. What you have is a quality piece of equipment that has outlasted its original intended lifespan by orders of magnitude. Keep it original and enjoy it!