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I removed my manifolds to adjust my valves. In the process I messed up the threaded stud on my exhaust manifold. Just a couple of questions below:

Is it possible to replace the stud on the bottom of the manifold? Machine shop maybe?

If not, is there a difference between a CJ2A and M38 exhaust manifold?

Thank you,

Dave

Hi Dave,
What does "messed up" mean?
I'm thinking you snapped the stud off and that's why you said "machine shop maybe"?

Can't go wrong spending $20 at the machine shop to take it out and $2 for a new stud.

If "messed up" means something else (like a crack in the casting?), you'll have to describe it. Photo is better.

The manifold and its parts are shown on page 24 of the September 1955 ORD9 SNL G-740.

Good luck!

Ron,

I got the nut to rotate a few threads then it locked up. Then I heated the nut up to cherry red and let it cool down a few times. After that the nut started to move. It loosened a few rotations then I think the threads just gave out because the nut just spins and does not come off. The nut is close to the end of the stud.

I was planning on trying to split the nut in half with my Dremel tool. I may be able to use the stud as is but I'm preparing for the worst.

So, the stud is still there but maybe the last half of the threads are no good. The exhaust manifold is not cracked. It's in great shape.

I did have to remove the fuel pump and take the manifolds out with the down pipe still attached. All 3 bolts attaching the down pipe to the center pipe snapped so I was worried about snapping the stud.

Dave

Hi Dave,
Even if you get the nut off and use a die to salvage the threads, I'd bet it'll give you problems again next time, even if it does tighten down properly this time.

If I didn't want to chance getting that stud out to replace it, I believe I'd let the machine shop snap it off rather than doing it myself.

Pretty sure the nut on that stud and all the other nuts are supposed to be brass lock nuts.

Have you ever had the 4 bolts out that hold the intake and exhaust manifolds together? How's your heat riser valve?
If it's going to the machine shop anyway, now might be the time for them too.

Good luck!

If I remember correctly, only place Brass locknuts are used is on the Manifold to block (7 ea). The rest of the nuts on the exhaust system are plain Brass nuts with lock washers... But only on the places where the pipes bolt together...

Got the nut off but the threads are toast. Looking for a machine shop.

I will use brass nuts next time.

I wonder how it turned out.....

I took the manifold to a machine shop recommended by someone on the G503 site. They replaced the stud for me. It was not $20. Multiply that by 10. It came out nice but I guess I could have purchased a good used manifold for less. Oh well, live and learn.

I will adjust the valves and put everything back together this weekend. This will be my first time adjusting valves. I found the section in the TM that explains how to do it.

Ouch!

If there’s any consolation a used manifold may have needed decking to match your intake. You may have avoided spending for that…

Yikes Dave.
They told you $200 up front to remove 1 stud?
I think I'd have moved on to a different shop.

I had mine planed to mate the intake and exhaust surfaces flat, heli-coiled the 4 mating bolt holes, and welded in a new heat riser flapper on the pivot shaft for less than $100.

That was my first trip to a machine shop. I asked up front how much it would be to do the job and he said depends how long it takes. I should have asked more questions. I came back to get it with $100 in hand thinking it would be less. Next time I will get a better price up front. Live and learn, a sucker is born every day and some other generic sayings. He did a good job but I won't be going back there next time.

I would be curious to know how much other shops charge. Everything is more expensive in California but I'm sure I was overcharged.

At the time I had my manifold done a couple three years ago, the shop labor rate was $67.50 an hour.

My guy said he spent 2.5 hours. That would be $168.75 at your rate.

Yeah, the time is the problem.
2.5 hours to remove one stud?
There must be something about it that I'm not seeing.

I've drilled a snapped one out myself (not on the manifold, on the block) in 45 minutes, and I'm a rookie.
Center punch the broken stud, made three passes with a slightly larger drill bit each time, pick out the last of the threads after the last pass, clean up the hole with a thread chaser.

Yes, it made me nervous. But at the time is was easier than pulling the motor and taking the whole thing to the machine shop (which I eventually did later for other more serious issues).