The Stovebolt Site Forums The Shop Area Engine Shop Intake Manufold to Exhaust Manufold Bolts

Hi List,

I will be home soon (for good) and can start making some progress on my 55 first series. I have a new (to me) exhaust manifold to install and I was wondering if the bolts that attach it to the intake are anything special- in case I break one taking it apart.

Thanks,

Joe

Other than being a specific length, I believe they're just plain old Grade 5 bolts. Snug both manifolds onto the cylinder head before tightening the bolts all the way, allowing the best alignment between both manifolds and the surface of the head. Lots of KROIL and some heat helps to get them loose without breaking anything.
Jerry

Don't forget the intake rings. They're harder to find than the bolts.

Be a good idea to chase the threads too, try to find a proper chase or and old tap. If you use a brand new tap it'll try to cut threads, you don't want to do that. An old tap is worn down a few thou and it'll clean the existing threads right up.

I had to drill and tap a couple on my '46 and they weren't bad. With luck, the heat and torque of the drill will spin the stub out of the hole. Definitely use plenty of penetrating oil and care to take it apart and clean the threads well before reassembly.

Joe,
If you are worried about breaking the manifold bolts when trying to remove them from the engine, try this and try not to call BS about it. Try to carefully tighten the bolts! You should get some movement. Then back them out. I don't understand the physics behind why this works, but I have been able to get this to work on nearly all of them which I have tried, even Furds (notorious for breaking)
Carl.

Thanks Guys,

I can get the manifolds off the engine, no problem. It looks like the intake and exhaust manifolds fasten together with 4 bolts - two long and two short. I will work slowly like Jerry suggested with Kroil and a propane torch (its all I have)

joe

Two studs inboard, who's exposed shank 9 times out of 10 will be
so eaten away by rust from heat and moisture that they will
snap off.
And two bolts outboard, which if soaked over night usually
can be persuaded to back out.

If you're pitching the exhaust manifold then no sweat. But if
you're intention is to save it, then you are in for the fun of
tying to drill out the old stud stump. Got to be on center or
you will damage the original threads. Here is an example of one
that someone tried to drill by hand and got the hole off center
and wallerd out:
http://www.pbase.com/dennygraham/image/136491216
This required a fixture and the addition of a Helicoil to
straighten it out:
http://www.pbase.com/dennygraham/image/136491494
Lots of work but it corrected a poorly done repair and made a
usable manifold out of a cadaver:
http://www.pbase.com/dennygraham/image/136491556

Denny Graham
Sandwich, IL

Thanks Denny! So the two inboard bolts are actually studs...in the likely event that I break them does anyone know who carries them?

Joe

On a stubborn bolt I'll heat it and take a stick of bees' wax to it. The wax gets drawn in and makes things a little easier.
I find the bees wax at hardware stores, lots of times they'll have a small bucket of sticks near the cash register. My local hardware asked what I used them for, after I explained the bucket was sold out in a few days!

A muffler and exhaust business or FLAPS will likely have replacement studs with brass nuts readily available.

Another source for almost pure beeswax is the wax ring hardware stores sell for sealing a toilet to the floor. I also use that wax for the home-brewed bullet lube I make for my reloading. Beeswax, chassis grease and paraffin as a stiffener- - - -I lube and shoot a couple of thousand cast bullets that way every year. The bowl rings are a LOT cheaper than buying beeswax in more conventional form!
Jerry

No not the exhaust studs that hold the exhaust pipe to the exhaust manifold, those are easy to find. I need the studs that fasten the exhaust manifold to the intake manifold (235 straight six)

Thanks

I just measured the studs in two manifolds stashed away in my storage building. The 216 manifold has 3/8 X 2 1/2" studs, and the 235 studs are 3/8" by 3" long. The thread going into the manifold will be UNC- - -3/8-16. The end with the nut on it can be either 16 or 24 thread- - - -just use the corresponding nut. A lot of standard-type studs available at a FLAPS will have a STD thread on one end, and a fine thread on the other.

Chevy small block V8 exhaust pipe studs used with a heat riser valve will be almost the exact length you need for the stovebolt manifolds, and a set of brass nuts for them and some anti-sieze compound will keep the threads from rusting together again. Just take your time getting them out!
Jerry

Greetings from New Jersey,

Modern Chevrolet Company
Winston - Salem, N.C.
parts dept.
phone: 866-391-5629

They have ( 2 ) Studs
GM # 3.275
GM # 3836709

The original part # that appears
in the 1954 parts manual is:
GM # 3.275
GM # 3835576

GM # 3835576
was superseded on
1 - 1 - 1956

This is a tough part to find.

PICS@photobucket

http://i669.photobucket.com/albums/...ntake_Exhaust_Studs_PIC__zpsdad6943b.jpg

I bought these on ebay a year ago.
I've only seen them on ebay this one time.

You can email Bruce Bugay in Virginia
to see if he has any.
[email protected]

http://i669.photobucket.com/albums/vv57/glp0329/GMManifoldStuds2NOS_zps932a6065.jpg

George
in
New Jersey

Or if you have a buddy with a lathe, you can spin you up a set
for next to nothing. Here's a batch I made up from 3/8" SS and
made the brass nuts from some 9/16" brass hex stock, both of
which I dug out of the scrap bin. Cheaper than running round
the country burning up petrol looking for the right fasteners.
http://www.pbase.com/dennygraham/image/136491783

DG

I'd rather have DG's stainless steel
manifold studs.
Beautiful work !
Very impressive to say the least.

George
in
New Jersey

I bought stainless-steel studs of different lengths and different threads on each end from Totally Stainless. I have no lathe, and no friends with a lathe closer than in VA, so these studs cost next to nothing in comparison to getting a lathe (and becoming adept in using it).

You mean after all these years they won't give you the key to
the machine shop after school lets out??
Lathe is simple, turn switch on, crank handle, that's all there
is to it Tim.
Then you get the personal satisfaction of saying you did it
your self.

DG

Thanks George! Bruce does not have anymore but your dimensions helped me find something that should work, Dorman part number 29153

Joe