VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 1940 216 Manifold Bolt Suggestions Needed

I am trying to remove my intake and exhaust manifolds to replace the original gaskets. Surprisingly, a daily dose of penetrating oil made extremely easy work of all bolts for both manifolds. Except there always has to be ONE right!

The problem is that one of the bolts sits so closely to manifold runners that I can’t get a socket on it, nor can I get enough of an open end wrench on it to get enough pressure on it to loosen it.

I am at a loss and have no idea how in the world I am going to get this out let alone get a new one in. Help?!

Which one? I think a thin box end will fit all on my 38 if I remember right. If you can let me know which specific bolt I can go look. I believe the engines are the same 37-40.

I’ve attached a photo of the specific one. Yellow arrow points to the bolt, red line shows the gap that is killing me.

I can get an open end wrench on it, but the boss for the intake on the right side is in the way to get enough of the wrench on it to torque it loose without rounding it.

I thought about using a cutting wheel and cutting the distribution spacer or whatever it is called. That would release the flanges of the exhaust manifold which may help?

Otherwise, I grind some thickness off an extra 5/8 wrench and try that.

I'll try to remember to go out to the garage tomorrow and look at mine.

I don't remember having that problem on any 6 cylinder Chevy. Isn't that a 9/16 bolt head? If it is a 5/8, that could be the problem.

Mike

I went out an took a peek. It's tight for sure but not quite as tight as yours appears to be. I couldn't get my box end on it but I think using a socket on a swivel might work. Sockets are usually thinner wall than wrenches. Try that with an extension to get the ratchet out far enough to clear might be the trick. You're starting to round over the bolt so be very careful with the open end wrench. Another option might be a 5/8" wobble socket or thin wall box end wrench. I know Snap-On makes them. Other's probably do as well.

Those bolts are supposed to be 5/16 with 9/16 head. If you have a 5/8 head someone has up-sized the bolt and that is your problem. You are going to have to grind a box end down or cut the bolt.

Can you get visegripes on the exposed threaded portion of the bolt?

To echo what others have said yes it is 9/16 and I was able to get a thin box on it. The normal open end would only turn it about a flat at a time the thin open end did a little better. If you have 5/8 it wouldn't hurt to make your wrench smaller or try the other suggestions.

I don't remember any problems and I recently replaced the gasket. It is a 39 216.

Dave

As usual these guys are right. I went back out to the garage and looked again. A 9/16" box end slipped right on. Doh.

Tiny - Thank you for the suggestions! I couldn't get a socket to work no matter how hard I tried because the space was too tight.


Mike - I had lots of tools out and it never occurred to me that the size wrench needed was different for this bolt than the others until you and Tiny mentioned it! I checked the others and they were all correct. That explains why only this one is giving me an issue!

Bill - There isn't enough room to get a pair of ViseGrips on the threaded part. I suppose a small pair maybe, but I don't think they would hold up to trying to turn it.

Thank you to everyone! WIth your help, I at least solved the mystery of "why" it is a problem! I'll make sure the replacement bolts will be as designed!

My plan of attack today is:
1) Grind down a wrench (maybe try both open and box end?) to fit in the gap.

2) If that doesn't work, I am going cut the "keeper" between the bolt and the exhaust manifold. If I can get that out of the way then the manifolds should come off with the bolt still in, allowing me to take the bolt out without any issues.

Thank you again everyone! I can't thank you enough and hope I can return the favor!

Phil

I would cut through the threads as far from the head as you can.

One other item caught my eye. It looks like there are multiple gaskets under the exhaust flange but only a single gasket under the intake runner. That increased thickness has angled the retainer and forced the bolt head closer to the manifold.

Phil,
Try using a punch to rotate the clamp.

Mike

If you can cut the lock washer loose (cut-off tool or dremel) it might give a little extra room. I would not be too concerned about cutting the clamp as they are not hard to come by. Once off you could get a flare wrench on the bolt.

Thanks for the suggestion of using a punch to re-orient the hold down. I tried that but the seats in the manifolds won’t allow that.

Update!

Was able to get the bolt out by modifying the wrench. Once I got both manifold off, I broke a bolt holding the intake manifold to the exhaust manifold. But, the bright side is that I was able to get the two broken studs out of the far ends of the exhaust manifold very easy using ViseGrips. So, I call it a draw.

Spent the rest of the night cleaning 83 year old gunk off the bottom of the block. I was very surprised to see so much much crud and old oil gathered under the manifolds and all down the front crossmember!

Now I am faced with the dilemma to paint or not to paint? I want to, but also don’t want to go too far. I did take the generator apart and prep/paint that and its bracket. I researched a little and found the most common photos of these to be black body with the aluminum (I assume) ends natural color. So, that’s what I did.

I think I need to start a thread in the appropriate forum documenting this winter’s planned projects. Not only might someone enjoy or benefit from it, it will also keep me on track.

Thanks for your help everyone! Worked like a charm!

Hi Rusty. I didn’t run into multiple gaskets under either manifold, but did run into the gasket having rusted and delaminated pretty badly. Could that explain what you are seeing?

I am going to take the manifolds to a friend and have them media blasted today. Hopefully that will help to get the very old gasket material out. Once blasted, I am going to take them to my local machine shop and have them plane both manifolds to get a level edge again.

That explains what I see. Thank you!

One item to check is the size and pitch of the threaded hole in the head for that bolt. It could be that the 3/8-16 hole got stripped. Someone drilled and tapped it to the next size, 7/16-14. That bolt would have a 5/8" hex head.

I agree with checking if they need planed. On my 216 I did a trail fit of the manifolds against the head without a gasket. I had the 4 bolts that hold the 2 parts together installed with that gasket in place but loose enough so things could move. I was not able to slide a .003' feeler gauge around any of the ports. So I did not plane mine.

When I did the final installation the last bolts that I tightened were the 4 that hold the 2 pieces together. Everything sealed great.

I did repaint the intake manifold with the Chevrolet gray engine paint. It held up well and did not peel or discolor. I did use a higher temp engine primer.

I did not bother to paint the exhaust manifold. If you search this forum and others you will find a full rage of ideas and opinions about what treatments work and do not work for exhaust manifolds. My thinking was that the original engine paint burned off quickly so that is the way it looked after a few weeks of use.