VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 '38 Exhaust/Intake Manifold Spacer?

Hey all,
I have a bit of a conundrum here. My intake manifold doesn't want to line up properly to the head. The exhaust fits perfectly, but the intake seems about 1/2" to low. Is there a spacer or something I am missing? Here are some pictures to help visualize the problem: Manifold

Thanks,
Davis

Where did this set come from? Was it previously on the car, or is it new to this engine?

If they are replacements, are you sure that they are the correct ones? Are the casting numbers correct?

By the way -- Great Photos!!!

-Bill

are you missing the alignment rings that go inside the intake & head ? frank

Bill, this set came with the car the part numbers match what would have been on originally.

Frank, there are no alignment rings in currently.

Thanks,
Davis

Davis,

We discussed last 3/27/2013 the importance of NOT mating the intake manifold to the exhaust manifold until you have mated both of them to the head of the engine. Just start the 4 bolts holding the intake to the exhaust manifold together. Tightened them sequentially after all the manifold bolts are tight to the head. Thankfully, you didn't try to force anything. It is easy to break off the areas where manifolds are attached to the head. When all the areas are seated you can torque all the bolts tight. I think it is around 40 pounds of torque? Remember, to check the tightness after about 500 miles with the engine warmed up.

Maybe, someone else could comment on how often to recheck the torque on a new rebuilt engine head and its manifolds?

Good luck, Mike

P.S. The alignment rings will not cause your seating problem unless they are not fully compressed into the head. I usually start them into the head by hand then tap them in lightly with a brass hammer.

To get more info checkout our Chat index of posts by doing an Advance Search. Use the Keyword Search Term "manifold" The Date Range "newer than 1 year" and "older than 1 month."

Following, are the two posts I posted in April/May of 2013 on this topic.

If the two manifolds were separated then re-mated together it is easy for them to be out of alignment, and thus not aligning flat to the head causing leaks. The best practice is to tighten the two manifolds to the head then two each other. If you can not get them to mate then loosen everything up. Start the mating bolts but leave them loose then gradually tighten the bolts to the manifold. You should try to tighten the bolts all a little at a time so they seed the same. Do the mating bolts between the two manifolds a couple of steps behind the others until they are close to tightness. I would also take a child's toothbrush and put a little anti-seeze on each bolt as a lubricant. By little I mean just barely coating all of the threads. Remember you are dealing with cast iron so it would be easy to brake something with too much muscle. I would assume the torque settings could be in the 30 pound range with re-torquing being necessary after driving the car and it being well heated up. My advice comes from working on 216 engines of the 40's. They also have steel ring inserts that seat between the head and manifolds in each of the intake and exhaust ports to help with the sealing leaks, besides the heavy duty gaskets. I think the bolts should be checked for tightness on some regular maintenance schedule. Maybe once every 2-3 years. Some might assume the anti-seeze is causing the problem, but I like being able to remove and tighten the bolts easily.

In most cases the manifolds mated well before they were removed to be painted or the engine repaired so with a little patience they should reattach without a problem. A lot of us have had the same experience as you, so should not be blaming the gasket or even the need for re-milling. Good luck, Mike

Second Post

A couple of days ago I reinstalled my manifolds on my rebuilt motor. I did it first without the gaskets to see how out of plane the two were. I could easily slide a piece of paper under all but one of the exhaust ports. So after loosening the manifold head bolts I loosened up the fastners holding the two manifolds together so they could easily move. I then retightened both manifolds to the head and found I could barely slide a piece of paper under any of them. One was so tight I could not. I retightened the fastners holding the manifolds together and then loosened and retightened the manifolds with their gaskets and metal intake ring seals, and said "that was good enough." Thanks, Mike

P.S. I forgot to hit the "that was easy button."

I am about to go postal here.... I have taken it off and put it back on several times now. Mated them both separately and everything I can think of nothing works. As soon as I tighten down the four bolts the intake gets pulled down past the ports in the head. The exhaust does not move, but no matter what, the intake gets pulled down too far. Anyone have any idea what is going on here?

Thanks,
Davis

P.S.
Mike, what I am getting from your post is about getting it to mate flat against the head. I don't have a problem with that. My problem is that the intake (when everything is tight) gets pulled down about 3/8" too far past the intake port resulting in a gap past the head that allows too much air into the mixture. Please feel free to correct me if I am getting the wrong info from your article

Do you have the "box" gasket between the two manifolds?

Yes, there is a gasket that would act like a spacer, item 3.272.



It looks like someone machined the mating surfaces of the two manifolds, which will increase the gap. There should be rings, see the drawing items 3.281, which align the intake manifold. Remove the studs on the intake and mount the two manifolds then measure the gap, all the way around. Buy some high temp gasket material and cut it to fit. You need to find the rings or fab up a substitute to fit the intake manifold to the cylinder head correctly, otherwise you are just eyeballing the fitup and the gasket thickness.

Hope that helps.

Brian

That's why I asked the question Brian. It's starting to sound like the gasket is missing or, as you note, something has changed dimensionally to change the spacing.

If the intake manifold aligning sleeves are missing you can get a set from the Filling Station www.fillingstation.com. If with both the intake and exhaust manifolds mated to the head there is a 3/8 space between the two manifolds I would look for replacements. I could see a 1/8th space if you are missing the gasket but anything else means the manifolds must have been machined or they are not a matching set for your engine year.

Good luck, Mike
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Do you have the exhaust pipe connected to the exhaust manifold?

I measured the gap today. It turns out that the gap is 3/10", .076", or 1.930mm. This seems too large for a gasket to fix. I cannot pull the intake any further up because the exhaust catches on the studs. Any thoughts?

Thanks,
Davis

Double up your gasket???

Have you layed the intake and exhaust manifold on a flat surface and layed a straight edge on hard surface? You could draw a straight line and then put intake on it and then exhaust and once lined up straight clamp them down. Then you could slowly tighten the 4 bolts that hold them together. Go slow and see what happens.
Just an idea I would try.

I don't know how thick these gaskets are so you may have to buy a couple. If you can find a thick high temperature very ridged gasket material at an auto parts store I would use that. My concern would be that if you bolt the manifolds together without the gasket, are all the surfaces that mate to the cylinder head flat? in other words, when the surfaces were machined, were they machined equally all the way around?

The next issue is those surfaces, where the new gasket goes, are probably not grooved to help hold the gasket in place. the thicker the gasket is the weaker that joint is, hence the need for a ridged gasket. The one in the picture may be but it's hard to determine from a photo. Stacking gaskets makes for a weaker joint, hence the search for a one piece thick gasket.

Brian

I would not try to draw the two manifolds together as cast iron is brittle and can easily be cracked/broken when under stress.

Has the car ran with the intake and exhaust manifold you are working with?

So, I have put on two gaskets, will need a third, but it seems to work alright. However, a new problem has arisen. Now when I am breaking or let my foot off the gas when slowing down the car will die unless I give it gas. If I am completely stopped and idling the car won't die, but as soon as I try to slow down or stop it wants to die. Fuel pump, carb, fuel line getting too hot? Anyone experience something like this?

Thanks,
Davis

cracked intake or leaking around the intake/head. maybe?

Sounds like a vacuum leak. Use a propane torch turned on to locate the leak. The engine will speed up when it sucks the propane into the engine.

Wow..that's a new one for me. I've never heard that before. Sounds like it would work,great post.

I havent tried the propane torch but the aerosol carb cleaner works well for that purpose as well.
Tony

The nice thing about using the propane is that its a gas, the aerosol carb spray works fine also but goes on wet and can make a mess and it is also hard on some paints.

Well, I cannot seem to find it I have been all over the engine bay with propane, carb cleaner, and a tissue. No such luck. Are there any places that the average person may not think to look?

Thanks,
Davis