Here's a question that I thought that I knew the answer to, but didn't ![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
How is the cylinder pressure held in the cylinder? In other words, what seals the cylinder head to the cylinder?
I know of course that the head is screwed to the cylinder barrel, but what forms the seal?
1. Is the top of the barrel, what would be the head gasket surface on an automotive engine, screwed hard against a matching 'deck surface' machined in the head?
No, that's not it. That is what I always kind of assumed was happening but after examining several cylinders, and a few Google Images, you can see that the barrel definitely does not seal that way.
2. Do the threads themselves, possibly with some kind of sealer, provide the seal?
3. Does the outer part of the head screw down and form a seal against the top barrel fin?
4. On the outside of the barrel, above the threads, the cylinder is smooth for maybe a half of an inch from the top of the cylinder to the top of the threads. Does this area perhaps form an interference fit in the AL head and so provide the needed seal?
5. Something I've missed completely?
Number 4 is getting my vote as of now, but I'm ready to wrong again!
Randy
How is the cylinder pressure held in the cylinder? In other words, what seals the cylinder head to the cylinder?
I know of course that the head is screwed to the cylinder barrel, but what forms the seal?
1. Is the top of the barrel, what would be the head gasket surface on an automotive engine, screwed hard against a matching 'deck surface' machined in the head?
No, that's not it. That is what I always kind of assumed was happening but after examining several cylinders, and a few Google Images, you can see that the barrel definitely does not seal that way.
2. Do the threads themselves, possibly with some kind of sealer, provide the seal?
3. Does the outer part of the head screw down and form a seal against the top barrel fin?
4. On the outside of the barrel, above the threads, the cylinder is smooth for maybe a half of an inch from the top of the cylinder to the top of the threads. Does this area perhaps form an interference fit in the AL head and so provide the needed seal?
5. Something I've missed completely?
Number 4 is getting my vote as of now, but I'm ready to wrong again!
Randy