Case Bore Diameter

[Jamie Long]

outside of SE new cylinders will be patent issue ??  best guess is yes  in some way or form  , take a stock cylinder and re work it is the next option or what ever you build must not be the same as HD

Did not need to read your mind, you made the statement about a "patent issue", i'm assuming you were referring to the Motor Company's patent on big bore drop on cylinders, maybe you were referring to a different patent and can explain further. 

The first paragraph of the drop on cylinder patent references "96 and 103" Harley-Davidson Twin Cam engines" specifically.

Either way, the M8 engines are going to get a whole lot bigger in the future

[HD/Wrench]

Well I cannot say too much but guys that are building these new larger cylinders  have told me that there some issues not talking about the drop on cylinder.  But HD took it further with what materials you can use or what they patented.  ,   With the investment for a new drop cylinder one needs to make sure you can sell it 

Will they get bigger yes they will.

[joe_lyons]

What's the spacing of the oil/coolant ports on the heads from each other on the head gasket surface.

[BVHOG]

What's the spacing of the oil/coolant ports on the heads from each other on the head gasket surface.

I have a couple sets off right now, what measurement do you need exactly?  I know that there were some re sleeved cylinders that were big enough for the head gasket inside diameter to  run into the oil hole.

[joe_lyons]

My thinking is how far can the bore go before the bore gets into the area where the port openings are at.  The gentleman working at the cometic booth was telling me that going much bigger than 4.250 is going to start getting really close to the original coolant/oil ridges that are on the head gasket they are making. 

[rbabos]

My thinking is how far can the bore go before the bore gets into the area where the port openings are at.  The gentleman working at the cometic booth was telling me that going much bigger than 4.250 is going to start getting really close to the original coolant/oil ridges that are on the head gasket they are making.

Also, at what point do the piston skirts get so short stability is an issue?
Ron

[BVHOG]

My thinking is how far can the bore go before the bore gets into the area where the port openings are at.  The gentleman working at the cometic booth was telling me that going much bigger than 4.250 is going to start getting really close to the original coolant/oil ridges that are on the head gasket they are making.

Talked with him last fall at the Drag Spec show in Madison.  From looking at the small opening it would be very easy to weld/machine if necessary. If I get a chance I will lay a gasket over for a pic.