OHV engines vs. L head engines


#1

Can someone explain what a L Head engine is,and how it differs from a OHV engine?


#2

On an L-head engine the inteke and exhaust valves are located in the engine block instead of the cylinder head. On motorcycles the valves are located in the cylinder itself instead of the cylinder head.
On the OHV engines the valves are in the cylinder head and hanging over the cylinder bore instead of being located beside it.

L-heads are also called sidevalves, flatheads, or even Ricardo heads after the guy who designed it originally.
The L-head design does not flow as well as the OHV designs but are able to put out some very good low end torque and they’re much, much simpler to work on.

Hope that explains it.


#3

Perfectly. Thank you


#4

Jeep once made a 4 cyl engine with the exhaust valves in the block and the intake valves in the head…I think they called THAT an “L” head…


#5

After reading the posts, I think that having one or both valves in the block will form an L shaped combustion chamber if you count the cylinder as part of the combustion chamber, as you should. The other difference is that the intake manifolds look strange because there are intake passages in the block.


#6

Wasn’t that arrangement known as an “F” head?


#7

Cam in block, two valves in the block, same side of block = “L” head
Cam in block, two valves in the block, opposite side of block = “T” head
Cam in block, one valve in the block, one in the head = “F” head
Cam in block, two valves in the head = “I” head, AKA OHV
Cam or cams in head, two or more valves in the head = OHC

See http://en.wikipedia.org/wiki/Cam-in-block