What does "OHC" mean?

In the last two blog posts we discussed OHV and the advantages of OHV.  Today we will discuss OHC, what OHC means, and what OHC can do for you.

Some of today's lawn mower engine manufacturers are coming out with OHC engines.  There are an increasing number of OHC engines hitting the power equipment market.  This is not all good and it definitely is not all bad.

What does OHC mean?
OHC simply means that the camshaft is positioned in the head rather than in the block.  As we discussed in the previous posts, the L-Head and OHV engines both have the camshaft positioned in the block.

Here are several designations you may see on engines and engine materials and what each one means:

1. OHC (Over Head Camshaft).  This means that the camshaft is positioned in the cylinder head rather than in the block.  If the only designation is "OHC", it generally means that the engine has only a single camshaft.
   
2. SOHC (Single Over Head Camshaft).  Once again, this means that the camshaft is positioned in the cylinder head rather than in the block.  The "S" part of the designation simply means that the engine has only a single camshaft.
3. DOHC (Dual Over Head Camshaft).  Once again, this means that the camshaft is positioned in the cylinder head rather than in the block.  The "D" part of the designation simply means that the engine has two or "dual" camshafts positioned in the cylinder head.

Next time we will discuss the differences between OHC and OHV.  For a discussion about this topic, visit the Superior Power Equipment Forum.

Until then, keep your engines running folks!