FILTRATION
I am assuming you are referring to a spin-on can filter element. Most are built to one or the other of two standards: SAE standard US threads on center post, or ISO with metric threads on center post.
Some common SAE mounts are:
1. ¾-16 center thread (filter about 3 inches OD). This is visually similar to the common Ford/Chrysler engine oil filter mount. Do NOT interchange the two. Engine filters usually have a bypass valve and anti drainback check built into the element. Hydraulic filters have bypass built into the head, not the element. This size filter is usually only for pilot lines and small flow applications. (There are also many other standard threads used for engine oil filter mounts.)
2. 1-12 center thread (filter about 3.8 inches OD) This is by far the most common small flow spin on filter used on mobile or stationary equipment. Almost all the major equipment and filter manufacturers have this in the lineup.
NAPA Gold 1259 is a 10 micron element in 1-12 thread, easy to obtain, around $10, and good quality.
3. 1.50 -16 center thread (filter about 5.1 inches OD) for larger flows. There are different versions (not interchangeable) of metal shell and outer gasket design. Some are flat gaskets, similar to the common 1-12 mount, and some have L shaped gaskets. These are often called Gresen, or Cross, or Donaldson, or Vickers designs, after the original vendors names. I don’t have NAPA cross references for those.
Glass fiber media is much better than cellulose (paper) for filtration efficiency, dirt holding capability before it is filled, and minimizing pressure drop with flow. I don’t have numbers here, not sure if NAPA has a glass fiber element or whether the 1259 is paper or glass.
While the element is off, check the bypass valve in the filter head. They sometimes break up and come apart. Also check the direction of flow stamped on the filter head. Seems like an obvious no-brainer, but I have seen one factory and one homemade unit with filters installed backwards. With flow the wrong direction through the pleats, elements can collapse, block flow, and blow the can/head/hoses/gasket.
kcj
