[GO4BROKE]

Mercruiser Oil Filter Comparison

Current Revision 2.2; February 1, 2004

Original publication date: November 15, 2003

Update: This study has been updated to include pore size and oil flow measurements. Each filter section has raw data measurements and comparisons to the other filters. Two additional filters have been added for a total of 12 filters.

In addition to physical properties, this study now analyzes pore size and oil flow of the filter media using a professional bubble point tester.

To examine all of the detailed regarding the pore size and flow tests, click below:

Pore and flow study details

This project was started to determine the quality of Mercruiser oil filters. This application also pertains to Chevrolet V6 and V8 engines that use the AC Delco PF1218 filter. The objective is not to find out what filter is best for all applications. However, general conclusions can be made for other applications.

An automotive tail-pipe cutter was used to cut the filter housings. This allowed clean cuts without damaging the filters or internal parts. Digital calipers were used to make all measurements.

All recent model 135HP 4-cylinder, V8s, and V6s with remote oil filters use the Mercruiser filter 35-802885T. Originally, the WIX 51086 was going to be compared. Since the AC Delco PF 1218 is a longer filter that also fits this application ten additional filters that mapped to it were compared. Here are the filters (in alphabetical order):

AC Delco PF1218
Baldwin B1428
Fram Extra Guard PH5
Fram Tough Guard TG5
Hastings LF279
K&N 3002
Purolator PureOne PL34631
SuperTech ST5
STP S5
Mercruiser 35-802885T
WIX 51086
WIX 51060
The Merc and WIX 51086 were the only two that are of the original short design. All others are comparable, longer, and larger capacity.

Mercruiser V6 engines without the remote oil filter configuration, use the part numbers below:

Mercruiser 35-883702K
WIX 51036
Hastings LF393
Baldwin B35-S
K&N 2001
AC Delco PF52
All of these filters in this comparison do not have by-pass valves (BPV). The BPV allows oil to by-pass the filter if it becomes clogged. My understanding is that GM/Mercruiser engines have a BPV in the engine itself, so the oil filter specification is to not have a BPV.

These filters also have anti-drain back valves (ADBV). This is a nitrile or silicon rubber seal that stops oil from exiting the intake holes when the engine is not running.

The intent of this study is to be as objective and non-biased as possible and just present observations. The following data was collected. This is included in this MS Excel spreadsheet on the “Filter Data” worksheet.

Number of intake holes
Area of intake holes
Thickness of gasket
Width of gasket seal
Weight of entire filter
Material of ADBV
Number and location of welds
Number of pleats on filter
Area of filter in square inches
Material / design of spring
Notes, positive and negative observations
In addition, the following measurements are made on the filter media:

Average large pore size
Smallest pore size
Oil flow at 10psi and 20psi with 30W oil
This data can be found on the same spreadsheet under the “Bubble Point Testing” and “Oil Flow Test” worksheets.

The bubble point testing was performed using this bubble point tester.

These filters are presented in increasing cost order. The (x of 12) numbers are the rating and comparison to all 12 filters. Higher numbers are better. The filter weight measurements have a one-half weighting. The flow rating is weighted by two. All other measurements have a weighting of one. When two numbers are listed (x-y of 12), this indicates a tie. In this case, an average is used with these numbers for the overall rating. The oil flow numbers below are for the entire filter using the effective filter area (EFA). The EFA is multiplied by the flow of the sample media to arrive at the oil flow number of x ounces of oil per minute at 10psi. While 10psi was used for ratings in this document, 20psi was also tested and is included in the Pore and flow study details document.