I'm in the process of purchasing a 1997 boat with a rebuilt 7.4L engine. The oil filter relocation kit that is installed uses 3/4"-16 spin on filters so I think it an aftermarket kit.
The Mercruiser filters are 13/16"-16. I could not find the specs for the Mercruiser filters, but I was able to cross the Mercruiser part number to WIX 51086. I then searched through all the 3/4"-16 WIX filters to find a filter with similar specs to the Mercruiser filter.
The Wix 1393 or 1393XP (synthetic filter media) look like possible candidates but they have a 30 lb bypass valve and it does not appear the OEM filter has a bypass valve. They all have anti drain back valves. Also I noticed that all the filters that I looked at with 13/16"-16 threads flow 9-11 gpm max and all the 3/4"-16 filters flow 7-9 gpm.
I chose that filter because it is the best quality and had the highest bypass pressure and was the longest filter for the maximum amount of filter media. Any reason not to use that filter?
Edit 3/8/18:
I spoke with the WIX technical representative on the phone today. He did not recommend the XP filters for boat engines. The XP filters were designed for use in cars and light trucks running synthetic oil providing the ability to increase the oil change interval. The synthetic media is backed up by a screen to make it a more robust filter that can withstand the longer service intervals.
The standard WIX filter (equivalent to the NAPA Gold) has a lower micron ratiing than the XP. If you look at the specs for the XP filters you will notice that they do not list the micron rating. As the filters collect particles they actually get better at filtering out smaller particles up to a point. If you are using a filter with a bypass and it gets so dirty that the bypass opens then the filter is no longer doing its job. The bypass may save the engine from catastrophic failure if the filter is changed in time, but while the oil was bypassing the filter, it was causing wear
Also he said don't get hung up on the better flow rating of the filters with 13/16'-16 vs 3/4"-16 nipple. The limiting factor is the 1/2" line going to and from the remote filter assembly. It doesn't matter which one you use, you will only flow 5-7 gpm through the 1/2" line.
Due to the severe duty of a marine engine he said just use conventional oil, and change it and the filter more often. If you used an XP filter it would be a waste because the oil will be spent before the filter. With the larger micron rating of the XP it is probably just getting to the point when it is doing its best job of filtering the oil.
I think that was everything. He was throwing a lot at me at once. If you have questions send them an email. They are happy to help and can explain it better than me.
The Mercruiser filters are 13/16"-16. I could not find the specs for the Mercruiser filters, but I was able to cross the Mercruiser part number to WIX 51086. I then searched through all the 3/4"-16 WIX filters to find a filter with similar specs to the Mercruiser filter.
The Wix 1393 or 1393XP (synthetic filter media) look like possible candidates but they have a 30 lb bypass valve and it does not appear the OEM filter has a bypass valve. They all have anti drain back valves. Also I noticed that all the filters that I looked at with 13/16"-16 threads flow 9-11 gpm max and all the 3/4"-16 filters flow 7-9 gpm.
I chose that filter because it is the best quality and had the highest bypass pressure and was the longest filter for the maximum amount of filter media. Any reason not to use that filter?
Edit 3/8/18:
I spoke with the WIX technical representative on the phone today. He did not recommend the XP filters for boat engines. The XP filters were designed for use in cars and light trucks running synthetic oil providing the ability to increase the oil change interval. The synthetic media is backed up by a screen to make it a more robust filter that can withstand the longer service intervals.
The standard WIX filter (equivalent to the NAPA Gold) has a lower micron ratiing than the XP. If you look at the specs for the XP filters you will notice that they do not list the micron rating. As the filters collect particles they actually get better at filtering out smaller particles up to a point. If you are using a filter with a bypass and it gets so dirty that the bypass opens then the filter is no longer doing its job. The bypass may save the engine from catastrophic failure if the filter is changed in time, but while the oil was bypassing the filter, it was causing wear
Also he said don't get hung up on the better flow rating of the filters with 13/16'-16 vs 3/4"-16 nipple. The limiting factor is the 1/2" line going to and from the remote filter assembly. It doesn't matter which one you use, you will only flow 5-7 gpm through the 1/2" line.
Due to the severe duty of a marine engine he said just use conventional oil, and change it and the filter more often. If you used an XP filter it would be a waste because the oil will be spent before the filter. With the larger micron rating of the XP it is probably just getting to the point when it is doing its best job of filtering the oil.
I think that was everything. He was throwing a lot at me at once. If you have questions send them an email. They are happy to help and can explain it better than me.
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