Oil filter with no bypass valve ?

[rubberchicken]

I cut open a Amsoil EA059 used for my boat, and was very surprised that it has no bypass valve. So I looked up a bunch of competitors- Amsoil EA024, M1-302, Purolator etc. and found that all the cross-referenced filters and larger but compatible sizes also do not have a BPV. The specs at the Purolator site, and some other site I found indicate that no BPV is designed into this spec. I find this very odd, as I thought all high end filters would have a BPV.

Boat is a Mercruiser, 2000 MPI 7.4 L , essentially a marinized version of the L29 454. I am feeling very uncomfortable running a filter with no bypass valve. Boat is only used in temps above 50 F, with 20w50 oil. The Ams EA024 and M1-302 are oversized filters with about 50-75% more capacity.

 

[oldhp]

By-pass valve is in oil filter mount. Look for a small raised metal piece with a bolt holding it with a dime size hole. You can push in on the disc mounted behind it, that's the by-pass valve.

 

[rubberchicken]

Originally Posted By: oldhp
By-pass valve is in oil filter mount. Look for a small raised metal piece with a bolt holding it with a dime size hole. You can push in on the disc mounted behind it, that's the by-pass valve.


Thanks- I had not considered that it would be built into the engine. It has a remote filter adapter: would the bypass valve be at the block side, or on the remote mount where the filter goes ?

Here is a parts diagram of my model-
http://www.mercruiserparts.com/bam/subassembly/31918/2705/240

 

[oldhp]

Should be behind the adapter #7 in the block.

 

[BrocLuno]

If you have enough filter area to handle near full flow with cold/cool oil, you may not want a by-pass valve at all... We regularly block all bypass valves in race motors (do not block pressure relief valves) so that if something starts shedding metal, it all gets caught - well except for what gets tossed around by the spinning crank/windage.

Marine systems are often full flow 100% filtered systems. Ditto for on-board hydraulic systems. It all depends on if your oiling system can flow enough under all conditions.

By-pass valves are for small filters required for space limited areas or cost of MFG constraints where the media area is calculated to be sufficient 95% of the time. Cold starts with thick oil are outside that "nominal running" environment. Also, most operators/drivers are not spinning cold engines to red line.

Fire Trucks, Ambulances, Crash Trucks, etc. - get treated just like race cars. Full flow 100% filtration all the time. They go from stone cold to red line in less than a minute and have to run. Bigger filters are the norm

 

[George Bynum]

Industrial oil filters almost always have the bypass valve in the housing. Only notable exception of which I'm aware are the Hydac return elements.