Bypass Oil Filter

[Gros Ventre]

The Bypass filter is not in series with the main oil flow and the pump puts out plenty of flow so the engine sees no reduction in flow. There needs to be an orifice to restrict flow, this is really more for the filter as in order to be a fine filter it needs lower flow. Recall that as a positive displacement pump, its output varies with engine rpm (eg double the rpm, double the oil output). So the pressure at the setpoint is controlled by the spring loaded dump valve. As you go up in rpm the output of the pump goes way up, but that dump valve flows whatever it needs to keep pressure at design.

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[Gros Ventre]

"Don't forget to use Hi Temp thread sealant on the 1/8" NPT threads."

Also, if you put in the -04AN Orifice fitting mentioned, or one similar to it, Use thread locker when you thread the orifice into the fitting proper.

 

[Gros Ventre]

I think this also answers one of my main questions: will a finer, therefore higher resistance, filter just decrease oil flow and therefore have a net negative effect? It sounds like the pump has the ability to put out far more flow/pressure than the lubrication system needs even at redline, such that a higher resistance filter would simply result in less use of the bypass valve. Is that correct?

The way a positive dispalcement pump works is it puts out flow proportional to rpm. It will develop whatever pressure is needed to generate that flow. In other words it'll either break something if flow is blocked or stall the engine... So in this case the flow going to the bypass filter is in addition to the main lubrication flow, the pressure regulating valve will pass a little less oil, and both flows are sufficient to operate the engine properly.

 

[Gros Ventre]

Dumb question, but do you feel the smaller micron filter will do a lot for the life of the engine compared to normal oil changes? Of course the normal oil filters can only catch so much.

I guess I've never look too much into bypass filters, catch cans, etc. Perhaps it'll be beneficial under extreme use cases or if you plan on keeping the truck for a long time and putting tons of miles on it, but normal day to day I'm not sure. I'd imagine it'll be better than not having it.

Suppose you could have a lubricant that had zero particulates or wear products in it... a perfect oil! What would the life of the engine be? How about that MPG? I can only speculate. The Navy on its ships does oil analysis to get long lifetimes out of machinery, to a good effect. And it runs lube oil purifiers on major equipment essentially 24/7...

 

[Blueshound]

You should post this over at BITOG and see what folks have to say. Interesting project, I can't see a downside assuming it doesn't leak or catastrophic self destruct.

 

[Gros Ventre]

I've had these on three other cars. The 92 Suburban, bought new, went 30 years on original engine. Still getting 3,000 to 4,000 miles to the quart. Oil leaks have to be paid attention to. I also do these as part of an oil analysis program.

 

[Gros Ventre]

You should post this over at BITOG and see what folks have to say. Interesting project, I can't see a downside assuming it doesn't leak or catastrophic self destruct.

BITOG?

 

[Blueshound]

BITOG?

https://bobistheoilguy.com/forums/

One of the oldest auto related forums around.

 

[Gros Ventre]

https://bobistheoilguy.com/forums/

One of the oldest auto related forums around.

Yeah, know about him. He's got stuff about bypass filters. My setup would be old news over there...

 

[amschind]

The way a positive dispalcement pump works is it puts out flow proportional to rpm. It will develop whatever pressure is needed to generate that flow. In other words it'll either break something if flow is blocked or stall the engine... So in this case the flow going to the bypass filter is in addition to the main lubrication flow, the pressure regulating valve will pass a little less oil, and both flows are sufficient to operate the engine properly.

Makes sense! Thanks!

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