Integrating bypass filter with preluber

[Fitzhugh]

In researching bypass filters I came across prelubers. These provide oil pressure to an engine before it's started. They are used pretty heavily in big industrial engines, some big trucks, and heavy equipment, like bypass filters. They seem to have about the same prevalence in autos as bypass filtering. Some companies make aftermarket kits.

It occurred to me that a pre-luber taps the engine oil flow in the same places as a bypass filter - the oil sump and a high pressure point. With the same plumbing needed, it might make sense to put a preluber onto a car with bypass filtering.

Prelubers come in two flavors, pump and accumulator. The accumulator is a pressure tank that's filled with high pressure oil through a check valve during normal operation. It releases this held pressurized oil when a valve is opened before the engine is restarted. A pump style simply provides a pump from the sump to the high pressure point.

I have found a gear pump rated for 12Vdc, 1.8gpm that's only about $150. It looks like I could plumb this to the two same lines I plumb to the bypass filer and do an integrated prelube with about the same effort.

I know the economic argument: it will never pay for itself because the car will, on average, die from other causes before engine failure. This is true of bypass filters as well, unless you go to extended drain intervals, probably including oil analysis. I'm interested in the technical discussion of "oh, yeah, I saw that and you have to ..." or "you have to do this to get that working".

It looks like it makes oil changes a breeze as well by pumping the sump dry as needed for changes.

Any thoughts?

 

[slalom44]

If you do a search, you will find that it's been discussed. I have a ShurFlo prelube pump connected to an Amsoil BMK-13 Dual Remote Bypass Filter. This pump cost far less that the one you suggest:
http://www2.northerntool.com/product-1/527.htm

Yes, it does help with oil changes. This pump is self priming, so it can purge your engine and filters of oil, making an oil change mess-free. Having instant oil pressure along with the dual remote bypass setup gives me the best of both worlds. It's way overkill, but it makes for a great conversation piece!

I have had this setup on my car for about a year and a half.

 

[Fitzhugh]

Hi, slalom, and thanks for the pointer.

I read the search results, looks good.

I did consider the shurflo pumps early in the process, and only discounted them because of the 170F rating. The gear pump is rated to 150C as all the parts except the seals are bronze or stainless. But your experience certainly counts!

I spent a long time looking for pumps.

I'm thinking that the better way to plumb would be to remote the oil filter. A couple of judiciously placed check valves lets you pump the prelube oil into the main filter, which is where you'd like for the bottom-of-sump stuff to end up anyway. Then the "high pressure point" is the input to the main filter, the "low pressure point" is the hose to the sump.

So then it becomes
- remote (main) filter adapter on block
- hose from block adapter through check valve to 3-way at high side of remote filter
- hose from prelube pump through check valve 3-way at high side of remote filter
- hose from bypass filter to 3-way at high side of remote filter

Which takes care of all the high pressure side. On the low side of the main filter
- hose from main filter low side to low side of remote (main) filter adapter on block
- hose from oil sump to Tee at bottom of prelube pump
- hose from bypass filter to Tee at bottom of prelube pump

I think that gets the engine oil pump and the prelube pump outputs filtered through the main filter before going into the engine. It gets the bypass filter connected to the high pressure side for its trickle of oil. IT gets the bypass and prelube pump low sides connected to the sump drain.

I see that I left out the oil change arrangement. That works with a two-way valve between the prelube pump and the oil filter high side.

Does that make sense?

 

[slalom44]

It makes sense and is similar to my setup, but I'd like to make a few suggestions:

If you use the ShurFlo pump. you don't need any check valves. The Shurflo pump has a built-in check valve. You don't need a check valve between the block adapter and the tee on the high pressure side because oil can't flow backwards through the engine's oil pump.

Also, consider hooking up an oil pressure gauge and a LED showing you the prelube pump is running. With all that extra plumbing, you really want to know that everything is working right.

The LED is nice because I have forgotten to turn the prelube pump off. The ShurFlo pump has a high-pressure cutoff switch so it turns off automatically after you start your engine. But after the engine warms up the oil pressure drops low enough to kick the pump back on. The LED lets you know that you forgot to turn the pump off.

 

[Fitzhugh]

quote:

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If you use the ShurFlo pump. you don't need any check valves. The Shurflo pump has a built-in check valve.

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Good point!

quote:

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You don't need a check valve between the block adapter and the tee on the high pressure side because oil can't flow backwards through the engine's oil pump.

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Ah. I didn't know that. One check valve on the preluber pump is sufficient.

quote:

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Also, consider hooking up an oil pressure gauge and a LED showing you the prelube pump is running.

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I like that as well.

Gary Allen suggested I plumb with SAE J1019 hose, which is normally used for transmission coolers. That lets me use barbed fittings, which are cheap.

Any thoughts on that?

I'm probably going to plumb the lowest couple of feet with steel line to make road hazards less of a hazard as well.

 

[slalom44]

I'm not well versed in my hoses, so I can't tell you much about whether SAE J1019 is appropriate. I used the hose that came with the Amsoil unit (which is extremely strong) and I bought some braided stainless lines from Jegs and attached the appropriate AN fittings for downstream from the prelube pump. Between the oilpan and the prelube pump the oil pressure is very low, so I just used some relatively flexible black hose I picked up at a local auto parts store and some barbed fittings.

Since my engine generates oil pressures up to 95 psi (Honda S2000), I wanted to make sure I had good hydraulic hoses and connectors. It was tough to get the leaks mitigated at first but after a few weeks of tweaking, it worked great. I haven't had any leaks since.

I like your idea of using steel lines down low. Just make sure that you don't put something together rigid, resulting in metal fatigue.

You can pick up some good hydraulic stuff at www.batinc.net. That's where I got my drain plug replacement fitting which I connected to a barbed 6AN fitting. This made it relatively easy to disconnect for oil changes.

 

[johnd]

For those of you with accumulators, I have a question: Seems to me that the following, engine oil pressure high-oil flows into accumulator, engine oil pressure lows out, right? Seems to me that if one started with the correct amount of oil in the pan, a full accumulator would result in a low oil pan level at high oil pressure-right when you would need it. If you added accumulator capacity to the pan (over filling it) at low oil pressure you would risk hitting the oil with the crank due to over filling. Make any sense? How much do those things hold anyway? Seems to me that less than a quart wouldn't do much in the way of pre-oiling and certainly more would risk overfilling in low pressure situations. Comments?

 

[t-squared]

Accumulators work great on dry sump type oiling systems but get a bit tricky with regular oil pan systems. You can pressurize the can at shut off and use it as a pre-oiler at the next start-up. After you pre-oil just shut off the valve so the system doesn't lose any oil refilling the can during running.

 

[Fitzhugh]

What I read of accumulators is that they work in two different modes, pre-lube and emergency oil.

The emergency oil was for times when the oil in the sump was thrown away from the pickup tube by G forces in maneuvering. The accumulator stepped in with a non-G forced squirt of oil.

The preluber application was that there was a check valve going into the accumulator and that the highest oil pressure your engine hit was stored in the accumulator. There's a mechanical or electrical valve that you open just before starting the engine that lets the pre-pressurized oil squirt into the engine.

My problem with accumulators, and why I decided that pumps were better, is the oil capacity question. Johnd, you're right on with the accumulator needing to have a goodly capacity to fill things up, and then that makes for an oversupply of oil in the sump until the oil pump starts filling the accumulator again. There may be enough freeboard for enough oil to pressure the engine, but I don't know how you'd determine that.

An accumulator with too-small capacity of oil **would** make for a neato amulet to ward off the abrasive spirits, though. I guess.

 

[Gary Allan]

quote:

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C5E Hose
For air brake hose, power steering, fuel filter, engine and transmission coolant lines and hot +149°C (+300°F) lube lines. Recommended for diesel engine flexlines.

• Meets DOT FMVSS 106-74 Type AI and SAE J1019 hot oil circulation test.
• 300 to 1,500 psi working pressure.
• One braid high tensile carbon steel wire over polyester braid.
• Textile braid impregnated with rubber on black cover.
• Nitrile tube.
• Sizes 3/16" through 11/8" I.D.

Uses C5E type field attachable or permanent couplings.

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[Fitzhugh]

Gary, once again, thank you for the pointer.

The C5E/SAE J1019 stuff looks perfect. Medium to high pressure, high temp, field installable fittings, and in regular use for the purpose.

I'm getting to the point that I think I'll write down the recipe.

Thanks so much to all of you for your helpful guidance.