DIY Bypass Filter and Preluber Costs

[Fitzhugh]

OK, I think I got enough of this down to start tallying up parts lists and costs.

First, could I get a review of the correctness of this drawing? I sketched up the overall plumbing setups to use to compare.
DIY Bypass and Preoiler

(I left it as a URL because I can't get it to show up as an image in the preview panel.)

The idea was to add a bypass filter by one of the two methods, either tapped at the oil pressure sender or at a sandwich adapter. From there, the addition of a preluber pump is shown.

I didn't show an accumulator because I have concerns about their capacity in pre-oiler startup applications.

So - is the plumbing correct? If it is, I have an Excel spreadsheet with the costs of five options for building a bypass filter with and without a preluber.

 

[slalom44]

They look fine, but here are a few suggestions:

With a preluber, I don't recommend that you tap into the oil pressure sender port unless it is measuring the oil pressure pre-filter. Most engines measure the pressure post-filter. If you tap into a port that is post-filter, you will back flush your oil filter every time you turn the prelube pump on, then the oil filter goes into bypass when you start a cold engine, washing the newly-backwashed sediment into your engine.

If you tap into the oil pressure switch port, I suggest that you hook up a braided hose there, and attach the tee at the other end of the hose. Vibrations from the engine will otherwise cause the tee fitting to fatigue. I suggest that you do this anyway, and attach both the engine's oil pressure switch and an oil pressure sender for a pressure gauge you should install.

Before you do this, I suggest that you remove the pressure switch and the oil filter, and pour a little oil down the pressure switch port. If it comes out of the center tube of the oil filter mount, you know your switch is measuring post-filter. This is good to know so that you know whether your pressure gauge is measuring your actual post-filter engine pressure.

 

[Fitzhugh]

quote:

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With a preluber, I don't recommend that you tap into the oil pressure sender port unless it is measuring the oil pressure pre-filter.

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I completely agree. That's why I only showed the preluber connections as coming from the oil filter sandwich. The idea is that you hook the preluber to the incoming side of the full-flow filter so that the preluber output is forced through the main filter as well. I would be concerned that the oil pressure sensor is not a high-enough flow place anyway for prelubing.

I only showed the bypass filter connection in one instance connected to the oil pressure port. The small flow rate should not disturb the flow there, I think.

The only reason to include that was for economy anyway. A Tee costs a few bucks, a sandwich adapter is $20 to $40. I prefer the sandwich, but the Tee does save some money.

I'm going to write up this mess and put it on my web page, so I wanted the comparison.

quote:

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If you tap into the oil pressure switch port, I suggest that you hook up a braided hose there, and attach the tee at the other end of the hose. Vibrations from the engine will otherwise cause the tee fitting to fatigue. I suggest that you do this anyway, and attach both the engine's oil pressure switch and an oil pressure sender for a pressure gauge you should install.

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Good suggestion. I'll rework the drawing.

quote:

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I suggest that you remove the pressure switch and the oil filter, and pour a little oil down the pressure switch port. If it comes out of the center tube of the oil filter mount, you know your switch is measuring post-filter. This is good to know so that you know whether your pressure gauge is measuring your actual post-filter engine pressure.

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Another good suggestion. Thanks!

 

[Gary Allan]

I would think, that unless your filter doesn't have a ADBV, that the post filter tap point wouldn't present any issues. The backflushing effect is surely the reason you have an ADBV ..but I would think that the traditional oil pump should inhibit rapid backflow (some may).

 

[Fitzhugh]

Here's the reasoning I used: I wanted to make sure that since the preluber pump is sucking from the dirtiest place in the oil sump, it did not pump that unfiltered grit and gook into the engine without at least one chance at a pass through a filter. Hence the output of the pump goes to the pressure side of the oil pump into the filter, goes through the filter into the engine. Admittedly, the full flow filter may itself bypass and let the dirtiest oil through, but I at least tried.

The second choice would have been to put the preluber pump on the output side of the full flow filter, but add a second, dedicated preluber filter to the preluber pump output. When I got that throught enunciated to myself, I giggled and envisioned about six spinoff filters of various sizes inside an engine compartment and said "OK, we won't be needing that. So I decided to try to force it through the full-flow.

If I follow you correctly, the ADBV would not help with the back flow through the pump when the engine is operating normally and the pump is off.

Come to think of it, I know that the Shur-flo pump has a check valve in it. I suspect that the gear pump I found does not backflow. That would be great. I'm getting spreadsheet prices from about $70 for the minimum cost bypass setup to about $300 for a deluxe, all-hydraulic-hose bypass-and-prelube system with the gear pump. There's that check valve in the deluxe, and it's estimated at $15 now, so getting the price down a bit would be nice. 'Course, I'm still looking up prices.

 

[Gary Allan]

quote:

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If I follow you correctly, the ADBV would not help with the back flow through the pump when the engine is operating normally and the pump is off.

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My thoughts were that any backflow through the filter to the sump via the traditional pathway will be nil (very slow) due to the ADBV in the ff filter. This is assuming that your pump/preluber has it's own modality to prevent backflow. Even without a ADBV, I think the volume of your pump will be enough to pressurize the system without difficulty.

Now the preluber drawing dirty oil ...that's a factor that I'm uncertain of the what to assign an anxiety factor to.

If you browse through various filter studies, you'll often see reference to lame ADBV's as "allowing dirty oil back into the pan". The end of the statement is missing is, "back to the exact same place it came from ..to a sump with oil that is in exactly the same condition". It kinda got a catchy internet legend of importance to itself that is bigger then it can be in real life. The ADBV is merely a divider ..it could be located in various places and accomplish the same task/function. It prevents, as stated, rapid backflow, however slight, from backflushing the media. Oil before the filter and after the filter has very much the same appearance. There is no distinct difference pre and post filter. Sure, one or a few (hundreds maybe) of appropriate sized particles my be trapped on this pass ..but more than likely ..only a % of them. Even with a bypass, you're only filtering about 10% max ..so the pre-post oil condition, although very clean when compared to just a standard full flow, will still be 9/10th identical to what it was before the cycle began AT BEST. That is, I wouldn't (this is just me) fret any random chance the oil I'm pulling out of the pan is unsuitable for pumping. Naturally using a sandwich adapter to plumb your bypass filter will allow the preluber to be plumbed (I may have missed this in these lengthy posts).

[ January 31, 2006, 12:03 PM: Message edited by: Gary Allan ]

 

[slalom44]

This may be a moot point, but I'd like to make a few comments:

Hooking up the preluber pre-filter will allow you to purge any air in the full flow filter resulting from a leaky ADBV. A post-filter hookup would not purge this air pocket.

Besides - If you plumbed the preluber post-filter, you'd be taking oil from the very bottom of the oilpan, and pumping it right into your engine without going through a filter. If I'm anal enough to have this setup, I just couldn't do this.

The Shur-flo pump I mention is giving me an oil gauge reading of around 20-25 psi, and that's after passing through the spring-loaded valve of an Amsoil BMK-13 remote setup. My oil pressure gauge definitely reads post-filter, so I know the engine is getting adequately prelubed and the filters are being purged of air. On cold days after the car has been sitting for about a week, it takes around 30 seconds for the preluber to build pressure. That means there's a lot of air in the system.

 

[Gary Allan]

Oh ..in a remote mount (ff) ..sure. There's no reason why not to tap it in there. If your remote mount is mounted above the normal ff filter's height ..then your lines probably empty back ..and the filters drain forward when the engine is off. Not a bad move at all.