ADV Check

[Spitty]

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Originally posted by TurboJim:
Gee Filter guy thanks for the links!

Spitty here is your answer about the ADBV being the cause of your oil pressure warning light....

From FMC TSB 83-2R:
( http://www.filtercouncil.org/techdata/tsbs/83-2R.html )

On some engines the filter is mounted in a position which could allow the oil in the filter to drain back to the crankcase when the engine is stopped. This would be the case for the filter mounting shown in Figure 2 where the filter is horizontal and is above the level of the oil in the crankcase. Normally, it takes approximately five (5) seconds for the pump to fill the filter after the engine has been started, during which time the warning device will indicate no or low oil pressure.

To prevent the engine from operating without oil pressure for this period of time after start up, the filters designed for these mounting positions contain an anti-drainback valve. This valve is usually in the form of a rubber gasket which allows the flow of oil through the filter in the normal direction, but when the engine is shut down, it prevents the oil in the filter from draining back to the crankcase. If the warning indicator remains on for longer periods after the filter has been on the car for some time, replacing the filter is recommended.

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[Winston]

Spitty,

I have a difficult time choosing which emoticon to choose when I post a message, but I am in awe of your last message when you wrote nothing and only included an emoticon.

I hope my posts don't P anyone off. I certainly don't take anyone else's comments personally.

 

[Winston]

Filter guy.

I am confused by your post.

You say

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It is not the differential pressure "across" the media that opens the by-pass valve.

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And then you say;

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It is the differential between the incoming oil and the oil pressure on the clean side of the element.

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These two statemens are synomomous?!?!

Then you say;

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As there is zero oil leaving the filter when you start the motor, the by-pass opens up immediately.

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Why do you think there is zero oil leaving the filter? Some oil will go through the filter.

Then you say;

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As the oil goes through the media sufficiently, then the by-pass shuts off.

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I agree with that.

Then you give a quote from the Oil filter council;

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It monitors the difference between the oil pressure coming into the filter and the oil pressure leaving the filter.

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Doesn't that confirm what I said?!?! I feel I am beating a dead horse, but I was left confused after your post.

 

[Filter guy]

I bet on that horse once..

Winston..you took..or am I wrong..exception to when I said it is the amount of oil coming into the filter v what is going out.

You've gone into longwinded explainations about "across" the media.

And yes some oil..depending on viscosity..will get through in most circumstances.

But riddle me this batman...if the media is totally plugged, how can there be a 12psid drop "across" the media.

The media is but one component part of the element. You have the tension spring, the metal endcaps, the center tube, and the shell/can itself all of which create a no flow path. ( Yes the center tube has holes but it also has solid sections which force the oil to redirect itself). The by-pass valve is only concerned with the flow in v flow out differential.

 

[Spitty]

I think we all now understand the principal, it's just the Language is getting in the way.
Good job we are just Guys talking about oil filters, if we were Heads of State, we'd have a war by now!

 

[Filter guy]

Well Winston posted this on the 18th:

No, this is absolutely not true. The relief valve does not open until the differential pressure between the upstream and downstream side exceeds the valve set pressure (around 12psi - varies with each filter). Upon start-up the oil tries to flow through the filter media, if it requires more than 12psi(assuming that is the relief valve pressure for this filter) to flow through the filter the relief valve will open as necessary to allow the flow through the filter canister.
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Now I claim it is the differential between what goes into the filter and what comes out.

It sure seemed to me Winston was claiming it is the differential..across the media.

His and my statements are not the same thing.

So someone is misguided.

I still maintain that there is no oil coming out of the filter at startup. While the oil is attempting to get through the media, by that time the incoming oil v outgoing ( none) has already opened the by-pass valve. Then as oil does start to flow through the media it joins in with the unfiltered oil downstream. Once the differential pressure equalizes below the minimum opening valve pressure setting, then 100% of the oil goes through the element.

In any event the by-pass does open up..

And not to belabour the point but at start up the oil pump sends a higher flow rate to the filter. Generally 60-80psi. The oil pump regulating valve opens to allow the higher flow because there is no oil returning from the engine to the sump. As the oil returns to the sump the regulating valve equalizes and settles in on a 40-45psi flow rate which is the normal flow rate.


So the filter see a higher incoming pressure rate at start up. Which fills the filter quicker if new or the anti-drain fails.

Which gets back to the point of the engine oil light staying on for 3 seconds or so... It doesn't take long to fill a filter with oil.

 

[Winston]

I had a good time discussing this Filter Guy, and I definately have no hard feelings. It made me really think about what happens in the filter at various times of engine operation. I think spitty is right, we both have a pretty good idea what is happening, but the language gets in the way. My posts often get long winded due to the difficulty of explaining things vs just looking at a sketch. At this point I am going to quit trying to argue the various filter flow issues.

 

[Brian Barnhart]

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In any event the by-pass does open up..

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This is incorrect. I could go into a long explanation, but basically an empty filter offers essentially zero resistance to flow. No resistance to flow means no (differential) pressure. The only way to open the filter bypass is for the filter to offer enough resistance to flow to build up differential pressure. And that won't occur with an empty filter.

There is a lot of confusion at this site as to the operation of oil filters, and the various valves. A summary of the oiling system should be posted somewhere on this sight, especially concerning ADBVs, oil filter bypass valves, and oil pump bypass valves. Confusion over these three valves happens here on a regular basis.

 

[novadude]

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This is incorrect. I could go into a long explanation, but basically an empty filter offers essentially zero resistance to flow. No resistance to flow means no (differential) pressure.

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FINALLY!!!

I was wondering when someone was going to realize that it takes less pressure to fill an empty can than it does to push against a bypass valve spring!

Friends, that bypass valve will not be opening until the filter can has filled with oil, and that is FACT! (unless someone can prove me wrong

). Even if you are filling the filter at such a high rate that the media cannot "keep up" (unlikely at idle speeds during start-up), you still have the canister volume on the inlet side of the media that must be filled before that valve even thinks of opening.

 

[Winston]

Why do you think the can would be empty? We are talking cold start-up. Not cold after oil change. As long as the ADBV is working the the filter will be full of oil.

 

[Winston]

I do not think anyone is worrying about whether the bypass valve is open when the oil is filling he filter. What we are wondering about is .... OMG I forgot the whole point of this discussion

Anyway, Gary Allen's mini bypass system has pretty much proven that the filter bypass opens for a short while during a cold start.

 

[novadude]

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As long as the ADBV is working the the filter will be full of oil.

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Yes, but I thought we were talking about what would happen if the ADBV was NOT working. In which case the can would be empty, and it would take longer for oil pressure to build as the pump filled the empty can (like what Winston was seeing).

 

[TurboJim]

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Originally posted by novadude:
I was wondering when someone was going to realize that it takes less pressure to fill an empty can than it does to push against a bypass valve spring!

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The bypass valve opening is based on differential pressure not absolute pressure.

 

[Filter guy]

Winston..it's been fun.

I think if you didn't start off by saying I was wrong we might have had a better discussion on by-pass valves..

Because I think we both know how they work.

I think the semantics was on "across the media". That's where we differ. We both know it's differential pressure that opens the valve.

I, too, was under the impression we were mainly talking about a filter full of oil at start up.

On a filter where the anti-drain has malfunctioned the media is still saturated with oil ( unless the filter is inverted it will not completely drain free of all the oil, so on a horizontal mount there is always "some" oil in the filter even if the antidrain malfunctions ) and with the incoming flow of oil it takes less than 1/2 of a second for the by-pass valve to open.

For those talking about a brand new filter with no oil in it.....what is the oil flow volume entering the filter canister? A filter that takes roughly 1/2 a quart or less of oil to fill, how long at start up does it take to fill the filter sufficiently enough for the by-pass to open? 1 second? 2-3-5-10 seconds?

So while you are correct there is no differential pressure the instant oil enters the "new" filter, i'm curious how long you think it takes before there is enough differential pressure which allows the by-pass to open.

 

[novadude]

That would depend on the GPM output of the pump and the volume of the filter can, and also the flow capability of the media.

 

[Brian Barnhart]

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i'm curious how long you think it takes before there is enough differential pressure which allows the by-pass to open.

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Assuming the filter is relatively new (not loaded with trapped particles or plugged) …

That depends primarily on oil temperature/viscosity. If the oil is hot/thin there won’t be enough differential pressure to open the oil filter bypass valve and all the oil will flow through the element even at start-up.

As the temperature drops and oil viscosity increases you reach a point where oil flow from the oil pump will create enough differential pressure to open the oil filter bypass valve. However, the oil filter bypass condition may not last long.

Given the typical oil filter bypass settings, typical system operating pressures, and oil passage restrictions, I’m beginning to think any oil filter bypassing that occurs will stop by the time the engine’s oil passages are filled. Why? Because I’m thinking full oil passages have at roughly 10 times the restriction of an unplugged oil filter… regardless of temperature.

 

[labman]

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Originally posted by Brian Barnhart:
snip.... I’m beginning to think any oil filter bypassing that occurs will stop by the time the engine’s oil passages are filled. Why? Because I’m thinking full oil passages have at roughly 10 times the restriction of an unplugged oil filter… regardless of temperature. [/QB]

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If the ABDV is working, the filter and oil passages are filled before the engine turns over. That is what it is for. With an 0W- or 5W- oil, it may not bypass at all if you keep the revs down until the engine warms up.

 

[Brian Barnhart]

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If the ABDV is working, the filter and oil passages are filled before the engine turns over. That is what it is for.

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The ADBV is designed to prevent the oil in the filter from draining out of the inlet holes, or possibly to prevent oil from the dirty side of the filter from washing back into the sump. It’s not designed to keep all the oil passages full, nor can it. Roughly speaking, oil will drain out of all oil passages above the level of the oil filter outlet hole. The oil drains out of the passages through the bearing clearances etc.

 

[Winston]

Filter Guy, I know I can be rude, but I was not the first one to say "your wrong." You called me wrong. It did not bother me, in fact, I complimented you for being direct when you called me wrong. Then I returned the favor.