Exactly how does a bypass valve work?

[river_rat]

PSID for the bypass setting is 8-11 on that filter.
Puro has a little higher bypass, but a little more restrictive media so probably not much difference in behavior I'm guessing.

Looks to me that, at least with our modern wee little filters, some bypass is normal when you punch the throttle enough to downshift and pass on the interstate.
On the other hand, if the entire sump is going through the filter 4-5 times a minute at that RPM, and most of it is going through the media, and add to that 90% of the time the bypass would be closed (I run 2200-2500 RPM at 75-80 mph)...does it matter? Won't the filter likely collect any dirt that faster than the engine can collect or generate?

 

[ltslimjim]

^Exactly.

 

[ZeeOSix]

Originally Posted By: river_rat
PSID for the bypass setting is 8-11 on that filter.
Puro has a little higher bypass, but a little more restrictive media so probably not much difference in behavior I'm guessing.


Hard to say if a WIX actually flows better than the PureOne (if comparing same sized filters). Of course the total media area plays a factor in "flow vs. psid" characteristics. The PL14006 that Purolator tested wasn't a large filter ... probably in the "medium size" category.

If the WIX you tested is in the small size category, then that very well could have played a part in seeing bypass action occurring well below redline (plus the oil was at 180 instead of 200 F which is a factor). This is one concern I have as filter makers keep shrinking the filter media area more and more. In order to keep the filter from going into bypass too often (even when brand new - gets worse with use), they would have to make the media flow better, which in turn most likely will hurt filtering performance to some degree.

The PL14006 that Purolator bench tested theoretically wouldn't go into bypass regardless of engine RPM as long as the oil was fully hot. Note that the PL14006 does not have a bypass valve, but instead the bypass is built into the block of the engine, and is set to ~8 psi (typical GM design).

 

[river_rat]

I'm guessing based on media sq. in. etc. I don't know about the Puro bypass. I know the little Wix I use has more sq in by a small amount than the equivalent P1. About 100. The pleats are deeper on the Wix I use because the center tube is smaller.
All I can do is extrapolate based on testing one filter. It was a major pain, so I won't be testing anymore. I feel it answered the question I had for my application.

 

[modularv8]

Originally Posted By: gordonm
More questions:

In various online 'oil filter comparisons' I have read, the bypass valve location shown in the cutaway views of the Bosch filters is considered inferior to valves located at the baseplate end of the filter. The theory is, with the valve located as shown, oil will 'wash' over the filter media when the bypass valve operates, picking up contaminants trapped on the surface of the media and returning them through the bypass valve to the oil pan.

I'm wondering if someone can address this. Is this a valid concern? There must be some other advantage to the construction shown in Bob's post that I'm not seeing. Perhaps it's less complex/cheaper from a manufacturing standpoint; perhaps it allows the use of more filter media.

Another point: In the SHO oil filter article (don't have a link handy), the author claimed that this type of construction did not meed Ford specifications. Is this true? Do any other manufacturers spec filters with baseplate-mounted bypass valves only?


Yes, Ford specifications require the pressure relief valve to be on the threaded end of the filter. In the winter time, bypass valves will almost always open upon starting when the engine/oil is cold. Also since it takes an engine longer to reach peak oil temperature when the ambient temperature is cold (~less than 40F), the filter is more likely to go into bypass when accelerating.

As for whether it makes a difference in wear rates, you first have to believe that an engine ingesting a load of contaminents accelerates wear and bypassing at the dome end does this. If you study the dome area of a used cut-open oil filter (your own or from pictures posted in the oil forum), most often you will see specs/debris with the naked eye. What is more important is what you can't see; the contaminents in the sub 20 micron range. Ford claims that this is where the real wear causing particles reside and calls it sludge (oil mixed with organic and inorganic wear causing particles). Engineers claim that bypassing dirty oil during cold engine start-up is part of the accelerated wear that comes from cold starting.

As far as diminished wear from higher filter efficiencies, there is a decrease in wear but it is insignificant (ie, going from 90%+ to 99% @ 20 microns). I don't have exact numbers or references for what I am saying, just speaking from my work experience at SWRI. The focus seems to be not on SPFE but rather MPFE, where oil filter bench testing better simulates the real world.

In practice, several major automotive manufacturers have the pressure relief valve on the dome end for their OEM oil filter, but it does not seem to make a difference. I guess the same could be said about higher efficiency filters.

Speaking only about Ford, in my opinion it is better to go with the OEM filter (Motorcraft). Especially, where Ford uses a high volume oil pump (new cars/trucks with VCT).

 

[Sayjac]

Quote:
Yes, Ford specifications require the pressure relief valve to be on the threaded end of the filter.....
Curiously though, not all Motorcraft filters, I'm assuming also used in FoMoCo vehicles, have thread end bypass. Some have dome end.

Same with some M1 filters.

Based on my reading here, don't see it as a big difference either way. The one thing I have noticed is that thread end bypass in some Wix filters in particular with pics posted here, have seemingly smaller media area because of space required, than a comparable filter app with dome end bypass. Whether that makes any difference?

 

[modularv8]

Originally Posted By: sayjac
Quote:
Yes, Ford specifications require the pressure relief valve to be on the threaded end of the filter.....
Curiously though, not all Motorcraft filters, I'm assuming also used in FoMoCo vehicles, have thread end bypass. Some have dome end.

Same with some M1 filters.

Based on my reading here, don't see it as a big difference either way. The one thing I have noticed is that thread end bypass in some Wix filters in particular with pics posted here, have seemingly smaller media area because of space required, than a comparable filter app with dome end bypass. Whether that makes any difference?

Not sure which if any Motorcraft filters have dome end bypass valves. Here is a comparison PPT from Ford comparing its Motorcraft oil filters to aftermarket,

Motorcraft Oil FIlter Cut-Away Comparison Kit

What is interesting, is that Wix/Napa Gold has moved the bypass location to the threaded-end (at least for the FL820s alternative), though it doesn't look like the typical bypass valve construction. Some on BITOG have posted noticing the change.

 

[Sayjac]

Very familiar with the Motorcraft thread end design, however the linked comparison doesn't give an entirely accurate picture, imo. I will do some research and find some Motorcraft apps that use dome end bypass, but here's one of them now. Several other Mc dome end dissections have been posted here previously. I have nothing against Mc filters, solid filter. But when a statement is made saying FoMoCo/Mc specs thread end, but makes dome end too....

Also Wix did go to the dome end bypass in the new plat. filter that, in addition to Donaldson/FG looks very similar to the Amsoil filter cut away. It too uses dome end bypass. The Wix/NG remains unchanged afaik.

Edit, The FL-910 uses dome end bypass shown here.

 

[modularv8]

Originally Posted By: sayjac
Very familiar with the Motorcraft thread end design, however the linked comparison doesn't give an entirely accurate picture, imo. I will do some research and find some Motorcraft apps that use dome end bypass, but here's one of them now. Several other Mc dome end dissections have been posted here previously. I have nothing against Mc filters, solid filter. But when a statement is made saying FoMoCo/Mc specs thread end, but makes dome end too....

It is interesting that the Motorcraft FL-1998 does not have a Ford application, only for Subaru. I see the FL-910 fits on the 2.3L engines on the Focus and Escape/Mariner. Wonder what is different about those engines. I used to have a Ford ranger with the 2.3L and I remember the oil filter installs vertical.

BTW, the statement about FoMoCo specs threaded end comes from Motorcraft's website/promotional material and Ford part publications, not mine.

 

[modularv8]

The common denominator with Motorcraft filters without the threaded-end bypass, is that they have applications to engines not designed by Ford but by Mazda (FL910, 2.3L Mazda's MZR design) and (FL822, Probe 2.5L V6 made by Mazda) or are made for non-Ford applications; GM's, Nissans, Honda, etc. BTW, the FL910 has a terrible micron rating of 50% efficiency at 35 microns according to Motorcraft literature.

 

[Sayjac]

Yeah the first pic was the first I could find of Mc dome end, but the FL-910 has Ford apps. Also a member posted an FL-822 dome end here a couple years ago, but that may have now been superceeded by the 910.

As for the statement, it's cool. I was just pointing out that not all Mc filters, even for Ford's, are thread end bypass. I suspect the 910 is a smaller filter based on the vehicle applications, perhaps that is a factor in the dome end bypass decision?

 

[modularv8]

Since Mazda designed the engine, I think Ford/Motorcraft just took Mazda's specs for the FL910.

 

[modularv8]

Looks like all Motorcraft filters for Ford designed/ manufactured engines have oil filters spec'd with the thread-end bypass location. The FL910 (originally spec'd for Mazda engine) was replaced a while back by the FL910s (thread-ed bypass).

Ford claims it is important to have the bypass located on the base-plate side.

 

[BodybyFisher]

Thank you in advance for reading and considering my options here.

Well this thread tells me I am in trouble. But maybe you guys can calm my fears, but maybe not.

I have a 97 Eldorado ETC that has an engine that was rebuilt about 45K miles ago by Jasper (prior owner had the job done).

The Northstar timing chain is steel. A timing chain tensioner failed whereas the plastic (not sure what kind of material it is so I am calling it plastic) that covers the aluminum alloy guide came off allowing the aluminum alloy guide to contact the steel timing chain and the steel timing chain cut into the guide.

This undoubtedly distributed metal filings around the engine. I can confirm that as I have scoring in my #8 intake lifter bore and I believe it is out of spec for clearance which is suppose to be .001 to .003. I am in the process of miking the lifter bores. It makes sense that the debris would go toward the #8 lifter bore as they are at the end of the oil galley in the head. I was getting a misfire (only at idle) in number 8 and I believe the clearance is too large and the lifter collapsed at idle when the oil pressure drops and therefore unable to compensate for the oil leak occurring due to the out of spec lifter bore clearance. My testing should disclose the out of spec clearance but suffice it to say that I can ROCK the lifter in that bore.

At highway speeds the misfire light went out and the misfire stopped.

The head is off the car and was sent to a machine shop. They could find no valve problems in #8. I found the timing chain guide problem/damage during removal of the front head.

I have not cut open the oil filter but after considering oil filter bypassing occurring during cold starts and hard acceleration debris definitely gets by the filter on bypass.

My gut is this engine is a boat anchor needing a teardown and cleaning and inspection. The debris undoubtedly got into the main and rod bearings and its a matter of time before damage is done.

When I find the photo of the damaged guide I will post it.

The tops of the lifters have grooves cut into many of them as if the lifters were not rotating (probably from debris jamming them from turning)

1) how do you guys cut an oil filter open without causing filings?
2) is there a way to flush out an engine and get collect debris?
3) Given that the guide is some type of aluminum alloy its not likely attracted to a magnet.
4) I have a replacement head from a scrap yard and plan on replacing the lifters in the rear head.

Ideas would be greatly appreciated. Please no laughing or flaming of the Northstar or Jasper, this is painful enough. I believe this problem was misdiagnosed by a mechanic who did a leak down test and stated that the problem was a bad intake valve not closing fully in #8.

 

[dnewton3]

Generally you can use an exhaust pipe cutter such as one from Harbor Freight to open the filter. There are more expensive ones, but those are praised by many for the job they do and the cost.

As for flushing the engine, it's generally only going to be done with the engine oil pump; the issues are already there are you've shown. short of a complete teardown and wash, you'll have to count on repeated cycles to have the lube and gravity pull them down to the pan. A magnetic oil pan bolt can help reduce what may make it back to the screen on the pump pickup.

Al will not be attracted to the magnet; you're correct. So only micro analysis would tell you what it is as confirmation.

I would think no one would flame Jasper; they are a pretty well respected remanufacturer. If it can be shown that their rework was at fault, they may help with their warranty, if still in force.

 

[BodybyFisher]

Thanks dnewton3, I have a Harbor Freight nearby that's a good idea, thanks.

I plan to replace any of the tensioners that have a "plastic" wearing or rubbing surface. I don't think this was a common failure so I don't want to take any chances with the other tensioners failing like this. There is a wide quality range of parts out there maybe a cheap aftermarket part was used.

It is my understanding that that this 32 valve engine with 32 rubbing element 33mm lifters is subject to significant oil shear. The engine calls for 10W30 mineral oil according to the manual. Since the engine was rebuilt the owner has used 5W30 Mobil 1 and he outright refused to use 10W30 Mobil 1 as he was convinced he could feel the difference. Against the dealer's recommendation he made them use 5W30 Mobil 1.

It is my understanding that synthetic oil flows better than mineral oil. If my lifter bore clearance was out of the .001 - .003 spec and was say, .005 or .006, a synthetic oil would flow through this "leak" more readily than mineral oil. Please comment on my thinking. I came here because you guys know oil. If in fact the clearance was out of spec, at idle oil would leak AROUND that lifter instead of filling the lifter, causing a misfire. In addition, at idle because of this leak, the oil pressure to all lifters would be decreased. I am not sure if that lowered oil pressure would affect the rear bank, but my gut says yes. I must say however that there was NO oil pressure warning at idle.

At idle the Northstar oil pressure drops to less than 10 PSI, in a good engine. We have seen Northstars set a low oil pressure light at idle and as soon as you get off idle the light goes out. I don't think the oil light turns on till less than 6 or 7 psi. I plan to check the oil pump for scoring and clearance and put an actual oil gage on the engine when I reassemble it to see what is going on.

I believe the "better flowing" synthetic 5W30 oil contributed this misfire problem permitting freer oil blow-by the lifter due to the out of spec clearance.

Does anyone know if there is a chart comparing the flow spec for 10W30 mineral oil to 5W30 Mobil 1? I have seen a flow chart comparing all of Mobil 1's oils but I have not seen that for mineral oil. I am curious about the superior flow characteristic of synthetic oil vs mineral oil.

 

[ZeeOSix]

Dang, the time machine got fired up.

 

[ZeeOSix]

Originally Posted By: BodybyFisher

It is my understanding that synthetic oil flows better than mineral oil. If my lifter bore clearance was out of the .001 - .003 spec and was say, .005 or .006, a synthetic oil would flow through this "leak" more readily than mineral oil. Please comment on my thinking.


Not if the two oils are the same viscosity when hot. The "superior flow characteristics" of a full synthetic oil is really noticeable at very cold temperature. I'm betting the viscosity of a 5W-30 conventional oil vs a full synthetic oil at 200 deg F is pretty much equal.

 

[BodybyFisher]

Thank you Z06!

 

[BodybyFisher]

Found a photo of the damaged timing chain guide and how it is being cut into by the timing chain

Here is the scoring I spoke about in the lifter bore

Top of lifter damage,