Exactly how does a bypass valve work?

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My feeling is that the debris managed to get into the lifter bores and jam the lifters from rotating in their bores causing the cam lobe to remain in the same location causing wear. Most of the lifters have this wear.

Surprisingly, the head I got from the scrap yard with 80K miles on it did NOT have these wear lines. Any theories? Remember that the engine was remanufactured 45K miles ago.

The oil was changed religiously by a fanatic and as I stated Mobil 1 5W30 was used. Could this be a sign that the engine shear used up ZDDP or do you think this is this the result of debris locking up the lifters from rotating?

Prior to 1997 before ZDDP was decreased, API service classification SH motor oils Phosphorus/Zinc levels were in the range of 1400 to 1600 PPM whereas as of Sept 2014, Mobil 1 reports the following:

Mobil 1 5W30 900PPM
Mobil 1 5W30 extended performance 900 PPM
Mobil 1 5W30 high mileage 1100 PPM
Mobil 1 10W30 900 PPM
Mobil 1 10W30 extended performance 900 PPM
Mobil 1 10W30 high mileage 1100 PPM

source:
https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide.ashx

There is no question that if I continue to use synthetic it will be one with the greatest zinc content with a PAO base and a dose of ZDDP like GM EOS.

Any thoughts would be appreciated.

If my posts here should be in their own thread, the admin is free to move this, I am sorry if this is located in the wrong thread. Thanks
 
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Your oil filter should remove large particles,so I would say the remanufacturing wasn't done right. If the lifter rocks in the bore that wasn't from particles making some scratches.
 
Thank you.

Do you think that on oil filter by-pass valve ( on cold start up and high RPM romps) permitted debris to escape and enter the engine? The prior owner drove the car hard, often challenging other drivers.

I am trying to find a valve spring compressor that will work on this head and I plan to mic the bores. While I have a 'new' head from a scrap yard I want to know why this failure occurred.

It has been suggested to me that the reman company may have resurfaced the lifters and that they breeched the hardened surface.
 
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Many of the lifters have these vertical scores in them. Keep in mind how hard this material is.

39e6e5a9-bcaf-433c-97f2-106fe3e41011_zpsdae84815.jpg


This lifter came out of the one of the #8 intake valve bores, the one I show above with the scoring. To me, the oil filter HAD to by-pass debris.

108_2411_zps54a01dfe.jpg


Opinions? Thanks for your input
 
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Time to resurrect this thread!

Part of the original question asked about how a bypass valve that's in the block works, it seems as though that was never answered.

I recently ran a Pro-Tec 166 (dissection found _Pro-Tec_166#Post4730782]here ) on my Monte Carlo. This filter comes without a bypass valve, however, the 3.9l does have a bypass built into the block. When pressure reaches a certain point, does it simply redirect oil flow so that it avoids the filter all together? I can't wrap my head around how exactly it operates.
 
That is such a coincidence that you brought this thread back to life as I found it on a search last week and was reading it over again! It's 16 years old!
 
Originally Posted By: RamFan
This filter comes without a bypass valve, however, the 3.9l does have a bypass built into the block. When pressure reaches a certain point, does it simply redirect oil flow so that it avoids the filter all together? I can't wrap my head around how exactly it operates.


Yes, the bypass valve built into the block bypasses the filter completely. GM engines have used a filter bypass valve in the block located at the filter mount for many years. I believe GM has stopped using the in-block bypass valve on their newer engines and have now went with a filter with a bypass valve. Example, the newer Vettes use a filter with a 22 PSI bypass valve.
 
Originally Posted By: RamFan
... Part of the original question asked about how a bypass valve that's in the block works, it seems as though that was never answered.
... When pressure reaches a certain point, does it simply redirect oil flow so that it avoids the filter all together? I can't wrap my head around how exactly it operates.
Yes, but keep in mind that that's the pressure drop (differential) across the filter, not the pressure before (or after) the filter. Assuming the filter is not totally plugged, when the bypass valve opens, some fraction of oil goes through the filter as usual, while the remainder bypasses the filter through that valve in a parallel path ("parallel" in the electrical, not geometrical sense).
 
I just resurrected this thread in a post I replied to last night.
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The WIX oil filter I have on my engine cost $3.14 from ROCKAUTO.COM on clearance. I thought it had the base plate (thread end) bypass valve. Instead, it has the dome end. I prefer the base/thread end.
Also, it's very ironic that this post just came up. Look at what I was reading about as this post was made!

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=309756
_________________________
 
Originally Posted By: CR94
Originally Posted By: RamFan
... Part of the original question asked about how a bypass valve that's in the block works, it seems as though that was never answered.
... When pressure reaches a certain point, does it simply redirect oil flow so that it avoids the filter all together? I can't wrap my head around how exactly it operates.
Yes, but keep in mind that that's the pressure drop (differential) across the filter, not the pressure before (or after) the filter. Assuming the filter is not totally plugged, when the bypass valve opens, some fraction of oil goes through the filter as usual, while the remainder bypasses the filter through that valve in a parallel path ("parallel" in the electrical, not geometrical sense).


That's what kind of confuses me. If the pressure drop across the filter is responsible for whether or not a filter goes into bypass, how is an in block bypass valve able to detect this pressure drop thus bypassing the filter? It would make more sense to me that the in block valve would be measuring the pressure difference between inlet and outlet pressure which would essentially be the same thing as the drop in pressure across the filter.
 
Originally Posted By: RamFan
... It would make more sense to me that the in block valve would be measuring the pressure difference between inlet and outlet pressure which would essentially be the same thing as the drop in pressure across the filter.
That's correct. Why is that confusing? Would it be easier to understand if we replace your word "measuring" with "reacting to"? Whether in the block or in the filter, the bypass valve limits the pressure difference by allowing some oil to bypass the media (and the rest of the filter, too, in the case of in-block bypass).
 
Originally Posted By: RamFan
It would make more sense to me that the in block valve would be measuring the pressure difference between inlet and outlet pressure which would essentially be the same thing as the drop in pressure across the filter.


That's exactly what an in-block bypass valve does. It senses the pressure difference across the filter and starts to open when the delta-p reaches the valve setting. No different than a bypass valve built into a filter. Just a different location.
 
Originally Posted By: CR94
That's correct. Why is that confusing? Would it be easier to understand if we replace your word "measuring" with "reacting to"? Whether in the block or in the filter, the bypass valve limits the pressure difference by allowing some oil to bypass the media (and the rest of the filter, too, in the case of in-block bypass).


Originally Posted By: ZeeOSix
That's exactly what an in-block bypass valve does. It senses the pressure difference across the filter and starts to open when the delta-p reaches the valve setting. No different than a bypass valve built into a filter. Just a different location.


Ok, I apparently have been way over thinking this!
lol.gif


Thanks for the responses.
 
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Originally Posted By: Linctex
... Many years ago when this thread was created,
it was an "assumption" that the bypass valve is open a lot of the time...
....when in actuality, it very seldom ever is.
Many years ago when the testing reported in that thread was done, filters were not as tiny as they are now. Shrinking the filters must have increased the frequency of bypass situations. On another hand, recommended oils are generally thinner now, which would have the opposite effect. An update would be interesting.
 
Originally Posted by JimMueller
Are these aftermarket LS engine oil bypass parts quackery or worthwhile, if you're using a filter with an internal bypass?

https://www.saccitycorvette.com/BilletBypassPlug.html
https://www.saccitycorvette.com/Billet-BarBell.html

https://www.youtube.com/watch?v=y8WpGE6SqXw
https://www.youtube.com/watch?v=4Hi9XMQ1S_4


The only time removing the built-in bypass valve, and use a filter with a bypass valve is going to help, is if the filter is pretty free flowing and has a relatively high bypass valve setting. The goal is to prevent as many bypass events as possible. Keeping the engine RPM low until the oil warms up really helps reach that goal, and keeping the oil filter changed (clean) on a regular basis is the other factor.

Using that block bypass plug without using a filter with a bypass valve is a recipe for disaster.

The other aftermarket part - the block "barbell" - just seals the block cross-over passage better than the OEM barbell.
 
OK 2 filters fit the oem requirement one have the BP valve set at 22 the oem at 8. They both use different filter media I would think ( Fram TG versus FL500S )

Am I going to get a better filtration with the higher BP setting since the OP will push oil through the media up to a higher press. before the bp valve open ?
 
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