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Wildthings
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Joined: March 13, 2005
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 Posted: Wed Mar 20, 2019 9:51 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| Abscate wrote: |
93% of engine wear comes from start up, up from the 90% studied by SAE in 1960 using radioactive piston rings
If we charged a penny for each time this thread gets regurgitated we could payoff the national debt |
Do you have a link to this? |
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udidwht
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| Posted: Wed Mar 20, 2019 6:36 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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I only use Mobil 1 Extended Performance filter. If that is not available...
NAPA Gold or WIX
That isn't very often.
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raygreenwood
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| Posted: Thu Mar 21, 2019 7:25 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| Wildthings wrote: |
| raygreenwood wrote: |
| one thing that both Wix and Mann do....and they both advertize this.....is specific bypass spring pressures per part number....not just some generic spring used on all filters. On the fioters I opened....that had anti-drainback flap valves.....they were all fine. |
Since the Type 4 engine has a built in filter bypass valve I don't think there is a spec for a valve in the filter, and IIRC the factory recommended filters 40-50 years ago didn't even have bypass valves in them. Another point is that even if there was a bypass opening spec way back when, it might not be all that relevant today, as these engines were originally specced to run straight weight oil and today may well be running a 0w40 or 5w30, so the pressure drop of the cold oil across the filter is apt to have changed markedly over the years. |
Yes.....there are specs for the valves in the filters.....but they are not VW specs for our engines (as you noted).
The filter manufacturers have specs. Technically.....these filters....whichever manufacturer and whichever part number.....are not unique to our engines. This filter part number was around before VW chose it.
What I was getting at is that filters made by better manufacturers are made to a specification. There are specs for every part of the filter.There is a blueprint on file at the manufacturer somewhere.....you can bet on that.
From advertising and documents over the years.....Wix and Mann are about the only two that make note of the fact that they have specs for valve pressure and other parts. You dont hear zip out of the others.
Ray |
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Wildthings
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| Posted: Thu Mar 21, 2019 7:57 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| raygreenwood wrote: |
From advertising and documents over the years.....Wix and Mann are about the only two that make note of the fact that they have specs for valve pressure and other parts. You dont hear zip out of the others.
Ray |
I have never had much trouble getting filter specs over the years. Whether it be Hastings, Wix, Fram, or other. One might have problems getting specs for an OE filter such as Subaru or BMW, but not for aftermarket filters in my experience. I don't think automotive engineers always spend a lot of time figuring out what bypass pressure is best either. The needs of say my Toyota "F" engine and my Dodge 318 couldn't be much different yet the same filter is specced for both. The "F" engine only has bypass filtration, while the 318 has full flow so the amount of oil flowing through them is markedly different and I would think that running the same oil the 318 engine would open the bypass at a temperature 30-40° F higher than the "F" engine. |
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raygreenwood
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Location: Oklahoma City
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| Posted: Thu Mar 21, 2019 11:13 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| Wildthings wrote: |
| raygreenwood wrote: |
From advertising and documents over the years.....Wix and Mann are about the only two that make note of the fact that they have specs for valve pressure and other parts. You dont hear zip out of the others.
Ray |
I have never had much trouble getting filter specs over the years. Whether it be Hastings, Wix, Fram, or other. One might have problems getting specs for an OE filter such as Subaru or BMW, but not for aftermarket filters in my experience. I don't think automotive engineers always spend a lot of time figuring out what bypass pressure is best either. The needs of say my Toyota "F" engine and my Dodge 318 couldn't be much different yet the same filter is specced for both. The "F" engine only has bypass filtration, while the 318 has full flow so the amount of oil flowing through them is markedly different and I would think that running the same oil the 318 engine would open the bypass at a temperature 30-40° F higher than the "F" engine. |
Yes....they do spend time finding out about bypass pressures. Maybe not all manufacturers....but some do.
This was HUGE class action with VW that I know of....regarding starvation of camshaft bearings in mk1 and some mk2 watercooled engines. It was dead on caused by bypassing of pressure to the case by the oil filter......about 95% of it was traced to non VW installed aftermarket filters with weak and or improper bypass pressure.
Many people think that big scandal was about lack of anti drain back valve. That was PART of it. While that caused noisey start up and aeration in the oil.....it was not the cause of failure. The failure was improper bypass valve.
VW...was extremely specific about what oil filters to use. But.....what killed them is the fact that they were not 100% specific to all of the dealers. There were a fair amount of dealers installing the wrong filters in discount, under warranty oil changes.
This issue.....was the impetus behind installing that damned differential oil pressure warning system. It used no less than 3 oil pressure senders....OR two and a dual pole VDO sending unit if your car had a gauge.
What I was getting at....is that Mann for starters as the prime OEM supplier at that point and time and since....and Wix has stated this as well in literature......pays close attention to bypass valve pressures. They have a spec and stick to it....they say.
Whether your car mfg needs a specific pressure spec or even cares.....is not the issue. Howdver for those manufavturers that do require a specific spec.....they can go to the manufacturer and probably pull a current part number off the shelf that meets whatever spec they require.
And Mann and several other oil filter mfgs....were called onto the carpet back during this debacle....specifically about pressure specs....because some of the blame was about to be pinned on filter mfgs.
There were many thousands of mk 1 and mk2 engines that died this way. It was a big deal.
Ray |
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SGKent 
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| Posted: Thu Mar 21, 2019 12:02 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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Ray - are there any studies on which filter media sizes bypass the most? meaning that as the particulate size captured gets smaller the oil filter has a tendency to open the bypass more such that say 20% of the oil is being filtered and 80% is bypassing. On a filter that is designed to capture larger particulate then the bypass might be flowing the opposite - 20% bypassing and 80% filtering. Adding more pleats / surface area helps bypass less but if the media is too dense it will bypass easier. Do you know if there are any defined studies on this?
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Wildthings
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| Posted: Thu Mar 21, 2019 12:37 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| raygreenwood wrote: |
| Wildthings wrote: |
| raygreenwood wrote: |
From advertising and documents over the years.....Wix and Mann are about the only two that make note of the fact that they have specs for valve pressure and other parts. You dont hear zip out of the others.
Ray |
I have never had much trouble getting filter specs over the years. Whether it be Hastings, Wix, Fram, or other. One might have problems getting specs for an OE filter such as Subaru or BMW, but not for aftermarket filters in my experience. I don't think automotive engineers always spend a lot of time figuring out what bypass pressure is best either. The needs of say my Toyota "F" engine and my Dodge 318 couldn't be much different yet the same filter is specced for both. The "F" engine only has bypass filtration, while the 318 has full flow so the amount of oil flowing through them is markedly different and I would think that running the same oil the 318 engine would open the bypass at a temperature 30-40° F higher than the "F" engine. |
Yes....they do spend time finding out about bypass pressures. Maybe not all manufacturers....but some do.
This was HUGE class action with VW that I know of....regarding starvation of camshaft bearings in mk1 and some mk2 watercooled engines. It was dead on caused by bypassing of pressure to the case by the oil filter......about 95% of it was traced to non VW installed aftermarket filters with weak and or improper bypass pressure.
Many people think that big scandal was about lack of anti drain back valve. That was PART of it. While that caused noisey start up and aeration in the oil.....it was not the cause of failure. The failure was improper bypass valve.
VW...was extremely specific about what oil filters to use. But.....what killed them is the fact that they were not 100% specific to all of the dealers. There were a fair amount of dealers installing the wrong filters in discount, under warranty oil changes.
This issue.....was the impetus behind installing that damned differential oil pressure warning system. It used no less than 3 oil pressure senders....OR two and a dual pole VDO sending unit if your car had a gauge.
What I was getting at....is that Mann for starters as the prime OEM supplier at that point and time and since....and Wix has stated this as well in literature......pays close attention to bypass valve pressures. They have a spec and stick to it....they say.
Whether your car mfg needs a specific pressure spec or even cares.....is not the issue. Howdver for those manufavturers that do require a specific spec.....they can go to the manufacturer and probably pull a current part number off the shelf that meets whatever spec they require.
And Mann and several other oil filter mfgs....were called onto the carpet back during this debacle....specifically about pressure specs....because some of the blame was about to be pinned on filter mfgs.
There were many thousands of mk 1 and mk2 engines that died this way. It was a big deal.
Ray |
For starters, Type 4 engines don't need a bypass style filter as the bypass is designed into the filter head. My remembrance is that the spec filters when these engines were being made did not have a bypass setup, but I sure wouldn't want to swear to it. I do have a zero hour factory T-127 that I could remove the filter from and see if it has a bypass setup, but can't say what year the engine was made, but likely late in the aircooled era.
Also note than on a Type 4 engine the filter is between the pump and the first relieve valve so all the oil that the pump puts out is going to make it through the filter one way or another and then make it to the the drillings feeding the relief valve.
I have never seen a spin on filter that can somehow dump oil to the sump so that info is incorrect. Though it could be that if the bypass pressure was too high it could cause the main pressure relief to direct oil to the sump. Personally I would suspect that if what you say is true the VW engineers did not actually pay attention to the bypass pressure of the filter they were recommending and just grabbed one off the shelf that seemed handy. If VW did spec a bypass pressure and the aftermarket filter makers specced an interchange filter that didn't meet the spec, they would have been the ones at fault and not VW, so something is fishy here. |
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Abscate
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| Posted: Thu Mar 21, 2019 1:33 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| Wildthings wrote: |
| Abscate wrote: |
93% of engine wear comes from start up, up from the 90% studied by SAE in 1960 using radioactive piston rings
If we charged a penny for each time this thread gets regurgitated we could payoff the national debt |
Do you have a link to this? |
https://www.sae.org/publications/technical-papers/content/620506/
(I made up the 93% part)
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raygreenwood
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Location: Oklahoma City
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| Posted: Thu Mar 21, 2019 1:53 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| Wildthings wrote: |
| raygreenwood wrote: |
| Wildthings wrote: |
| raygreenwood wrote: |
From advertising and documents over the years.....Wix and Mann are about the only two that make note of the fact that they have specs for valve pressure and other parts. You dont hear zip out of the others.
Ray |
I have never had much trouble getting filter specs over the years. Whether it be Hastings, Wix, Fram, or other. One might have problems getting specs for an OE filter such as Subaru or BMW, but not for aftermarket filters in my experience. I don't think automotive engineers always spend a lot of time figuring out what bypass pressure is best either. The needs of say my Toyota "F" engine and my Dodge 318 couldn't be much different yet the same filter is specced for both. The "F" engine only has bypass filtration, while the 318 has full flow so the amount of oil flowing through them is markedly different and I would think that running the same oil the 318 engine would open the bypass at a temperature 30-40° F higher than the "F" engine. |
Yes....they do spend time finding out about bypass pressures. Maybe not all manufacturers....but some do.
This was HUGE class action with VW that I know of....regarding starvation of camshaft bearings in mk1 and some mk2 watercooled engines. It was dead on caused by bypassing of pressure to the case by the oil filter......about 95% of it was traced to non VW installed aftermarket filters with weak and or improper bypass pressure.
Many people think that big scandal was about lack of anti drain back valve. That was PART of it. While that caused noisey start up and aeration in the oil.....it was not the cause of failure. The failure was improper bypass valve.
VW...was extremely specific about what oil filters to use. But.....what killed them is the fact that they were not 100% specific to all of the dealers. There were a fair amount of dealers installing the wrong filters in discount, under warranty oil changes.
This issue.....was the impetus behind installing that damned differential oil pressure warning system. It used no less than 3 oil pressure senders....OR two and a dual pole VDO sending unit if your car had a gauge.
What I was getting at....is that Mann for starters as the prime OEM supplier at that point and time and since....and Wix has stated this as well in literature......pays close attention to bypass valve pressures. They have a spec and stick to it....they say.
Whether your car mfg needs a specific pressure spec or even cares.....is not the issue. Howdver for those manufavturers that do require a specific spec.....they can go to the manufacturer and probably pull a current part number off the shelf that meets whatever spec they require.
And Mann and several other oil filter mfgs....were called onto the carpet back during this debacle....specifically about pressure specs....because some of the blame was about to be pinned on filter mfgs.
There were many thousands of mk 1 and mk2 engines that died this way. It was a big deal.
Ray |
For starters, Type 4 engines don't need a bypass style filter as the bypass is designed into the filter head. My remembrance is that the spec filters when these engines were being made did not have a bypass setup, but I sure wouldn't want to swear to it. I do have a zero hour factory T-127 that I could remove the filter from and see if it has a bypass setup, but can't say what year the engine was made, but likely late in the aircooled era.
Also note than on a Type 4 engine the filter is between the pump and the first relieve valve so all the oil that the pump puts out is going to make it through the filter one way or another and then make it to the the drillings feeding the relief valve.
I have never seen a spin on filter that can somehow dump oil to the sump so that info is incorrect. Though it could be that if the bypass pressure was too high it could cause the main pressure relief to direct oil to the sump. Personally I would suspect that if what you say is true the VW engineers did not actually pay attention to the bypass pressure of the filter they were recommending and just grabbed one off the shelf that seemed handy. If VW did spec a bypass pressure and the aftermarket filter makers specced an interchange filter that didn't meet the spec, they would have been the ones at fault and not VW, so something is fishy here. |
Exactly...VW was at fault ....as I noted....which is why there was a class action lawsuit.
And...from what I can remember when this hit the news....its not that no one was making a filter to VW's spec....its obvious that VW had a spec they needed to meet....and looked for a filter that was already being made....that met that spec....and used that filter. Like everything else....they simply stated..."use our filter or the filter we spec or there will be trouble"....and there was.
To be clear....the REAL problem with the Mk-1 and Mk-2 debacle I was pointing out as an example...was a design issue in the engine that the improper oil filter help to exploit to destroy engines.
It kind of took a page out of the VW aircooled play book. On our engines....high oil pressure with cold oil is vented to the case right before the oil cooler to keep from damaging the cooler...right?
Same issue on the mk-1 rabbit...which used this kind of cool oil cooler.
This is a sandwich plate oil cooler. It goes between the oil filter head on the engine block...and the oil filter. It has coolant pipes that hook up to the water pump system.
The issue was that the oil galley that fed the camshaft bearings and lifters....was taken at the exit of the filter head so it only used direct filtered and cooled oil . The way the filter head was designed....when the filter dumped...it went to the sump and reduced the oil pressure to the cylinder head by something like 65-70% when hot. So in this case...the back pressure valve of the filter was critical to making a bad oil filter head design work normally.
Actually ....they....VW...in the case of the water cooled rabbit engine.... used a filter that worked perfectly for their system...and specified only that filter.
Whether a type 4 ...or any car....needs a bypass or not...is not the original point I was making.
The idea that the aftermarket filters....that physically "FIT" your engine....are being made to any kind of spec...is the exact issue I was getting at.
Bear in mind that the filter that came from the factory on the type 4....was never made with a VW in mind or any other vehicle (that I know of). Its simply a filter of a certain class and size used on hundreds of vehicles. However that does not mean it has no specifications.
The point I was making IS...that several OEM/aftermarket manufacturers...regardless of who needs any particular spec....pay closer attention to the details of how their filters are built. They consistently make them to a specified spec....their own internal spec.... Whether you need that spec or not....is not their issue.
The fact that whatever the spec is...is actually being held....means a far better and more consistent filter than a company that makes a filter that is made anywhere in the world with whatever springs or gaskets or media they have on hand...regardless of spec.
Mann and Wix...consistently work toward making parts to specific tolerances.
This is a little dry...and is obviously a Mann advertisement...but they get into the back pressure valve around 8.5 minutes into it. Its not a bad illustration of the differences you can find.
https://www.youtube.com/watch?v=rKwmk1RYHpk&t=744s
Ray[/quote] |
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Wildthings
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| Posted: Thu Mar 21, 2019 3:08 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| Quote: |
| Whether a type 4 ...or any car....needs a bypass or not...is not the original point I was making. |
Since this thread is specifically about Type 4 engines then it is important to note that your long essay on bypass valves has little or no application to Type 4 engines.
| Quote: |
| The way the filter head was designed....when the filter dumped...it went to the sump and reduced the oil pressure to the cylinder head by something like 65-70% when hot. So in this case...the back pressure valve of the filter was critical to making a bad oil filter head design work normally. |
Unless VW used some kind of really weird filter which I have never seen, it has one inlet and one outlet and can't dump oil anywhere. When in the bypass mode the oil goes out through exactly the same passage way as it does when the filter is not in the bypass mode. There may be a problem with the particular engines you are referring to, but it is not caused by the filter dumping oil anywhere and it doesn't apply in any way to a Type 4 engine.
From this drawing it looks like the oil pressure relief valve for at least some VW inline engine is in the oil pump, which would mean the wrong bypass valve setting could cause oil from the pump to be dumped prior to the filter in certain conditions. The drawing also shows a bypass valve built into the filter head. Maybe this bypass valve was added to solve the problem you are talking about, but it still doesn't apply in any way to a Type 4 engine as the oil pressure relief valve is plumbed differently on the Type 4 preventing this particular problem from ever happening.
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timvw7476
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| Posted: Thu Mar 21, 2019 6:18 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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The Mk 1 & Mk 2 engines can lose prime at the pump if you look at them wrong.
(Meaning oil change when oil is still too hot, say five-ten minutes after running.)
that would explain starved bearings/toasted engines...... |
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Wildthings
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| Posted: Thu Mar 21, 2019 7:14 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| timvw7476 wrote: |
The Mk 1 & Mk 2 engines can lose prime at the pump if you look at them wrong.
(Meaning oil change when oil is still too hot, say five-ten minutes after running.)
that would explain starved bearings/toasted engines...... |
That is one of the reasons I advocate for quick oil changes. Let the oil drain until the stream diminishes to a drip and then get the plug back in and fill her up. Prefilling the oil filter can also cause an air lock in the pump and lines that might actually delay the oil pressure coming up, this of course varies considerable from engine to engine.
As far as warming the engine up before you drain the oil, I don't want the oil to be hot enough to potentially burn my hands and arms, so a mile or so of driving after a cold start or five to ten minutes of idling is enough warmup in my book. |
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TomWesty
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| Posted: Thu Mar 21, 2019 9:05 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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For no particular technical reason I say WIX. 
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raygreenwood
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| Posted: Fri Mar 22, 2019 6:32 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| Wildthings wrote: |
| Quote: |
| Whether a type 4 ...or any car....needs a bypass or not...is not the original point I was making. |
Since this thread is specifically about Type 4 engines then it is important to note that your long essay on bypass valves has little or no application to Type 4 engines.
| Quote: |
| The way the filter head was designed....when the filter dumped...it went to the sump and reduced the oil pressure to the cylinder head by something like 65-70% when hot. So in this case...the back pressure valve of the filter was critical to making a bad oil filter head design work normally. |
Unless VW used some kind of really weird filter which I have never seen, it has one inlet and one outlet and can't dump oil anywhere. When in the bypass mode the oil goes out through exactly the same passage way as it does when the filter is not in the bypass mode. There may be a problem with the particular engines you are referring to, but it is not caused by the filter dumping oil anywhere and it doesn't apply in any way to a Type 4 engine.
From this drawing it looks like the oil pressure relief valve for at least some VW inline engine is in the oil pump, which would mean the wrong bypass valve setting could cause oil from the pump to be dumped prior to the filter in certain conditions. The drawing also shows a bypass valve built into the filter head. Maybe this bypass valve was added to solve the problem you are talking about, but it still doesn't apply in any way to a Type 4 engine as the oil pressure relief valve is plumbed differently on the Type 4 preventing this particular problem from ever happening.
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And....as per my EXACT point....it makes no difference what kind of engine we are talking about.
And....its even more important that YOU understand....since you have totally missed the POINT for the 4th set of posts in a row.........it has absolutely nothing to do with the bypass valve....or whether its about type 4....or whether you need a vqave or not........... 
I was simply pointing out the valve as an example....that those few filter companies that spend extra time and energy getting the small details like the bypass valve right.....MAKE BETTER QUALITY FILTERS ACROSS THE BOARD FOR ALL CARS!!!!
It has been YOU since line #1 of this whole thread section....that cant get that point and has been hung up in whether the valve is needed or not......jjjjjjeeeeeeeeezzzzzz
Ray |
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RalphWiggam
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| Posted: Fri Mar 22, 2019 6:39 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| TomWesty wrote: |
| For no particular technical reason I say WIX. |
I going to agree with you there. At lease until someone gets a chance to cut open a Mann W920/17 to see if there is a ADBV. |
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Wildthings
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| Posted: Fri Mar 22, 2019 7:17 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| raygreenwood wrote: |
It has been YOU since line #1 of this whole thread section....that cant get that point and has been hung up in whether the valve is needed or not......jjjjjjeeeeeeeeezzzzzz
Ray |
Ray, you never cease to amaze me on how much you can write about something that you seem to not comprehend at all. You obviously do not understand the operation of the lubrication system on either the T4 engine or the VW inline 4 cylinder engines and are unwilling to even try, yet your write on and on.
Just show me one spin-on filter design that is capable of dumping oil into the sump as you have repeatedly claimed happened on the Mk1 and Mk2 engines. |
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SGKent
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| Posted: Fri Mar 22, 2019 8:23 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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Mike - open up a late case, or simply read the supplement #17 VW released for the late GD cases. I've posted it here many times but I will post it again. The outlet from the single pressure relief goes into a passage back to the oil pump pickup. Prior to that the case dumped over pressure back to the sump.
Most oil filters have a bypass in them that allows over pressure to bypass the media. In case the filter lacks one, the oil filter bracket on a T-4 has a ball and spring in it that allows all the oil to bypass the filter if the pressure across the filter gets too high.
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Wildthings
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| Posted: Fri Mar 22, 2019 8:48 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| SGKent wrote: |
Mike - open up a late case, or simply read the supplement #17 VW released for the late GD cases. I've posted it here many times but I will post it again. The outlet from the single pressure relief goes into a passage back to the oil pump pickup. Prior to that the case dumped over pressure back to the sump.
Most oil filters have a bypass in them that allows over pressure to bypass the media. In case the filter lacks one, the oil filter bracket on a T-4 has a ball and spring in it that allows all the oil to bypass the filter if the pressure across the filter gets too high.
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What does that have to do with Ray's claim that the internal filter bypass dumps oil back into the sump? No one is saying that the pressure control valve (or whatever VW calls it) doesn't dump oil into the sump or wherever but neither an internal or external oil filter bypass does. The bypass valve BYPASSES the filter element, it never dumps oil back into the case ever, it would not be called a bypass valve if its function was something else.
This simple principle as shown in the drawings on Ratwell or the above one I posted for an inline engine just doesn't seem to be that hard to understand. As for a Type 4 and apparently for the later VW inline 4 engines having a bypass valve in the filter is not even necessary as the engineers added another bypass valve to their engines, either as part of the original design (for a Type 4) or a later improvement (for the inlines). |
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Amskeptic
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| Posted: Fri Mar 22, 2019 8:56 am Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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| RalphWiggam wrote: |
So you're saying that drainback is not an issue on the type4 engine?
That a drainback valve on the oil filter will not keep the galleys primed with oil when the engine is not running?
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An anti-drainback valve that actually works does help to keep the galleries from draining down between frequent starts. I don't think it helps if the engine has been sitting for weeks.
The bypass valve is a different thing. Some filters have an internal bypass if the media clogs, but the Type 4 engine preempts that either way with its own bypass valve located in the filter mount. This bypass valve is often briefly called into play on cold starts.
SG Kent, I read with interest your observations of foaming and sensitivity to losing oil because of the internal relief passage on later cases. I have had no weird behavior in any of my Type 4 engines since forever, except for a total loss of oil pressure in a hot engine that was tilted to the left on a dirt trail, in the Road Warrior's internal relief passage case. Scared the hell out of me.
I used Permatex Aviation around the relief passage during a subsequent rebuild, and never had a problem since. Any escape spot like:
oil pump-to-case
oil pick up tube-to-case
oil cooler
pressure switch
fuel pump push rod hole/sleeve-to-right lifter gallery
can allow oil to drain out of the galleries either before or after the pump.
If it is before the pump, you can get foaming or loss of pressure if low oil level and/or radically tilted engine..
If it is after the pump, you get delayed oil light out.
Colin
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SGKent
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Fri Mar 22, 2019 1:19 pm Post subject: Re: Wix vs Mann Oil Filters for Type4 |
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colin - it only happens if the bus sits a week or two.Think whatever you want but until someone comes up with a better idea it is cavitation. Letting it run a few seconds and turning it off, let it sit and start it again can cut 15 - 20 seconds off getting oil pressure on a late case. There is a audible change when the oil pressure comes up so I am sure that the gauge and sender are correct. There are a limited number of possible causes here for the late case syndrome.
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