Oil screen, oil sump plate questions (mostly philosophical)

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JLT
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Location: Sacramento CA
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Oil screen, oil sump plate questions (mostly philosophical)

Post by JLT » Fri Feb 28, 2020 3:56 pm

I was replacing the oil sump gaskets and inspecting the oil screen on my 1600 DP, and the following questions occurred to me:

1. Now that I'm running an oil filter (and have been for the last 40k miles on this engine), is the oil screen still necessary? Every time I've pulled the screen on an engine equipped with an oil filter (and that's been the case on my last two buses), it's been totally spotless. I figure that the only thing I'd be concerned with is if I saw metal filings in it, signifying that the engine has repurposed itself as a machine shop, but all that would have been caught by the filter, right?

2. What's the deal now with those "acorn" nuts that retain the sump plate? Back when I was a sprout in the '70s, doing my first oil change, I went to the dealership and asked for one of those oil screen gasket kits, with the seven copper washers. The parts guy handed me the kit, along with six nuts. "I already have the nuts," I said. "Are they the acorn nuts?" he asked. I said "Yes."

"Throw 'em out," he said. "They're the cause of more busted studs than anything." He insisted that VW policy (at least at his dealership ... I didn't know whether the order came from VW itself) was to replace those nuts with conventional ones. So I bought the new nuts and used them on every engine I rebuilt. But now I have an engine built by one of the most reputable people around, and it has the acorn nuts. Was the parts guy bullshitting me? Or was there once something suspicious about those acorn nuts?
-- JLT
Sacramento CA

Present bus: '71 Dormobile Westie "George"
(sometimes towing a '65 Allstate single-wheel trailer)
Former buses: '61 17-window Deluxe "Pink Bus"
'70 Frankenwestie "Blunder Bus"
'71 Frankenwestie "Thunder Bus"

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asiab3
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Re: Oil screen, oil sump plate questions (mostly philosophical)

Post by asiab3 » Fri Feb 28, 2020 8:16 pm

I think the screen serves to protect the pump from large debris, maybe, but its real function is to provide an easy inspection for oil changers like us. After all, how would I have caught this piece of my piston ring last summer if I didn't clean the strainer? :)

Image


Most of our "inspection" is done by wiping the sump plate with a clean white paper towel. The oil between the strainer and sump plate does not circulate very much, and lots of goodies may be hiding down there, awaiting our investigations.

--

When the studs are protruding so far out that acorns grab the stud after bottoming out, the tension will usually pull the stud out with the nut at the next oil change. (Magnesium doesn't like repeated installations/removals.) They DO seal oil leaks on the threads better than any other nut, but with the cheap and thin gaskets we get nowadays, I'm finding more and more studs are coming out of T1 sumps.

I have heard old-timers talk about their hatred of the acorn nuts/pulled studs, but I've never heard a statement from a VW employee of the time period. I can tighten them to 5 ft*lbs. only by feel, or with a good quality torque wrench, so I don't really have any problems, but that's just my experience…

Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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JLT
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Re: Oil screen, oil sump plate questions (mostly philosophical)

Post by JLT » Sat Feb 29, 2020 11:14 am

asiab3 wrote:
Fri Feb 28, 2020 8:16 pm
I think the screen serves to protect the pump from large debris, maybe, but its real function is to provide an easy inspection for oil changers like us. After all, how would I have caught this piece of my piston ring last summer if I didn't clean the strainer? :)
Does your bus have an oil filter? If so, I'd think that it would have caught that fragment.
-- JLT
Sacramento CA

Present bus: '71 Dormobile Westie "George"
(sometimes towing a '65 Allstate single-wheel trailer)
Former buses: '61 17-window Deluxe "Pink Bus"
'70 Frankenwestie "Blunder Bus"
'71 Frankenwestie "Thunder Bus"

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asiab3
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Location: San Diego, CA
Contact:
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Re: Oil screen, oil sump plate questions (mostly philosophical)

Post by asiab3 » Sat Feb 29, 2020 6:25 pm

It doesn't have a filter; too complex for my minimalist lifestyle. :)

Without a strainer, my oil pump could have digested the ring shard… I assume the sudden blockage at the pump would snap the drive tang clean off the pump shaft and leave me without oil pressure. Maybe it could have passed through the pump and blocked oil flow, or even more exciting, could have been churned into bits!

Yes, then an oil filter would have caught it for sure. And I never would have caught the issue, and the engine would have cost me a few hundred dollars last year in oil consumption. Do I sound like The Samba yet? :geek:

I will install an oil filter in my Volkswagen as soon as I have an oil filtration issue. ;)

Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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