acorn nuts on sump plate

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Jim Goree
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acorn nuts on sump plate

#1 Post by Jim Goree »

Are the acorn (or cap nuts), as shown in attached picture,
20190126_112019.jpg
20190126_112019.jpg (3.58 MiB) Viewed 1567 times
standard on any 356 engine sump plate
 

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Jim Liberty
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Re: acorn nuts on sump plate

#2 Post by Jim Liberty »

They look very nice. The factory used a regular nut and alum. washer. I like the acorn nuts on my personal cars. ……………...Jim.
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Craig Richter
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Re: acorn nuts on sump plate

#3 Post by Craig Richter »

Because after you scrape on some LA pothole, unwinding the regular nut will pull the damaged stud out with it when you try to do proper maintenance and remove your sump plate!
 

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Vic Skirmants
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Re: acorn nuts on sump plate

#4 Post by Vic Skirmants »

Factory used a solid washer with a wave washer; no aluminum. Let's keep the history correct.

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Jim Liberty
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Re: acorn nuts on sump plate

#5 Post by Jim Liberty »

Thanks Vic. I remember alum. washers coming with the gasket kit for the sump plate. That said, I would not doubt any statement you make. Most of you know what an idiot I am. And, is not getting better with time.

…………………………….Jim.
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Martin Bruechle
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Re: acorn nuts on sump plate

#6 Post by Martin Bruechle »

The VW's had a aluminum acorn that was softer than the block so it would strip out before the case would.

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Alan Hall
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Re: acorn nuts on sump plate

#7 Post by Alan Hall »

An acorn nut with a copper washer was often used to prevent dripping oil from the studs.

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Dave Wildrick
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Re: acorn nuts on sump plate

#8 Post by Dave Wildrick »

Alan Hall wrote: Sun Feb 17, 2019 8:18 pm An acorn nut with a copper washer was often used to prevent dripping oil from the studs.
They look good but did not stop oil drips from studs on my cars. Permatex on the studs helped, but the only thing that worked well on both of my C coupes was those aftermarket thick aluminum sump plates (from Mainely by Design and now from Ron LaDow) that don't get indented by overtightening the nuts, as happens on the standard steel sump plates.
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Dick Weiss
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Re: acorn nuts on sump plate

#9 Post by Dick Weiss »

You should NOT use acorn nuts due to they may "bottom out" on the studs which need to extend 17-18mm for the OEM steel plate or the slightly longer studs
for the S90 "floating" intake plate assembly which was deleted during the early 60s due to warranty-replacements when the floating valve got stuck during cornering!
The same goes for the machined aluminum plate assembly, and I use a little wipe of non-hardening sealant on the gaskets if using the steel plate after it's been flattened.
If the studs come out of the case, I use Locktite to retain them, and if the threads are stipped, I use 7 x 6mm studs and adjust to the above exposure of the 6mm end(s).

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Mervyn Hyde
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Re: acorn nuts on sump plate

#10 Post by Mervyn Hyde »

Dick has a good point. When I removed the acorn nuts (I thought that these were original) to clean the mesh, magnet, etc., and replace the gaskets, I found that 3 of the studs stayed in the sump block. With some double nuts I removed those and cleaned out all the threads in the sump base, the nuts and the the studs themselves. Then refitted the acorn nuts on their studs and added a little Loctite green on remaining thread of the studs before refitting with brass washers. No leaks. Those nuts are a limitation to some extent however.
Merv
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Ron LaDow
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Re: acorn nuts on sump plate

#11 Post by Ron LaDow »

You can get oil leakage from bent plates and the studs. The bent plates are obvious, not so much the studs.
Most M/F machine threads are not 100% contact; there is some clearance designed and machined into them. As a result, the threads do not seal when fitted, the clearance forming a helical leak path along the length of the stud. And in fact pulling a nut tight on a stud can increase the leakage, so:
Threads.jpg
Threads.jpg (792.24 KiB) Viewed 1327 times
The same condition obtains inside the acorn nuts, so they are no more effective at stopping the leaks than a plain, old hex nuts.
The solution is assembly:
1. Remove all studs.
2. Thoroughly clean the female threads (Q-tip/pipe-cleaner and solvent) and the studs (soak in solvent), dry them.
3. Using thread locker (I like the mid-strength stuff), refit them to the proper depth and pre-load them in the direction used in service with a nut. (use a couple of loose washers to keep the locker from leaking down the threads into the nut)
4. Leave 'em overnight.
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DonCichocki
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Re: acorn nuts on sump plate

#12 Post by DonCichocki »

Nice presentation Ron!

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Wes Bender
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Re: acorn nuts on sump plate

#13 Post by Wes Bender »

Ron is a class act. Not once did he mention that he sells an excellent machined aluminum sump plate that also cures the pesky leaks. If he does mention his products (and he has a couple of times), he offers an apology first.

There are a couple of other vendors on the forum who constantly push their products or services under the pretext of offering advice and would probably benefit from following Ron's example. They know who they are and I suspect you all do too.
Some days it's just not worth chewing through the restraints.....

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Curt Dansby
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Re: acorn nuts on sump plate

#14 Post by Curt Dansby »

I can attest to Ron's presentation. I helps to let the car sit for some time to drip after removing the sump plate before doing your cleaning. You can clean the inside lip of the sump plate boss and spray out the holes with brake clean, but put a rag on the inside of the holes so you do not over spray and wash oil down from the upper levels of the engine.

I have had good luck with the green loctite also called sleeve retainer although this is not a medium grade that Ron prefers. Heat must be applied for removal. I also prefer the studs with the allen head end: available from vendors with knowledge in this particular area. :D

Curt

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C J Murray
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Re: acorn nuts on sump plate

#15 Post by C J Murray »

Why didn't Porsche use blind holes? I guess it never occurred to them that 4 quarts of oil was up there. It took them decades to provide blind holes where the tin screws to the top of the heads.
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