Interesting note on case studs

euro911sc · euro911sc's Garage

I noticed today (maybe you all know this, but I did not) that when looking at the stud descriptions in PET or PP Catalog the length is measured from the surface to the end of the stud... NOT the entire stud length! for example: in the pic below (courtesy of Chris Bennet) the 32.5 mm studs listed on the bottom of the case will be described as 8mm x 32 and not 8mm x 48 which is the total length of the stud. The 32 is measured to include the long threaded portion plus the un-threaded portion of the stud, or so it seems...

euro911sc · euro911sc's Garage

forgot the damn pic again.... *slap head*

ChrisBennet · ChrisBennet's Garage

Some people never realize this so you aren't "the last one to know". I know a certain parts vendor (not PP) that doesn't know this and he's been in the new and used Porsche parts business longer than I can remember...
-Chris

304065 · 07-27-2007, 04:00 AM

What? Are you gentlemen saying that the stud spec is installed height, not overall length?

I'm not disagreeing but isn't that a very non-teutonic, non-DIN way to describe a part?

euro911sc · euro911sc's Garage

John,

Sorry to burst your bubble

I know you love having everything follow the rules and be exact

but yes that is exactly what we are saying. go pick up a stud that you know the part number of or measure an installed one and look in PET you will see... caused me several days of grief looking through the PET for studs that matched what I measured IN TOTAL LENGTH! I was loosing hair and I don't have that much left to begin with!!

-m

rw7810 · rw7810's Garage

Yes gentlemen, but doesn't it follow, since the length of a bolt doesn't include the head ......?

304065 · 07-27-2007, 07:29 AM

All right, I'm going to measure a few myself. I invite the rest of the global 911 community to do the same. Here's some 901 reference data. . .

euro911sc · euro911sc's Garage

Quote:

Originally Posted by rw7810

Yes gentlemen, but doesn't it follow, since the length of a bolt doesn't include the head ......?

Sure it follows... kinda... but a stud does not have a head

I guess if you take the side of the discussion that the length listed should reflect only the length of the fastener that is free for use fastening things and not its total length (as in bolt/screw descriptions)...

BUT, IMHO a stud is somewhat special... unless the threaded portion that is not part of the length listed is standardized you would end up with the same listing description for studs with entirely different overall lengths... It may very well be that there is some DIN stud standard out there that specs this out so we don't have this issue.

John:

The Dimension column... is that what you measured?? or from your book?

Best regards,

Michael

PS: Nowhere else but this board could we have such an arcane discussion and not be the laughing stock of the pub

speaking of pub... I need food

304065 · 07-27-2007, 08:20 AM

Michael,

Those are from the book. Obviously they change over the years.

I found a diagram for DIN 835, you gents are exactly right. The "L" dimension is the equivalent of grip length, or what you would measure under the head of a bolt. Fascinating.

euro911sc · euro911sc's Garage

Does Din 835 specify what the 'e' dimension should be?

best regards,

Michael

CruiseControl · 07-27-2007, 03:56 PM

Thanks John (the nuts and bolts reference man)
It is amazing what we all continue to learn from this forum.
A few months ago the local porsche dealership bought in a few studs from Germany for me. This explains why there were numerous attempts to get the correct required length.
Paul

euro911sc · euro911sc's Garage

Quote:

Originally Posted by CruiseControl

Thanks John (the nuts and bolts reference man)
It is amazing what we all continue to learn from this forum.
A few months ago the local porsche dealership bought in a few studs from Germany for me. This explains why there were numerous attempts to get the correct required length.
Paul

Yeah well its amazing how I just got my studs in from the father land and guess what.... yiup... wrong length. I needed a 78mm grip length and I got a 78 mm TOTAL length stud... 3 of them... and they aren't even cad plated!

What I wanted:
http://www.pelicanparts.com/cgi-bin/PartsLookup/search.cgi?command=show_page&Catalog_Name=911_USA_78_83_KATALOG&Illustration=101-10&Line_Item=12

the catalog says M8 x 78... the order on the packing slip has the correct part number/description... just wrong part. They must have picked up the wrong part as the other 10 studs I got were correct so even back at the factory they make errors...

Now I have to deal with the dealer

and it will be another 10 days before I get my case together... maybe more...

Best regards,

Michael

304065 · 07-31-2007, 08:16 AM

Looks like DIN 835 is a "tap end with interference fit" meaning the threads are sized bigger on the short end.

ChrisBennet · ChrisBennet's Garage

Quote:

Originally Posted by euro911sc

Yeah well its amazing how I just got my studs in from the father land and guess what.... yiup... wrong length. I needed a 78mm grip length and I got a 78 mm TOTAL length stud... 3 of them... and they aren't even cad plated!

What I wanted:
http://www.pelicanparts.com/cgi-bin/PartsLookup/search.cgi?command=show_page&Catalog_Name=911_USA_78_83_KATALOG&Illustration=101-10&Line_Item=12

the catalog says M8 x 78... the order on the packing slip has the correct part number/description... just wrong part. They must have picked up the wrong part as the other 10 studs I got were correct so even back at the factory they make errors...

Now I have to deal with the dealer

and it will be another 10 days before I get my case together... maybe more...

Best regards,

Michael

If the studs you got weren't "yellow" I suspect that they aren't really factory. Someone substituted an "equivalent" stud.
For example, if you order something from a dealer like Stoddard you won't necessary get factory parts.
-Chris

304065 · 07-31-2007, 10:16 AM

I agree with Chris. If they are black oxide, that's a DIN spec stud, but the factory would have specified yellow zinc for corrosion resistance in the aluminum case.

What stud remover are you guys using? I have a HAZET 10mm but I don't think it's intended to be used on the threaded portion of the stud, only the shank. At least when I used it to remove my headstuds it buggered the threads big time (no problem as they went in the garbage). But now when I contemplate R&Ring studs (such as the ones on my manifolds, see my other thread) I want something that won't damage them.

911SCfanatic · 911SCfanatic's Garage

Snap-On tool is the bomb for stud removal. I believe the p/n is referenced in Wayne's engine rebuilding book.

euro911sc · euro911sc's Garage

I'm using a Baum tool. This one is for 8mm and has a threaded collar w/ lock nut. I also have the cam style that you mention, John. It toasts threads in a second... DO NOT use it on your case studs unless you are replacing them all

At the time I tried to order the 10mm Baum as well, but the guy said they were out and stopped making them...

-Michael

911SCfanatic · 911SCfanatic's Garage

Look here:
http://buy1.snapon.com/catalog/item.asp?item_ID=10349&group_ID=1247
I just bought the 3 common thread pitches instead of the whole set. Very nice. Not German, but I think that's forgivable.

shbop · 07-31-2007, 08:01 PM

The Snap-On extractors are very nice, as are the installers. I bought a set of Matco extractors, a while back, in a pinch. They were reasonable, under $70 for a set of four, and worked quite well. They won't protect the threads the way the collets do, but worked quite well.

HKZ Bob · HKZ Bob's Garage

Euro911S You did great work, Thank you,
do you have this also for the timing chain bolts available.

Greetings Bob