Deciphering fastener specs from the parts catalogue

[Tremelune]

I'm doing some aftermarket-to-stock body panel swaps on my car, and I'm finding a fair number of off-the-shelf fasteners that were installed in the past. I'd like to replace them all en masse with fasteners consistent to what was on the car when it came from the factory. That said, I grow weary of paying Porsche a dollar for a common M6 bolt. I'm about to buy a hundred or so nuts, bolts, washers, etc, and I'm wondering if there is an alternative.

When I have the fastener in my hand, I can measure it and read markings. When I've never had the fastener, it becomes more difficult. Is there a good way to translate the German/Porsche descriptions in the parts catalog?

It's fairly easy to figure "hexagon-head bolt M 8 X 40" is a 40mm M8 bolt, likely an 8.8 or 10.9 zinc coated sucker with a 1.25mm thread pitch. What boggles me are these:

- tapping screw BZ 4,2 X 16
- speed nut B 4,2
- washer A 10,5
- lock ring B 8

I've found a few strange tags that show "B" and "A" are standard metric terms, but I haven't found a good explanation for the less common fasteners. Anyone know what these things mean?

Am I spinning too many wheels here to save a buck? Should I just punch in the part numbers and pay the price instead of risking using a standard nut and thread lock instead of a prevailing torque lock nut?? I'm not taking risks with critical components, I'm just tired of punching in part numbers when I could just buy a giant sack of washers...

[Harpo]

I can help with some of this

I'm not aware of any Porsche suspension bolts that are 10.9. Most M8 are 1.25 pitch. Tapping screw is a M4.2x16. same with the speed nut

David

[javadog]

"tapping screw BZ 4,2 X 16" ... that's going to be a sheet metal screw. The 4.2 is the nominal diameter in mm but you'll find it's just the metric equivalent to a regular US sheet metal screw. The 16 denotes the length.

The speed nut is the sheet metal nut (or Tinnerman nut) for that size of sheet metal screw.

The "washer A 10,5" is a washer with a 10.5mm ID that is meant for a 10mm bolt.

Etc.

Some of these things may have slight variations ( head design, etc.) so you can sometimes just Google the Porsche part number to see what it looks like.

These were mostly yellow cad originally, so get yellow zinc if you want to mimic the look. Pelican used to offer hardware assortments, you might consider some of those.

JR

[chris_seven]

In metric trems there are 3 types of washers.

Form A, Form B and Form C

M5 washers will all have the smae ID but the 'Form' denotes the OD and the thickness.

Trailing Arm Bolts are normally Grade 10.9 and I think that the bolts that hold the tporsion bar covers are also Grade 10.9.

[Trackrash]

Are you wanting to go full concourse? With fasteners like I have in my hand? Or are you just making sure you have the correct strength fastener? The workshop manual will state the size and strength of the bolts. BTW, FWIW my car has 8.8Ks on the torsion covers and 10Ks mounting the front brake calipers. I can't believe there isn't a thread on correct fasteners for 911s.

[Tremelune]

This is all very helpful.

I'm not too concerned with concours/originality, I'm mainly just trying to find a way to source fresh suckers to replace the ones I pull off the car without having to go through Porsche's 10x markup. I used to just hit them with a wire brush and reinstall them, but that scrapes off the zinc coating and they rust pretty quickly after.

I have a Bentley that doesn't specify too much, and I've had a hard time finding a real factory manual that isn't some weird copy being sold on eBay. I'm surprised there isn't a compiled reference for every standard fastener on every one of these cars, but now that I'm sitting here cataloging one for just the front bodywork of just my car...it is tedious at best.

Corroboration of washer forms:

https://www.fastenright.com/general-fixings/washers-forms-a-b-c-d/wsr29

[Tremelune]

Numerous metric DIN specs:

Specifications Free Downloads | The Fastener Resource Center

[Trackrash]

On my just finished motor, I got a lot of the miscellaneous fasteners and small bolts and nuts I needed from Ace. The Ace near me has an amazing assortment. Problem is, they are white zinc.

The yellow zinc is hard to find. I bought the yellow chromate solution from Caswell to color mine. Maybe you saw the thread. DIY Yellow Cadmium Plating - works amazing!

The 6mm and 8mm yellow nyloc nuts are available here on Pelican, very reasonable.

What I could not find are the sheet metal screws like what Porsche used to use on the front fenders.

Edit: this picture looks a lot better on my computer. I'm not sure what Pelican wants for a large clear photo.

[Tremelune]

This has been educational, but perhaps not in the way I expected. In the end, the gains for sourcing standard fasteners are small, since there are very few duplicates on the car. I bought boxes of washers and nuts, which saved a buck and likely some hassle, but the time I spent researching these fasteners was way more than their cost justifies...unless you enjoy that kind of thing!

For the most part, it was more effective to just go down the list, paste the numbers into Pelican's search, and pay the price...I researched every single fastener for my front end project and came up with a surprising number of bits that were plastic, a non-standard size, or otherwise cheap to purchase as a Genuine Porsche Part.

Good times.

[Trackrash]

Ok, so now you owe us some pictures when your order arrives.

Amazing that you can still get everything for these cars!

[Shaun @ Tru6]

Originally Posted by Trackrash

Are you wanting to go full concourse? With fasteners like I have in my hand? Or are you just making sure you have the correct strength fastener? The workshop manual will state the size and strength of the bolts. BTW, FWIW my car has 8.8Ks on the torsion covers and 10Ks mounting the front brake calipers. I can't believe there isn't a thread on correct fasteners for 911s.

I have slowly been building a 911 hardware library that details bolt/cap screw application, quantity, head type, size, length, pitch, strength, associated nuts and washers, manufacturer and years used.

Ultimately the goal is help concours people put the right bolt in the right place for their year of car. While 99% of folks really could not care less, there are definitely some out there who wouldn't want to use a Kamax when a Dera was used in, say, a 69. It's not an exact science since Porsche just bought a ton of hardware and used it until it ran out and they got a better deal from another mfg. Below are all the manufacturers I have catalogued so far.

On the topic of replacement fasteners, Bel-metric is an amazing resource. https://www.belmetric.com/ I highly recommend them, small family run business, most of their hardware is German and they do everything at our level. Speaking of which, back when there was such a thing as a 911 parts car, I was simply dumbfounded on so many occasions what PO's used for replacement hardware, all garbage.

Tracking down a correct Graeka is rarely necessary but for the love of all that is good, please use high quality, correct type and style hardware when replacing worn, rusty hardware. And always use fresh Schnorr, lock and wave washers. Please be good stewards for these cars.

Karro
Verbus
Kamax
Dera
Lobo
Graeka
Nedur
F+H
3F
Dorn
Arbed
Omel
Ribe
Thiessen

[Shaun @ Tru6]

Originally Posted by javadog

"tapping screw BZ 4,2 X 16" ... that's going to be a sheet metal screw. The 4.2 is the nominal diameter in mm but you'll find it's just the metric equivalent to a regular US sheet metal screw. The 16 denotes the length.

The speed nut is the sheet metal nut (or Tinnerman nut) for that size of sheet metal screw.

The "washer A 10,5" is a washer with a 10.5mm ID that is meant for a 10mm bolt.

Etc.

Some of these things may have slight variations ( head design, etc.) so you can sometimes just Google the Porsche part number to see what it looks like.

These were mostly yellow cad originally, so get yellow zinc if you want to mimic the look. Pelican used to offer hardware assortments, you might consider some of those.

JR

Good information JR but Porsche didn't use yellow cadmium for any 911 hardware, it was all yellow zinc. There may have been some clear cadmium on early SWB cars but there is even debate about that.

[Tremelune]

Is there a way to identify the usage of a Schnorr lock washer without seeing it on the car? When I searched the Porsche part numbers, the image of every lock washer was the traditional split-ring design (for this particular project). Not to imply that random vendor product photos are an authority, of course.

Though the Schnorr are of a more effective design, there was a NASA study that dismissed the value of split-ring washers...I trust thread locker, but also use the washers anyway. Nord Lock washers seem comparable.

That document you're compiling sounds very useful, even for those willing to deviate from the "brand" of fastener. I'd love to see it in whatever form it's currently in...

[Shaun @ Tru6]

Off the top of my head, I think the only places Schnorr washers are used is under the hex socket bolts on the strut mounts and for the toe and camber eccentrics on the spring plates.

[Tremelune]

Originally Posted by Shaun @ Tru6

Off the top of my head, I think the only places Schnorr washers are used is under the hex socket bolts on the strut mounts and for the toe and camber eccentrics on the spring plates.

Another pretty damn good top-of-the head...The only reason I know what washers you're even talking about is because I took my spring plate eccentrics off last week!

[Tremelune]

Another random document about fasteners I found at the end of this thread about lock washers...

[tirwin]

I bought one of these metric fastener kits a few years ago when I was working on the car. It has a good assortment of the most common fasteners. This might be useful.

911/944 Yellow Zinc Fastener Kits

[Brian Cameron]

Originally Posted by Shaun @ Tru6

Off the top of my head, I think the only places Schnorr washers are used is under the hex socket bolts on the strut mounts and for the toe and camber eccentrics on the spring plates.

Suggest using on axle bolts also. Otherwise, think clutch cable / brake line / throttle linkage salad...

[Shaun @ Tru6]

Originally Posted by Brian Cameron

Suggest using on axle bolts also. Otherwise, think clutch cable / brake line / throttle linkage salad...

Agreed!

[tirwin]

Originally Posted by Brian Cameron

Suggest using on axle bolts also. Otherwise, think clutch cable / brake line / throttle linkage salad...

Agreed as well. If you have the original 'thick' flange axles then I like the Stage8 fasteners. They use a half moon washer and a retaining circlip to prevent back-out. I just tried to look up the part # but their website has changed and I can't find it now.

The bolt size and depth changed between the 'thick' and 'thin' flanges. If I remember correctly, Stage8 doesn't make a set that will work for the thin flange size -- unless something has changed they only make the size for the thick flange. If you have the thin flanges, the Schnorr washers are a great solution.