M6X12 Engine sheet metal screws?

[tom1394racing]

I have a bunch of these that I have saved over the years and had re-plated. There seem to be two different types. The photo below shows the Kamax and Boesner type with the integrated washer on the LHS. On the RHS is an example of the other type w/o the washer made by Graeka, Verbus, Karo and others. I have hundreds of the type w/o washer and many fewer of the washer type.

My reading of the PET only shows the type w/o washer and I do not remember where or when the washer type was used. Can anyone shed some light on this?.

[Robert5995]

Hi, Tom -

I don't believe the type with the captive washer is correct. As you said, the parts book shows separate washers for the tin. If you have lots of the bolts (not sheet metal screws) without the captive washer, let me know - I am building up my engine this winter and it would be cool to have correct tin hardware, thanks!

- Rob

[tom1394racing]

The M6X12 bolts with captive washers came from somewhere on early 911's. Anyone have an idea.

Rob...I do have plenty of the early bolts. Let me know what you need.

[gled49]

Tom, rob is right, captured washer bolts were later, like 3.2 or such. In your pix the 8.8 bolts are my favorite and I use them right or wrong. The washer don't collapse and have a slightly larger OD which protects the sheet metal. The one in the middle (10.9) are a cutting bolt with tri-fluted threads that you can see and feel. They are referred to as locking bolts in their description. The problem with them is they are hard on the threads in the ALU or MAG or weld nuts in the sheet metal as they are always cutting the threads. I used them on my race motors and screws wouldn't come out, but after lots of rebuilds you could see the abuse of the threads. The original bolts and small washers were replaced by the later ones because of the inadequacies of the originals. G

[Jon B]

The M6X12 bolts with captive washers came from somewhere on early 911's. Anyone have an idea.

Tom, hardware in the SWB era still had DIN grades, so in terms of originality these ISO grade screws are really 69> items.

Jon B.
Vista, CA

[tom1394racing]

I did some checking based on all the feedback you guys provided. I was fooled by the Kamax marking thinking they were early bolts. It turns out that the P/N is 999 075 039 02 and they were introduced in '78 for the SC.

Thanks for the education!

[Richy]

My '79SC did not have captive washers , but my '80 did .