10x48 rocker stand bolts

[Alan Hall]

I need a few 10mm x 48mm bolts used to hold down the iron rocker strand bridge. Anyone know a source for these?
Thanks,
Alan

[David Jones]

Call Vic, he probably has a box full of them.

[Brad Ripley]

Originals of those bolts were DIN 70613 which is a normal bolt but with a smaller head -- in this case 14 across the flats. The spec in parts catalog is 10 x 45, not 48.

[Alan Hall]

Brad, The "A" parts book shows this bolt as a M10x48 DIN 931-8G. Based on your comment I checked the pre-A and the "B" parts books. The pre-A book does show a 10x45 DIN 70614-8G like you mentioned, but the "B" parts book shows the same M10x48 DIN 931-8G as in the "A" book. I have 2 of the 48mm bolts and would like to get 6 more for a couple of engines I am doing. I suppose I could use 45mm bolts, but suspect the factory had a reason for going to the 48mm length as it is not a standard length! Any help finding these would be appreciated.

[Brad Ripley]

In any event Porsche no longer has those bolts. Can DIN 931s be used?

[Vic Skirmants]

Early bolts were 17mm ATF, 1960 and later were 15mm, Brad.
I just sent a bunch of 15s to a friend; David, stop telling people to ask me for parts; I'm running out!
Alan: I have plenty of 17s; call me 810-688-2059

[David Jones]

OK Vic, I was just worried about you not having enough money for retirement. You could I suppose run out of parts before your expiry date.

[Doug McDonnell]

Thanks for the morning laugh David.

[Albert Tiedemann]

Alan:

The ATF dimensions given by Vic are correct. The reduced head ATF for the 10 mm cap screw was introduced with the use of the light alloy rocker arm mounting in 1960. The reason for using this cap screw was for clearance at the center stand mounting [more clearance for using socket wrench for installation]. There is also a companion wavy washer used with reduced outside diameter, and this reduced outside diameter is also more in proportional use with the reduced ATF dimension [17 down to 15]. The purpose of the reduced diameter wavy washer was to provide edge distance clearance with the center stand. If the standard 10 DIN 137B washer is used indiscriminately, there is real danger in producing a scallop in the base of the center mount. No access to books from my present location, but you may find that the washer at this location is a Porsche part number. My recollection is the outside diameter is 18 mm. Since these fasteners [both the washer and the cap screw are black oxide finish and in the oil environment] both can be whittled down to the correct proportions in diameter and ATF and the length of a 10x 50 DIN 931 can be reduced to 48 mm. without consequence. The 48 mm length is likely to avoid bottoming out in holes not tapped deeply enough in the cylinder head fasteners. Forward thinking, perhaps to manufacture in China.

[John Clarke]

Hi all,
Vic is running out , Calling Ron Ladow ! There's a market here Ron for the correct material and spec ?
Regards Jay

[Olivier Auvray]

You can use CV joint bolt from a 911.

It's a socket head screw, 12.9 class, fits perfectly, cheap............... but not original!

[Eric Wills]

I seem to have a few extra, but most all are 15mm ATF. I always figured the rocker arms and shafts were the first to go, so plenty of stands and hardware should be around.

The correct reduced OD diameter wave washers that Ab mentioned can be found here: https://www.belmetric.com/zinc-form-a-s ... 2ekcc017k7


EW