The rule for this already exist.

It must be an OEM equivilant sp. ie same weight and size.

Guys lets not get to worry about all this.

Engine nut/bolt hardware that is design as factory replacments are a non-issue. Things like head studs and rod bolts have the potential to be perceievd as performance enhancements.

Now if we really cannot get stock rod bolts or stock head studs then for these parts aftermarket is our only option. I have not had the time really know we can get these stock or not. Frankly I have never needed them in 10 years of track and race on my 944. Even with the rebuilds. I never considered replacing these. Of that could be why we can't get them. Now I can see a particuar stud/bolt being damaged. It can happen and junk a block or rod for that makes no sense. Now we can argue about how they fit under the aftermarket allowance rule, but it is my feeling that if OEM stock is NLA (no longer avaliable) and used just dones not make sense like for these items then we have no choice, but to allow the aftermarket part.

In the end it probably makes the most sense to write it into the rules to be clear. I don't like the idea of guys removing perfectly good stock hardware to replace it with ARP stuff because they will be wasting time and money. So to be 100% certain on this let me ask and get an answer for 1 question.

Are OEM ROD BOLTS and HEAD STUDS no longer avalialble (NLA)?

joepaluch wrote:


That is the question I am trying to get an answer to as well. Currently, none of the places I have looked have them (I cant find a part number either, but that could just be my ignorance). That doesn't mean they are NLA, but it is a strong possibility. Since I am new to these motors, that is why I asked the question in the first place, I just couldn't find the OEM bolts.

Joe, I agree with you completely. In fact, I was given the choice of ARP but told that it wasn't necessary at our engine speeds. Honestly, it never occurred to me that it might be a rule violation. Luckily I went with stock so it is a moot point.

If ARP/Racewear bolts are allowed specifically, you could add a note that it is purely for obsolescence and not considered necessary for reliability. Not that it will necessarily stop people from wasting money...

Since the rod nut is a 928 part number, I did some more searching in the 928 section of rennlist.

Here is what I found (emphasis mine):
"I tried sourcing new bolts for my 5.0L rods, but they're not avail. directly from Porsche. There maybe a different source that I don't know of. But, this is what I learned about the stock bolts. Apparently, Porsche designed the bolts to not yield when torqued properly, the nut is the one that crushes slightly."

"If your really into getting new bolts, then ARP makes a matching bolt/nut set for the 944 rods (which are exact fit for the S4 5.0L rod). But, they are heavier and have a higher clamping force, which will distort the rod large end. So you'll have to resize your big end to make them work properly."

So basically, it looks like if you need a new rod bolt (damaged, out of spec, over torqued etc) you have to go with aftermarket.