Request - 3.6 through-case bolts ;) ARP gets $1K for theirs...

Apples to oranges. A diesel runs much cooler than a gas engine and the studs are mounted into cast iron.

We are talking about hotter EGT's with studs being mounted into dissimilar aluminum.

Nah. Take a duramax for example. Aluminum heads, max EGT 1450 deg (factory continuous rating of 1375, max boost 32psi), but has long exhaust studs. And can maintain high EGT's on long pulls for quite a long time. Rarely break.

Exhaust stud breakage isn't limited to Porsche's, it's an across the board problem. Sure, turbo cars made it worse. When I was working at a multi-car line dealership, it was everything that had short studs. The only thing that reliably fixed it was long studs. Spacers if using welded tubes and flanges, cast in spacers if using cast iron manifolds. I'm sure that somewhere in there is the cost. If it made it out of warranty, the factories didn't see it as a problem.

Just throwing it out there. If we're making a wish list of which hardware Neil should address next, exhaust studs should be high on the list.

Stainless Exhaust studs are also been remade with the same hex on the one end as the new head stud has. They come in two lengths for either exhaust flange thicknesses. Picture here are the original versions we have sold for years. The exhaust studs have gone through the same overall upgrade as the new head studs have. http://forums.pelicanparts.com/uploa...1569860747.jpg

CAD image of new Ex stud.http://forums.pelicanparts.com/uploa...1569861904.jpg

Thanks Neil!

" Cat and Cummins class 8 engines bolt up their exhaust manifolds with longer studs and a 1-2" spacer under the nut. And they rarely break. "

What I do.
http://forums.pelicanparts.com/uploa...1570451110.jpg

And, use nickel anti-seize, it has a higher temp rating than copper by a lot. Permatex copper is rated to 1800F, nickel to 2400F. Not sure where this copper rumor got started but I have read it several times and is simply not true, like a lot of stuff that you read these days. Also nickel on stainless is better than copper on stainless from a galvanic corrosion standpoint.

Nice studs. So with the collared case through bolts they act like a shuffle pin?

"""Nice studs. So with the collared case through bolts they act like a shuffle pin?""""[/QUOTE]

Exactly. But the installation requires some attention so the oil passage is not blocked.

An update on the new exhaust studs, we have decided to make these in Titanium as this material has superior heat control. The head side will be 8.00mm x 1.25 but the nut side will be 5/16"x 24 so we can use our Titanium nut and washer combo.

This material is used as an exhaust stud in many of our race engines that see continuous high RPM so we feel this is a good choice for this application. Common sense dictates installation, so will require the use of anti seize grease which we will provide and a torque value of 18 ft/lbs.

Any chance of using a metric fastener on the nut side? Staying consistent throughout the engine and vehicle may be a good choice. It is the path others chose in the same market place. If you are using SAE fasteners I would assume readily available, hence the choice? Unlikely "our titanium nut and washer combo" is produced just for you, given the volume. Metric fasteners in the same grade surely are available as well?

At any rate, I certainly tip my hat to the research and thought that goes into ensuring the product and materials function as well, or likely better, than intended. Which I am confident they do.

Cheers

You are correct why. It is about volume when making.

We use these nuts on many other engine applications and choosing the nut was about covering multiple uses.

Making 12pt Titanium nuts is expensive over steel as the process is done with heat and not cold. This requires more expense so we look how best to we can have our cake and eat as well.

I hate to do this, but anything we are about to produce in Titanium bolt and stud wise that requires a nut is coming with an SAE thread. Same reason. I'm looking function over thread size.

"""Also I'm in cahoots with your Snap On guy to sell more SAE sockets and wrenches."""

HA! I knew it! Throw some Whitworth size nuts in the mix, too!

And then we start using Lucas electrical systems!

Neil, I sent you an email about purchasing a set of these exhaust studs