It warmed up enough today to go the the warehouse and try these out. I like the way they fit up and that the heads are 12mm. Factory nut are 13mm head. I was able to install them using a 12mm wobbel socket. The SS nut covers the entire flange of the SS heat exchangers.

they look great! will they get retightened/checked after they cool?

Engine is still on the stand. Waiting on the new heads from HAM.

They look stainless....are they ?
Is the washer part of the nut or a separate piece ?
Looks like the perfect solution.

Is there any locking feature built in?

--DD

Those are on a set of headers or he's? Mark shared those in my ex stud nut thread.

Looks good, are the studs standard or also stainless?

I used 316SS serrated M8 nuts from Amazon - haven't needed to retorque.

Amazon 316SS M8 nuts

Test studs are stock. Not sure what Len is going to use on the new heads he is building.

Nuts do have locking thread feature.

The test heat exchangers are SSI 2.0 L

Nut is all one piece. See original thread for comparison between stock and the SS one.

Be sure to use plenty of anti-seize whenever using a stainless nut on a stainless stud or bolt, especially in a heated application. Stainless is kind of "grabby" and the threads can permanently lock together (called "galling"). In this application that would just result in the stud coming out with the nut, so not a big deal other than your nut and stud becoming a bolt.

Update: BelMetric has stock size M8x56 stainless steel studs for $2.67 each. I ordered a set of 8 with shipping it came to $30. Going to send to HAM to install on the heads.

I think these nuts are titanium based on that other thread.

I'd be very concerned about galling of the threads, better hope you never have to remove those unless you went nuts with anti seize. Even if you did, I'd be a little worried.

^X2. Also, check and see if common stainless studs are strong enough to handle the thermal expansion and contraction, they're just a bit stronger than grade 2 hardware, which is why you never see stainless used for suspension parts.

Thermal properties are another consideration, will stainless nuts on stainless studs stay tight when heat cycled? Stainless transmits heat very poorly, which is why it warps so bad when it's welded (unless done properly by a knowledgeable welder) and why it burns up drill bits (the heat remains at the point of the drill bit and anneals its cutting edges). If you need a metal that acts as an insulator (such as heat shields), stainless is a great choice.

Couple of things here:

When you drill stainless you are work hardening the metal. That is why it burns out bits. Nothing to due with temperature. It has tondo with the steel's physical properties. Cutting speed and cutting head angle are critcal to not overwork the metal as it is being cut. What is happening is that the carbon grains are parcipitating out towards the edges of the grain bounderies. Diamonds are pure carbon and we all know how friggen hard those are.

When welding and due to the cyrstaline nature of metals is unique to the alloy. As the metal cools and depending on the rate of cooling this adds "induced" stress. Again depending on the alloy stainless has a tendency to stress and cool at different rates intergranulary which causes the warping. This can be relieved by uniformly heating or mechanicaly. Gotta be careful about mechanicaly relieving stainless.....see comment above...you can change its mechanical properties.

What I remember from my strength of materials stuff and from some experience. Ethan may know more he is the ME.

......oh yea....the other factoid thing I read....

The suspension thing why it.s not used:

Weight
Cost
Tendency to crevice crack .....the heating thing and work hardening thing.

Those be them...probably forgot a few others and not necessarily in that order.

Interesting. If that's the case, why does a coolant feed make it so much easier to drill or mill stainless? The coolant bath doesn't change the properties of either the drill or the steel. If you don't have a coolant feed, getting the cutting speed perfect makes a world of difference, assumed (as a DIY guy but not an engineer) it was because the chip ribbon was taking a lot of heat with it. Some drill geek material.

Dynamics is not my strength....there is a pun there.

To put it simply heat is a result of the process...so you aren.t adding heat to it. If the cutting speed is wrong it will create to much heat and if too much heat is created that carbide preciptation thing starts to happen. The coolant helps dissapate this and help cut it....running faster is better..... time is money.

To the OP.....should be fine using T 316 studs......but Len has a helluva lot more exoerience with type IV heads than me and machining. I build dams and bridges.