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[la_strega_nera]

Ben,Is that Canadian,Us,or window money your talking here?

Pacific Pesos (Australian Dollars).
I've got to call the supplier i've been getting stuff through lately on monday, so i'll price them up for you.

[Giulietta24vTT]

This just reminds me of another method I use to stop spinning studs and bolts(even though I didn't use it on my front brakes setup and went with the steel ring and tapped 12X1.5 holes+long HT bolts):

I drilled and tapped M5 through a bolt's head all the way to the surface area (in the picture shown is my turbo's split flange installed with head-cut bolts), this prevents the bolt from movinga nd allows easy removal of the bolt when needed(no need to tap the m12x1.5 since the small bolts lock the big ones tightly to the metal surface, I assume this can be adopted to the steel ring, disc itself or even on the hub assembly if one wants to mount the discs outboard.
note that for better balabce and clean surface one can use headless allen bolts:)

[Barry]

Chen,this is probably the one place you DONT want to lock the studs in....You are probably going to have to replace them often..I use a stainless stud..it does not sieze (or freeze as the yankees say...)

[Mats]

Stainless? I'd use regular studs from the OEM application, does stainless expand more or less with heat (never can remember that one)? If it exapnds less there will be a huge thermal expansion mismatch and possibly it will break something.

[Maurizio]

Stainless expands less, and have had relaxation problems with stainless bolts.
For this kind of an application nickel plated 12.9 bolts, they won't sieze either.

[Barry]

These are 10mm studs for gods sake....How are they going to break something?? Because they are stainless ????
Relaxation of what?? the bolts,the turbo flange?? never..and they DONT sieze!! Thats the good part of using stainless...forget expansion rates with these studs..they WORK!!!

[la_strega_nera]

These are 10mm studs for gods sake....How are they going to break something?? Because they are stainless ????
Relaxation of what?? the bolts,the turbo flange?? never..and they DONT sieze!! Thats the good part of using stainless...forget expansion rates with these studs..they WORK!!!

316 Stainless CTE= 18.5microm/m/degree celcius
1030 Steel CTE= 11.7
4140 steel CTE= 12.2-14.6 depending on temp range (higher rate at high temps)
Cast iron is about 12, so many different grades to choose from.

Expansion rates really are only a problem when you play with aluminium and steel, or similarly massively dissimilar metals.
Bolt seizures in high temp applications tend to more often associated with temperature driven surface corrosion between the materials, and this is where stainless bolts or brass nuts work really well

As for the bolt relaxation issue, because stainless bolts expand more, you now have less clamping force available at the bolt head/flange/nut, making it more likely that the bolt can be backed out, and this is most likely what you're seeing, rather than stretch.
Stretch can occur if clamping a high CTE material with a low CTE and are close to the yeild point of the bolt either to start with, or as the temperature goes up.

[Barry]

"As for the bolt relaxation issue, because stainless bolts expand more, you now have less clamping force available at the bolt head/flange/nut, making it more likely that the bolt can be backed out, and this is most likely what you're seeing, rather than stretch.
Stretch can occur if clamping a high CTE material with a low CTE and are close to the yeild point of the bolt either to start with, or as the temperature goes up."



Then I quickly whip out the ol 14mm modified spanner and tighten it more...........


Ever hear of the old farmer who sends his son to varsity couse he doesnt want him to be a poor farmer?
Kid gets home and dad asks"What have you learnt ,Son?
"2 pi are squared ,Dad"he says proudly..
The farmers whacks him across the forehead..
"No!"He says
"2 bread are square,2 pie are round!!!"



Well,Im the old farmer here....

[la_strega_nera]

Then I quickly whip out the ol 14mm modified spanner and tighten it more...........

Thats right, tighten it up till you feel the thread strip (or the bolt let go.... was using someone elses socket set with a longer handle ), and back it off half a turn

[Zamani]

Well Ben, at least Bazza won't have to use anti-seize using that method.

[Barry]

Ben,Go away.....Go hound the conrod blokes,Im not getting into a scrap with you...

Ill watch us beat you blokes at cricket instead..

[Giulietta24vTT]

Barry,
On my turbo flange there in no problem removing the studs,which are actually not studs but machined steel headless bolts.
I can easily remove the 5mm allen bolts and then remove the 10mm turbo "studs" by hand, using higher grade 5mm bolts prevents them from getting stuck in the flange, also this method keeps the studs from spinning both ways , sometimes studs getting pulled out when releasing the turbo , this can't happen here.

P.S -I have put the flange and manifold's parts in a stress release oven to avoid some welding's diformation ...

Back to Brakes again

[Jim K]

How about y'all take your stainless screwing somewhere else to play with??? This is a gd BRAKE thread!
Ok class, I did an experiment today (not that you give a ....) re. brakes: After installing the 310x32mm Ultralite 32-fin Wilwoods+alloy bells+4pots years ago, every time I hit the track the discs would warp after a couple of hard laps (summer or winter). A crappy condition, corrected only with subsequent on-car truing. Everything back to normal until the next time, same occurrence. Pretty soon the 32mm disc became 29mm, dangerously thin for the Ultralite type. I THEN thought about removing the stock splash guard (stone guard?) as I figured there must be great temp differential between the two disc faces. I decided that the ultimate (worst case) test, would be to hit the track with these thinned-down discs and see what would happen. The greatly reduced thermal capacity would tax the system and IF it didn't warp this time, the move was right (I have no other brake cooling arrangements like ducts, this being a street car). Well,they DIDN'T warp but after ~30 laps they developed the next best thing to warping: cracks! One of them ~20mm long and some smaller ones. (I'll try to post pics soon). I thought it prudent to quit and head home. Also, I had to pump the pedal 2-3 times and I suspect fluid boiling (RBF600 but its over a year old, pads being DS2500). Some other guys were bleeding their calipers after a few laps, but I didn't bother.
When warping was bugging me, I contacted Wilwood and was told Ultralites are the wrong choice for a 1400kg car on a heavy braking track and I should have the Heavy Duty 48-fin rotors, so I ordered and got them. Weight difference with the Ultralites is 1.5lbs (700gr)ea. Today's test proved I could have bought the Ultralites again, since the warping cause was definitely found. Maybe obvious to you guys, but I had to find out. BTW, between studs, ON-wheel temp got to 122*C today! All in all, a great perfect weather day (short sleeves Mats!! )
Jim K.

[Mats]

I suddenly lost all respect for you, splash guards???

You should have kept them though but make a hose flange on tem and force feed the insides with cold air.
The disks probably cracked because they were were too thin.

[Giulietta24vTT]

I suddenly lost all respect for you, splash guards???

You should have kept them though but make a hose flange on tem and force feed the insides with cold air.
The disks probably cracked because they were were too thin.

That's a great idea!