Do you mean Belleville constant torque washer stacks? Like are used on some wood props?
Marc
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lehanover@aol.com
Sent: Sunday, March 13, 2011 6:48 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Cracking exhaust manifolds/ Crankcase ventilation
On my home spun exhaust for my 3-rotor, I tighten the exhaust studs for the center rotor, but only snug down the bolts for #1 and #3 in order to allow the exhaust manifold to grow and shrink as necessary. With 1600-1700* EGT's, it seems obvious that the manifold will grow more than the engine and if not allowed to move, it will crack. By torquing them only enough to prevent leakage, they are allowed to grow as needed, preventing cracks. So far, no broken studs or cracked exhaust manifold on my 3-rotor.
How about you torque up the center most stud to auto spec, then use 2 bevel washers flange to flange pulled down just short of flat on all other studs.
Then use a short stack of bevel washers above and below a flange on the turbo setup to a strut to support the weight and keep the strain off of the manifold.