Re: 1993 Quad4 GTZ: Project WTF
Posted: Tue Aug 07, 2018 4:03 am
More likely it is that the bolts are UNDER-torqued. Even if they were to OE specs, switching out to aluminum should have a different, and higher, torque-spec. Aluminum compresses differently than steel, of course, and is softer. Think about aluminum cylinder-heads, that frequently use torque-to-yield bolts to retain tension against them. Typically, bolts will get work-hardened and fatigue from insufficient torque causing vibrational impacts against them. I like the retaining-ring idea, I have something similar on the flywheel of my V-8 Indy, although that was more to hold a bushing to center the flywheel onto the hub -when this car was being built, no one was offering Northstar flywheels yet.GT_Indy wrote:The only things I can think of is the bolts might be over torqued and stretched, bolts might be bottomed out, the crank/flywheel isn't a true flat surface, or the bolts might not be good quality.
I've read about people getting an expert machine shop to machine the crank and flywheel with dowels to help relieve the bolts of the shear forces, that could be a possibility.
Being an aluminum flywheel I wonder if aluminum creep is happening (I know Aluminum can dent easily), where the metal deforms under the bolt heads and it becomes loose enough where the bolts can shear off. (Because the friction between the flywheel and crank gets reduced).
I wonder if he needs something like this made of strong steel to help clamp the aluminum flywheel to the crank:
Despite the performance enhancements, I would be hard-pressed to go aluminum for a flywheel. Even with my GTU, the F40 transmissions suffered more frequent issues, even complete failures, with lightweight flywheels, it puts more stress on the input shaft and softer synchronizers because it transmits more vibration and doesn't absorb the power-pulses from combustion as well. It just seems like a lot of reliability issues over these.