Quote:
Originally Posted by Clembo
Has anyone contacted the design engineers about the original analysis for the stock triangular bars? What, if any, were the original requirements for the stock triangle bar installation (preload, strut tower position, point at assembley, etc.)? And what were the fastening requirements? When I see mounting studs intentionally painted after fastener installation I assume there was a torque requirement. And does this torque stretch the mounting studs as it does in some cases? If so, these studs may require replacement before reusing them as attachment points. And depending on the new loading forces and directions, they may require resizing as well.
I'm not questioning your present analysis or data, only that without knowing the original parameters, you may be unintentionally altering some of the original design assumptions and/or criterior. I see people yanking parts off their cars all the time (and often replacing them with something else) with little thought as to how or why they were put there in the first place. In most cases and for street use, it probably doesn't matter much. But for the track or extreme conditions it may be a different story.
Sorry for being over-cautious but I come from the nuclear world where engineering often took a huge number of variables into consideration. And without a solid understanding of all these variables, it was easy to get in trouble.
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It's a valid concern that painted bolts indicate QC procedure. Typically, we use a colored dot to denote loctite (blue, green red). A line (swipe) with a grease pen is used to indicate final installation. Once the part has been installed and torqued, the line will show if the bolt backs out or if maintenance has been performed. Perfectly lining up the mark after maintenance is more work than most techs care to do, so it's a good indicator. If the bolt is realy at risk of backing out, cotter pins and safety wire will be used. You won't see many of these on cars (besides the axles), because it's cheaper to overdesign.
As far as reusing the mounts, the factor of safety on those bolts is insane. In single shear mounting, bolts can handle ALOT of force. Most of the load is shared by the structural pieces you're connecting. The reason an engineer would overdesign them, is when the nut walks out... the force is no longer shear (in plane), it becomes bending (out of plane). Strength drops alot. You have to design around bad mechanics and neglectful high schoolers. If everything is tight and properly aligned, you could probably hang the car from those 4 bolts.
Here's a question for ya'll. Have you ever seen a broken strut tower bar? It doesn't happen very often. When they do though, it never happens on the bar itself. Failure is many times due to over-tightening of bolts or shock loading causing failure at a weld/bend near the mounting plate.
The gussets on the GS bar mount seem to be pretty robust in that regard. Not too worried about them finding real estate for a logo either... everything they fab up has G*S etched/laser cut in it.