tommyboy Posted August 16, 2007 Share Posted August 16, 2007 I'm rebuilding my engine and wanted to replace some of the old bolts on my car with new stainless steel ones (they're prettier). The only problem I'm having is that I don't know a lot about bolt expansion because of heat changes. So, I was wondering which ones I could replace in spots where you can actually see the bolts i.e. thermostat housing, valve cover, etc. I don't actually care about the ones you can't see. Anywho, thankx a lot. Quote Link to comment Share on other sites More sharing options...
johnc Posted August 16, 2007 Share Posted August 16, 2007 No real thermal expansion issues with stainless bolts in the applications you mention. Just be aware that stainless fasteners can gall and sieze up when tightening so use a lube on the threads. "Thread galling seems to be the most prevalent with fasteners made of stainless steel, aluminum, titanium, and other alloys which self-generate an oxide surface film for corrosion protection. During fastener tightening, as pressure builds between the contacting and sliding thread surfaces, protective oxides are broken, possibly wiped off, and interface metal high points shear or lock together. This cumulative clogging-shearing-locking action causes increasing adhesion. In the extreme, galling leads to seizing - the actual freezing together of the threads. If tightening is continued, the fastener can be twisted off or its threads ripped out." Quote Link to comment Share on other sites More sharing options...
tommyboy Posted August 16, 2007 Author Share Posted August 16, 2007 Sounds good. Thankx for the help John! Quote Link to comment Share on other sites More sharing options...
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