Can someone point me towards an easy source for engine bolts for an Lycoming O-320? I just need as few individual bolts and don't need the whole bolt kit.
Thanks
 
Use Grade 5 bolts, marked with three lines on the head, which can usually be obtained at the auto/engine parts store or from some hardware stores. I have purchased them from a local Ace Hardware, which has a really good selection of bolts and other hardware.
 
Yep, this seems to be the only place where hardware store bolts are OK on an airplane.

Hard to believe that a brand new $$$$$ aircraft engine will come with the equivalent of hardware store bolts holding it together isn't it?

You can buy your hardware store bolts from an aircraft supply company but you will end up with the same hardware store bolts but at a much higher price.

Just be carefull and use the correct sized bolt as called out in the parts manuals because the smooth part and the threaded part of the bolt can be an issue. You do not want threads fretting the inside of your case holes.
 
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grade 5 bolts

Thanks for the pointers guys. My local Ace hardware doesn't stock 1/4-20 in Grade 5. Just curious, are grade 8 bolts acceptable?

Also, do you know any specific tractor supply or Auto parts chains that stock them?

Thanks again,
John
 
Check your local Nut & Bolt or Industrial Supply franchise. We have a Fastenal and a Nut & Bolt Bin nearby in our city/county of 65,000. They don't stock AN hardware but can special order the stuff in a pinch.
 
Don't use Grade 8, these engines actually move around a little, and you could POSSIBLY snap a grade 8 instead of just stretching a grade 5.