Really dumb question about nuts and bolts

With the exception of specialty fasteners (banjo bolts, head bolts...) is there any reason I can't just run to the tractor supply and get grade 8 bolts to use on my motor? When you start figuring what it costs for the "kits", intake bolt kit, manifold bolt kit, oil pan, valve cover, it just gets crazy. I usually reuse the stock stuff where I can, but I would rather replace a lot of that.
Thanks,
CHAZ

 

Thats all a lot of machine shops do. But for all those things you mention, they usually only use grade 5 since they are not stressed.

 

Thats what i do. Don't really need grade 8 for pan and rocker boxes, but i got them since I found it was cheaper and eaiser to just buy a box of 100 5/16 X 3/4 Bolts and lock washers.

 

most "outside" engine bolts are grade 5, head and main cap bolts are usually stronger than grade 8 or are a funny size, so it's best to use the originals for them, or correct replacements.

I personally like keeping all the original bolts if they're in decent condition, they are generally good quality stuff and look right.

 

Head bolts/studs, hardware for mains and rods are the critical stuff and should be original equipment or GOOD aftermarket like ARP. Most othe rbolts on engine are relatively lightly stressed and even mystery bolts from Home Depot would work...
When I get stuff at the junkyard, I usually grab extra engine bolts from any engines of proper sort I encounter.
For any bolts that can kill you or your engine, buy only from respectable sources...now that so much is imported from lowest bidder, stuff like the number of lines on the bolt head means very little. If the Chinese realize that adding more lines increases the price of the bolt...well, good luck with that one.

 

I buy the most common sizes by the box of 100. Also washers and nuts by the 100.. Keep little drawers full of them. Mostly grade 5 but for suspension components I'll buy grade 8. I've bought "kits" from ARP... like head studs, rod bolts and main studs. I love ARP stuff but it does get expensive.

 

I like using stainless, allen head bolts on the exterior bolt, ie:intake, WP, etc.....hardware store stuff is fine....
Head, mains and rods are step shouldered to properly index/center the cap/head.....

 

I am talking about exterior bolts. I would consider the more critical stuff specialty. The local tractor supply sells all the stuff of the same grade for the same price per pound. Just fill up a brown paper bag or two with what you need, what you think you might need, and a few spares.
Thanks,
CHAZ

 

the look of the hardware can make or break the look of an engine or car. the look of most stock stuff is much better then cheap hardware store bolts. hardware store washers always look like crap because the hole size is always to big for the size listed and they end up sitting off center from the head

 

There's a place here called Fasnall that sell bolts by the bag of 10 or so. It's a lot cheaper to get the stuff there than at the local hardware store.
I just bought a bag of 5/8's grade 8 fender style washers for 4 bucks to use on my heim ends.

 

Another great source would be your local Caterpillar dealer......their bolts are tough and have a nice black oxide finish......

 

For non-load bearing stuff I use stainless. Usually 1/4" x 20 by the box. Grind the head smooth and polish it. Never use stainless in a shear situation because it is weak. Note that most nuts and bolts today come from off shore and the actual Rockwell number is in question. On some of the newer applications a torque-to-yield bolt is uses. Never reuse this type of bolt because it WILL fail the second time around.

 

Cat also has the rights to the old MOpar flat sixes. I built mine 20 years ago with all CAT parts!
Those Cat logos on all the head bolts looked tits!

 

We just went into our locxal Fastenal whre we have been buying bolts etc by the piece during our 32 build. They no longer sell anything except in box quantities just like other fsatener houses. Damn it!

 

Our local Fastenal still sells whatever quantity is needed.

 

A lot of OEM bolts and fasteners have very subtle differences from off the shelf items, different thread length, maybe a built-in shoulder, maybe built-in channel for oil or water flow, flanged head, built-in washer head, etc. I prefer to use OEM style when possible, although I will certainly use off the shelf items if it means riding instead of walking.

 

Most OEM bolts are flanged to include a washer in the bolt head. Using generic bolts you're pushed to a washer, which isn't precision fit to the bolt and looks sloppier than a one piece bolt. You may also find the factory used smaller head sizes for a given thread, because of interference. There's a reason why so many SBCs run header bolts on the intake!

I often use hardware store fasteners, but usually end up in the specialty bins instead of regular grade 8.

Good Luck!

 

I worked on aircraft and rockets for the government for alot of years before I retired. Having said that, when you toque a bolt it actualy stretches the bolt a minute amount. Needless to say reusing a bolt is taking a chance at best, it may last forever or it may break from stress. There is running torque, and minimum torque and many others. Best rule of thumb is use the best quality you can especially if your loved ones are going to ride with you. Rags