What grade fasteners are used in the assembly of engines. What makes one company like ARP beter than someone else.

 

Aftermarket are grade 8. 180Kpsi

 

so Grade 8 bolts with the right head, length and thread from the local hardware store would work or not.

 

Should be grade "8" with five slashes on bolt head. ARP fasteners are rolled threads which are stronger, most others are machined threads.

 

The bolts that came off the main bearing caps have an x thru them what does that mean

 

Stock internal engine fasteners on Chevy, Saturn, Ford, American Honda, Cadillac, Caterpillar, Navastar, and Buick engines are ANSI/ASME grades 8 or "Super" (beyond Grade 8) or ISO 10.8 and higher. At least all the millions of bolts delivered to them from Textron/TFS were that way in the 18 years I was there. All got tied down to teat for hydrogen embrittlement after heat treat, scanning electron microscope inspected for crystalline structure, and hand inspected for defects. Most were hard thread rolled AFTER heat treat for the stongest possible threads. It was hell on dies but made a good fastener. None of them got any finishing more than black oil or phoshate coating. And most of them never got grade or manufacturers' markings since the formations are a possible stress riser and failure point.

Aftermarket bolts profess to be "superior quality" when in fact they are only new. New bottom end bolts and studs should always be used in a build up.

Despite what you might presume to be "average" quality in the typical engine, most manufacturers were stingent about internal engine fasteners and didn't cheap out on quality there. Honda was probably the hardest to deal with, but none of them were a pushover. None of the big guys liked recalls, and you never know what kind of cowboy is going to get behind the wheel and redline a cold engine that is still under warranty. I think they covered their butts pretty well.

 

So.....I think you are trying to tell me to use new bolts. I did. I used ARP bolts that is the one that broke. If understand your reply, aftermarket bolts are not necessarily better than what you get from the dealer. They are just new so where to get bolts from what source. What source would you get them from?

 

ARP is a small manufacturer, and they don't even finish in-house. They were among the very LAST automotive fastener manufacturers to earn ISO9001 and QS9000 certifications in the business. They're just a small-time player with a lot of advertising in a specialized market. And we all know that a big advertising budget makes the product that much better.

No serious fastener manufacturer has used cut threads on anything except wood screws since the 1960s. Not Camcar, Elco, Ring Screw, Rockford Products, Southern Screw - no one. Hartford Special Machine invented the modern flat die thread roller in the 1920s, and they have been used extensively ever since. Reed Tool invented teh rotary die roller, and those are fairly common as well, but they still roll the thread, knurl, or lobe.

Everything is rolled, and even most wood screws are now rolled. the difference in high strength fasteners is that they are hard rolled - after the heat treat process.

 

The dealer can sell you a bolt kit, or you can go back to ARP and complain, asking for better hardware.

Industrial fastener suppliers are a good source for specialized hardware, but you have to specify exactly what you want in terms of tensile strength, elongation %, and shear.

 

few thing that might make you stay away from common hardwear bolts for head or main bolts is the reduced body behind the threads, this reduces or eliminates a stress riser and makes a better bolt and under the hex the bolt shank is full size again. never saw an ARP bolt break new. i'll bet if they care anything about quality they'd want it back to take a look at it.