Looking to buy rods very soon. Noticed it says 160, 000 200, 000 180, 000 psi yield. Can somebody explain this a little better to me about what that means. I tried to google it but I just got cars with 200, 000 miles on it. So no luck there

 

I could, but you did no research of your own. Your answer is on ARP's website. As to what you need depends strictly on your stroke, your piston weight, and your RPM range. Power level has nothing to do with it.

 

160,000
180,000
200,000

PSI Yield is the strength of the rod bolts. Typical good rods will have ARP 8740 rod bolts. Next step up from there is the ARP 2000 rod bolts. High end is ARP L19 rod bolts. A basic OEM rod bolt is only 4130

Most engines will do just fine with the 8740 bolts. My race engine uses the 2000 rod bolts but it's also a BBC which can be spun well over 7000 RPM. Very high HP engines which will replace rod bolt regularly will use the L19 bolts. They're very strong but are also not good for long life or high mile engines.

The ARP 8740 3/8" rod bolt has a 190,000 PSI rating.

Good rod bolts add reliability to the engine however it also depends on how you use the engine. As a daily driver, OEM replacement bolts will normally do fine as they've survived millions of miles already.

It's when you start spinning the engine to high rpms with a heavy rotating assembly that good rod bolts are essential.

The rod bolts clamp the cap to the rod. It does very little through the crank rotation except when the piston is reaching the top of the cylinder. The crankshaft is spinning the rod and piston upward and as it reaches the top of the circle, the rod and piston suddenly stop before going back down. On a compression stroke, it's not so bad because the fuel is already igniting on the top of the piston to start pushing it back down again. On the exhaust stroke, the piston and rod are just weight being slung around. At high rpm, this weight becomes very heavy.

Those rod bolts go through a huge amount of abuse right at that period and if a rod bolt fails, the rod and piston will try to go through the head. The higher PSI strength means it can take more stress before the bolt stretches or snaps.

Read these pages. They may help.

http://www.arpfasteners.com/pages/te...l_design.shtml
http://www.arpfasteners.com/pages/te...tallurgy.shtml

 

Ok thanx for the info. I plane on getting eagle ibeams. But I guess after reading your infi I dont want anything to fail. So ill look for 7/16 200, 000psi

 

Wanted to add to this press fit pins should work fine for your application.

 

I was going to get floating anyways