Eagle rods and higher rpm

[er82]

I've read on several forums that high rpm kills eagle rods. What rpm would that be on a dsm? Would the ARP upgraded rod bolts, p/n 300-6703, reduce that risk? And would cryo treatment help as well?

 

[BogusSVO]

What are you calling "High RPM"

 

[er82]

What are you calling "High RPM"

9000 rpm. I'm sure there are a lot of factors involved that will determine the rpm limit for a particular setup. But 9k is the most I would consider.

 

[BogusSVO]

For 9k RPM, you may want to consider a bit better rod and piston combo, more so if you are going to be that far up on a regular basis, or extended period of time.

 

[er82]

For 9k RPM, you may want to consider a bit better rod and piston combo, more so if you are going to be that far up on a regular basis, or extended period of time.

I see. I was under the impression that for power need thicker rods and for rpm need better rod bolts. But there may be no reason to go beyond 8k rpm due to oil pump limit.

 

[bastarddsm]

It had to do with the load reversals. The higher the peak to peak load the less life they have. I did some engineering work on them, and assuming that there are no flaws in the metal, they should have basically an infinite life at 600ft*lbs of torque. The loads from rpm were very low compared to the loads from combustion. I don't think I ever looked at the bolts, but everything uses the same arp bolts. My manley turbotuffs use the same bolts and I go 9500 with it all the time.

One note, the very early eagle rods used 5/16" bolts, so as long as yours use the 3/8" your good.