No loctite - ARP assembly lube only and go buy a rod bolt stretch gage - its the only true way to get the right pre-load on the rod bolts. Torque values can be mis-leading for a variety of reasons.
Measure and record the new bolt length using cone tips on a micrometer. Then stretch it as below.
I cycle all my rod bolts at least 5 times using a calibrated torque wrench (I get mine calibrated before every engine build or 24 months which ever comes first) with ARP lube. Then measure the length again - if they have stretched more than 0.002" from the new state then don't stay in the engine. Once I know the bolts are good then the last tighten is done using a rod bolt stretch gage.
On ARP rod bolts typically when installed using the stretch method - the resulting torque is a lot high.
On the next tear down if the bolts have yielded - they get replaced. It costs a bit more to do it this way but the overall cost is peanuts compared too the cost if a rod lets go.
Note - if your replacing std rod bolts (ones with a forged head on them)with ARP ones - I usually install them using a hyd. press after I torque them up and release them - this ensures the bolt is seated in the rod properly. Use a piece of aluminum against the rod split line to protect the face. I suspect that your bolts were not fully seated and once they ran a bit they did so but also lost the applied torque.
Last edited by efi-diy; 07/06/15 01:59 AM.
