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All bolts stretch when tightened. They never completely return to the factory new length when removed. In many applications that small change has no impact on service life, but in the LDT/LDS it seems to be a factor. Or it could be the torque applied during rebuild... we don't know.

We could all build race/puller engines if we wanted. I'm a bit more interested in finding out why the rebuilds are chunking rod bolts. If the data works out that these bolts were damaged by re-use or something in the rebuild process, simply dropping in new bolts covers the bases for 99% of us.

Unless there is a clearance issue physically removing them while inside the crankcase, then there should be no issue. Resizing compensates for wear on the rod, but it is not required. Edit: While you're there you might as well drop in rod and main bearings if required. Honestly, these...

Simple test. Find a broken bolt and a good used bolt in the same engine and have a NDT check done for metal fatigue. Do the same for a non-rebuilt engine. I'm sure someone has one that lost a head gasket or was just spanked some other way. If it is metal fatigue from something done in the...

4140 would be a high grade bolt. The final temper would probably be a treatment AFTER the threads were made... but most likely grade 8. I don't think the issue is cheap bolts per se, but that they are under great stress due to the balance tolerance they were exposed to, age, and the fact they...

The balance on the LDS/LDT is a bit odd. They swapped solid vs hollow wrist pins and two different piston castings without changing the balance on the crank. VASTLY greater changes in mass than a swap of differing grade bolts... But, I have no doubt that is a factor in the high-RPM failure...

As long as those are USA made replacement bolts, I think we have a winner. It was re-torqued/reused bolts that were causing the problems if I recall. Maybe my 1985 production non-rebuilt engine is looking better.

Who made the original bolts? That tooling could still exist in someones hands. Possibly a similar bolt for a different application?

Anything ever come of this? Was another source found?