In putting my 260 engine back together again, the shop manual
indicates that connecting rods should be torqued to 22 foot pounds.
This seemed a little "light", so I consulted a Chiltons from the
period and it indicated 40 to 45 foot pounds. The "Performance
Tuning" book indicates 44 foot pounds. I decided on the "two out of
three" figure of 44 foot pounds. I took the torque up in 3 stages
(15, 30, and then 44). 30 was fine, but I never got to 44 before
twisting off the first rod bolt.
The rods are stock items. Perhaps I was lucky that I found a bad rod
bolt now while it was on the engine stand, or maybe 22 was really the
right number, and if so I have probably overstressed all the rest of
the bolts? Can I substitute new hardened rod bolts into the existing
rods without taking the rods to a machine shop to "resize the big
ends"? Or should I just take a step back now and replace all the rods
with later model, heavier duty pieces?
The engine is going to be used "moderately". It will have an
Edelbrock Performer cam (not Performer RPM), steel 289 heads with big
valves, screw in rockers and guide plates, an F4B / 600, and Rick's
headers. It has been bored 40 over by a PO, and apparently not too
many miles ago, as the cylinder bores and pistons are still within
spec.
Any advice and guidance would be appreciated. Thanks.
Doug Babcock
B9471598
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