425 vs 455 and 330 vs 350 Damper Bolt Torques ??
#1
425 vs 455 and 330 vs 350 Damper Bolt Torques ??
Anyone got the lowdown on torque values for damper bolts on '65 - '67 motors vs '68 - up motors?
In the manuals for '65, '66, and '67 the torque is specified as 50 ft/lbs.
In the manuals for '68 and up the torque is specified as 160 ft/lbs minimum.
There is no discernable difference between the crank ends, dampers, or bolts.
I would ASSume that the change is not because anything about the engines changed, but because GM realized the old spec. wasn't enough.
Do I ASSume correctly?
Any juicy stories from the old days behind this one?
- Eric
In the manuals for '65, '66, and '67 the torque is specified as 50 ft/lbs.
In the manuals for '68 and up the torque is specified as 160 ft/lbs minimum.
There is no discernable difference between the crank ends, dampers, or bolts.
I would ASSume that the change is not because anything about the engines changed, but because GM realized the old spec. wasn't enough.
Do I ASSume correctly?
Any juicy stories from the old days behind this one?
- Eric
#3
socket, 1/2" drive breaker bar and a long cheater up against the frame, give the starter a whirl and it doesn't take anything but a turn of a key Of course, if you wait to do this until AFTER you take the engine out you're back to a mile long cheater bar and 4 friends to help lol!
#4
Early 65 cranks had a smaller bolt, hence the lower torque. Olds found some issues with the bolts loosening so went to 3/4 fine thread bolts (1.125" head) in mid 1965 iirc. It took time for the service manuals to catch up. All the big bolts are taken to 160 ft lb.
#5
Okay.
So they changed the bolt in '65, but they didn't change the manual till '68.
Typical, no?
There must be a service bulletin saying, "Ignore the manual - just torque it to 160."
Thanks for that.
It makes sense, and I knew there would be some kind of a story.
- Eric
So they changed the bolt in '65, but they didn't change the manual till '68.
Typical, no?
There must be a service bulletin saying, "Ignore the manual - just torque it to 160."
Thanks for that.
It makes sense, and I knew there would be some kind of a story.
- Eric
#7
Great idea, J, and Thanks!...
But no thanks - Now that you've given me the idea, I can weld one up myself if I need it, and save you the trouble of packing it .
- Eric
But no thanks - Now that you've given me the idea, I can weld one up myself if I need it, and save you the trouble of packing it .
- Eric
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