Rod bolt stretch

[jay dcpt]

Arp 2000 rod bolts. Spec is max .0064 stretch. I came in at .007 on two of them. Would you back them off and seek up on the spec? Or would you be comfortable with .007? I'm thinking there could be a lot of human variables when taking measurements.

 

[jay dcpt]

Brand new molnar rods.

 

[Turbo6inKY]

Arp 2000 rod bolts. Spec is max .0064 stretch. I came in at .007 on two of them. Would you back them off and seek up on the spec? Or would you be comfortable with .007? I'm thinking there could be a lot of human variables when taking measurements.

Measure again. If it's still beyond spec, replace the bolts. Period. The bolts are cheap compared to the big end of a rod coming apart on you. Molnar will sell you individual bolts. Just call them up. They're super nice people.

 

[jay dcpt]

Your right. I redid it today. All bolts within spec. I was just being lazy.

 

[jay dcpt]

Had a very nice conversation with Ed at molnar today. Basically he said not to think twice about it, was going to order new bolts. Ed said you can take that bolt up to .0085 and still be fine. Spec is 30 lb ft + 60 degrees. Ended up doing 30 lb ft + 45 degrees then snuck up on the .006 with the stretch gauge. Torque for all ended up being high 70s ft lbs according to my torque wrench.

 

[turbodave231]

The way to tell if you stretched a bolt too far and damaged it is to loosen the bolt and remeasure the bolt overall length. If you exceed the elastic limit of the bolt, it will not return to its original length (and should be replaced)