Author Topic: Any Issues I'll encounter: C3 CI Long Tube headers off Edel Heads?  (Read 554 times)

0 Members and 1 Guest are viewing this topic.

FERoadster

  • Sr. Member
  • ****
  • Posts: 492
    • View Profile
Will the weight of the headers pull studs out of the aluminum heads?
2nd question what porting will I need to do to get good exhaust flow into 3" exhaust system realizing the C3 Headers have a 2.5" outlet?

Richard >>> FERoadster

428kidd

  • Sr. Member
  • ****
  • Posts: 414
    • View Profile
No the weight of the headers will not pull the threads out. As long as they fit your chassis, then you will be fine running them. As far as porting the exhaust, i dont think it would be worth the effort unless your looking for every bit of power out of the engine. 

FrozenMerc

  • Full Member
  • ***
  • Posts: 168
    • View Profile
Your worried about the wrong thing.  Typically torque values on hardware are designed to generate a tensile load in the bolt of 75% of the proof load of that bolt's material, but this is obviously based on a nominal friction coefficient of the joints components (bolts, nuts, washers, etc.).  So, for example, a 3/8" UNC Grade 8 bolt torqued to 33 ft-lbs on the nut side would nominally generate about 7,000 lbs of tensile (clamp) load.  I.E, that is 7,000 lbs of force trying to pull the stud out of the cylinder head, much, much more than the weight of the headers which is distributed across 12 or 16 fasteners.   

The much bigger concern is a fastener / nut combo that does not have the correct friction coefficient.  Too little friction leads to very high clamp loads that can damage the joint by stripping threads, yielding or pulling the bolt apart, or crushing parts of the joint (gaskets, bushings, etc.).