Comptech Header Adaptor Ball Joint Torque Specs?

[NSX-Files]

I'm installing new Comptech Headers on my 1991 NSX. The system uses the adaptor pipes with ball joints and springs for tension that fit between the end of the headers and the cats. The installation instructions don't give a torque value for the spring loaded bolts and nuts and I couldn't find anything in the Prime archives.

Anyone know what the torque value should be? TIA

David

 

[swerve2007]

use the standard torque settings for bolt size- i think the manual has the table.

 

[NSX-Files]

use the standard torque settings for bolt size- i think the manual has the table.

Thanks for the reply. My concern about that approach is that the torque values for a normal fastener would assume you're not compressing a spring. Since the header uses springs, you don't want it to totally compress and bind the spring down, right? So the torque value needs to be lower than standard based only on bolt size?

 

[angus]

the bolt was designed with this in mind , if you are binding the coils it not the right bolt, but I have seen them instaled like this too , without issues
just tighten them up and forget it

 

[nigel]

There is no real "torque value" per say as the bolt and spring assys. are designed to allow some movement in the exhaust system as the engine flexes under torque and twists and the spring tension vary from exhaust system to exhaust system.
Tighten the bolts to the point of partially compressing the springs but not so far as to bottom or coil bind them.
This is the exact same bolting system used on all 300 and 400 series Cessna twins and any piston eng. aircraft with good exhaust systems.
In aviation they use a bolt and nut with a cotter pin to avoid the nut from backing off and it holds a constant pressure after it's tightened.
I used "-3" AN bolts and high temp nuts from aircraft with "Gold" anti-sieze.

Cheers
nigel

 

[NSX-Files]

For anyone doing this job in the future, I figured it out (some people that responded probably already knew this but I didn't "get it" until I went to install the bolts).

Note that the springs and bolts for connecting the adapter to collector are designed with a "shoulder" on the bolt to "bottom out" against the collector flange. So there is no need to guess about how much tension to put on the springs. You just tighten the bolt surrounded by the spring until the bolt shoulder bottoms on the flange and you're done. The tension on the spring is therefore factory set.