torque specs on aluminum intake?

[davek]

why do they say 30fp on an aluminum intake? I never knew the reason so thats why Im asking. Is it because its soft material?

 

[69Bee]

What aluminum intake? Edelbrock states 25 ft/lbs for theirs. Always follow the manufacturers spec.

 

[WP29440SE]

I go to 30 on aluminum and 40 on cast iron. aluminum has the potential to crack if it's over tightened.

 

[davek]

Never knew it would crack,On my charger I torque to iron specs. Learn something new today.

 

[Don Frelier]

Aluminium expands more than iron when heated. So it pushes out on the fasteners

 

[alfaitalia]

Another reason it needs less torque is because the bolts will be tighter when it gets hotter as aluminium expands more than steel when hot. Twice as much in fact....depending on grade of iron (steel is the same) or the mix of the aluminum, the coefficient of linear expansion is around 2.4 for aluminum and just 1.2 for steel/iron.