Installing Headers bolt order?

[V6UnderPressure]

Just curious as to which bolts to put in first, which to tighten first. Basically Im looking for a good procedure that will help me make sure they are sealed!

Scott

 

[blackbuick87]

Start in the middle and work your way out. I did the studs last, since they were easier to get to

 

[V6UnderPressure]

Could you possible clarify. What I really need to know is, do you snug the middles first, then outters, then tighten middles, then outters, or do you just go ahead and tighten the middles first completely and then put the outters in and tighten them completely?

Scott

 

[tom h]

I would tighten header bolts in 2 or 3 steps, working from center outwards.

eg,

finger tight assemble headers AND crossover pipe.

HEADERS:
center bolts to 15-20 lbft,
then outer bolts to 15-20 lb-ft

repeat, but to 35 lb-ft (spec)

repeat one more time, to 35-40 lb-ft

CROSS OVER
tighten to spec (forget what it is).


Also suggest Permatex anti-seize on all bolt threads, either nickel- or copper-based.

 

[ijames]

Definitely get all the bolts started before tightening anything. Then snug from the middle out, then torque from the middle out. Also, if these are the ATR tubular headers you will need to start one bolt on the driver's side (maybe the second one from the front?) first and tighten it to bring the header up to the head. You can't get this one bolt into the hole if you already have other bolts in holding the header close to the head. You can tell which hole it is by looking with the headers on the bench, but it's real frustrating to find this after starting several other bolts .

 

[tom h]

on some of the header bolts, especially the #6 cylinder, there isn't enough room to insert the head of a torque wrench.

rather than "guess" at the torque, using an accessory called a "torque adapter" will help. Looks like a mini-box wrench. One end is the 12point box, other end is a 3/8 square drive for the ratchet.

Center-to-center distance between nut & square drive is typically 2.0", so that small compensation for the torque setting can be calculated.
Exmpl, if torque wrench is 12" long from grip to head, with the torque adapter installed you'd be applying 14÷12 = approx 15% more actual torque, than the torque wrench says.