I tried posting this on the exhaust board with no replies. I know there's plenty of guys on here that are running headers with aluminum heads. I have a buddy putting headers on his aluminum head LT1 motor, and he's wanting to use blue loctite on the bolts. Is this a good idea with aluminum threads? My suggestion to him is to use anti-seize on the bolts and use a good set of lockwashers with the bolts. Anyone know which way is the best route to go when you have aluminum heads? Thanks.

 

Loctite probably won't do much in that kind of heat. Stainless header bolts are a good idea, especially if the heads aren't helicoiled already.

 

how about safety wire? or use a stud with red loctite, and a stover nut.

 

Studs aren't the most convenient thing to use with headers, and even if prevailing torque nuts don't back off, you'd need to make sure the studs themselves won't back out of the heads.

 

I've heard of people using green locktite on the bolts.

 

green loctite??? what's that?

 

I never mess around with Loctite. Especially not on header bolts. Cynoacrylate glue (Superglue) won't hold up to that kind of temperature.

Heli-Coil the heads if they aren't already, so the threads don't wear from the constant motion that headers produce; and use lockwashers, safety wire, locking bolts, etc. if you're concerned about the bolts loosening.

Studs nuts won't work any better than bolts, since the studs can back out of the casting the same as bolts. Doesn't matter how well the nut is locked onto the stud if the stud backs out.

 

Green loctite is for securing bushings into reamed holes.....not for bolts at all

 

Never even bought green loctite before. I use the blue stuff(med. strength) if it's something I'll be undoing again later, and the red(high strength) for permanent stuff. The red is also great to use on heli-coil inserts when installing them. Either way, I told him I probably wouldn't use loctite anyways. I'm thinking either anti-seize on the threads and a good set of lockwashers, or nothing on the threads and lockwashers. Anti-seize helps prevent the threads from galling since it's two dissimilar metals you're dealing with(steel bolt/aluminum threads). When I worked at a garage, we always used a little anti-seize on the spark plug threads before installing them in any aluminum head. Heli-coils are by far the best thing to do to any aluminum thread, but I doubt he'll want to spend the money or the time to heli-coil all the bolt holes with the motor still in the car. Thanks for all the input guys!

 

you should always use antisieze on anything in alumnium. then just check the bolts every once in a while.