HEADER BOLTS TIGHTENING TO ALU HEADS

[calais1965]

Is there any torque value for tightening header bolts to champion aluminium heads?

 

[Paul Lohr]

Usually I can't get a torque wrench in around headers so I have to tighten by feel.

If this were my vehicle, I would tighten the bolts enough to compress the gaskets and put a little tension on the bolt assembly. This isn't much torque. Then drive the vehicle to get everything hot, let it cool, tighten the bolts a little more. I usually find a few bolts that are looser than the rest. Drive it again, let it cool, check the bolts again. If the flanges are flat and the gaskets are decent this procedure keeps the headers sealed up for a long while.

Paul Lohr

 

[calais1965]

Torque specs for iron heads are 50 newton metres, I have thinked to use 40 nm for aluminium heads.

 

[coach]

Use studs and nuts...not bolts.

 

[calais1965]

Bolts came with my headers. I should order studs for these, do you use locktite for studs?

 

[Nick Micale]

You can get "studs" which are actually Allen set screws at your local hardware store. This will make is easy to install and remove them.

The use of a flanged 3/8" nut will keep them tight after re-torquing when the gasket is completely compressed.

I have never seen the need to loctite studs in alum heads.

 

[calais1965]

Ok, thanks guys!

These are best for securing bolts. http://www.nord-lock.com/

 

[coach]

Bolts came with my headers. I should order studs for these, do you use locktite for studs?

The reason for studs in alum heads is the threads are not inserted. Alum threads suck!!! They are extremely weak. They should be inserted. Studs help some of this weakness because you are not twisting the thread to tighten it. Once the stud is screwed in...your twisting the nut to tighten and just pulling on the threads. They are less likely to strip out. To pull a head off because of a stripped header bolt would totally wreck your day.
Do as Nick suggested and get the socket head set screws and use them. That's what I will do.
I may still insert mine before the motor goes in. As a toolmaker/engineer...I cannot stand alum threads.

 

[calais1965]

Ok!
Have to order studs, because i live in finland 3/8 studs are not common in hardware store ( i own hardware store ) ....

 

[frank_ster]

yes use studs and nuts .. the torque value has to be almost the same as steel, other wise they will simply come loose because the bolt isn't stretched.

i'm surprised the heads don't have helicoils built in ???? my sbc heads have helicoils everywhere.

 

[calais1965]

There is helicoils in the threads.

 

[coach]

There is helicoils in the threads.

Not on my GN1's. I asked 2 members here about it, and my builder. All said they use studs. I may install coils before it put in the car.
The rocker shaft holes are coiled. That's it.

 

[jpwalt1987]

Not on my GN1's. I asked 2 members here about it, and my builder. All said they use studs. I may install coils before it put in the car.
The rocker shaft holes are coiled. That's it.

Coach, make sure the rocker shaft holes have a long enough insert. Somehow mine had a short 3/8 long helicoil in it. The pedestal snapped.

 

[coach]

Coach, make sure the rocker shaft holes have a long enough insert. Somehow mine had a short 3/8 long helicoil in it. The pedestal snapped.

I remember. My builder has them, and with his rep for building engines...I'm sure he will check everything out.
Thank you for your concern.

 

[novaderrik]

Ok!
Have to order studs, because i live in finland 3/8 studs are not common in hardware store ( i own hardware store ) ....

i think they are 5/16"..

 

[pacecarta]

arp has a header stud kit with 12 stud sets
they are for the short holes only , wont work for the header holes with the standoffs for dipstick and alt brackets (top bolt holes on stock headers)
http://www.summitracing.com/parts/arp-120-1402

 

[Nick Micale]

i think they are 5/16"..

Sorry but Buick turbo heads iron and alum use 3/8" header bolts.

 

[coach]

Sorry but Buick turbo heads iron and alum use 3/8" header bolts.

Yes...3/8x16...not 3/8x24
A lot of studs are fine thread, so be careful and don't get burnt.

 

[pacecarta]

the studs from arp are nice .
3/8-16 for going into the head.. 3/8-24 fine thread for the 12pt nut

only complaint is the rounded stud end prevents removal install with header in place
what i do is slot the end with a whizzer wheel so i can use a flatblade screwdriver

 

[coach]

the studs from arp are nice .
3/8-16 for going into the head.. 3/8-24 fine thread for the 12pt nut

only complaint is the rounded stud end prevents removal install with header in place
what i do is slot the end with a whizzer wheel so i can use a flatblade screwdriver

Just use the socket head set screws. The Allen head makes it worth it. They do not need to be strong. They are under no load at all