Problem: Copper anti seize on aluminium head exhaust studs (1 Viewer)

[bikemaniac]

Hi,

The more I read the more I get confused.

Application is either steel or stainless steel studs (used for the exhaust manifold) mounted in an aluminium head. Or any bolt or screw mounted in an aluminium head.
I need an anti seize to prevent bolts/studs from twisting off during disassembly. Even after YEARS of service in salty, humid climate.

Now, some claim to never use copper based anti seize in aluminium heads. You have to use aluminum based, nickel based or ceramic based. The other group says that copper is the best thing to use, even in aluminum heads. From a theoretical point of view there SHOULD be an issue due to galvanic series of different metals, but what happens in the real world?

I know copper is used from a traditional point of view (*we always did that even 40 years ago*) - but how often will the very same mechanic remove the studs/bolts from the very same car he fixed 5-10 years earlier to actually see and experience what happened? I also know many mechanics switched to aluminum versions since they are less toxic and even further on to ceramic versions. But then again I hear that the ceramics don't perform as well as the old copper stuff.

Anyone with some insight?

Lucas

 

[billymagg]

Hi,

The more I read the more I get confused.

Application is either steel or stainless steel studs (used for the exhaust manifold) mounted in an aluminium head. Or any bolt or screw mounted in an aluminium head.
I need an anti seize to prevent bolts/studs from twisting off during disassembly. Even after YEARS of service in salty, humid climate.

Now, some claim to never use copper based anti seize in aluminium heads. You have to use aluminum based, nickel based or ceramic based. The other group says that copper is the best thing to use, even in aluminum heads. From a theoretical point of view there SHOULD be an issue due to galvanic series of different metals, but what happens in the real world?

I know copper is used from a traditional point of view (*we always did that even 40 years ago*) - but how often will the very same mechanic remove the studs/bolts from the very same car he fixed 5-10 years earlier to actually see and experience what happened? I also know many mechanics switched to aluminum versions since they are less toxic and even further on to ceramic versions. But then again I hear that the ceramics don't perform as well as the old copper stuff.

Anyone with some insight?

Lucas

We always used a copper based anti seize on aircraft spark plugs,, don't use more than you need and torque to spec,, it will be fine,, Billy

 

[cody c]

I use the nickel based Nikal-coat by jet-lube or loctite, I believe it has a higher temp range than copper.

Expensive stuff but it is the best product for the application IMO.

Over the years in industrial construction (O&G) there is a ton of this stuff used and it seems to be the best stuff out there, commonly used with stainless swagelock fittings.

 

[OSS]

Toyota never uses anti-seize on anything in any of its vehicles. That says something. But also they are using freshly plated fasteners.
The problem occurs when REUSING old fasteners that are corroded. That’s when the seizing begins.

Screwing a stainless steel bolt or stud into aluminum is asking for seizing. The two metals hate each other (or maybe love each other).
Goooogle that.
Ideally the best fastener to screw into an aluminum Toyota part is a new Toyota bolt or stud.

 

[Malleus]

IME, the studs don't stick in the head, it's the nuts that are designed to crimp onto the studs that won't come off. Unless you're removing your headers fequently, like more than once in the life of the engine, just replace the studs and nuts and save worry for something important.

 

[cody c]

Toyota never uses anti-seize on anything in any of its vehicles. That says something. But also they are using freshly plated fasteners.
The problem occurs when REUSING old fasteners that are corroded. That’s when the seizing begins.

Screwing a stainless steel bolt or stud into aluminum is asking for seizing. The two metals hate each other (or maybe love each other).
Goooogle that.
Ideally the best fastener to screw into an aluminum Toyota part is a new Toyota bolt or stud.

Just to be a contrarian, but I don't think any of the toyota engineers back in the 80's and 90's live where the roads are salted. Just a guess based on how well the body panels last in the north.

I'm sure there are arguments to both sides, but having pulled off a few exhaust manifolds on 300,000km+ Bj60 cruisers etc, I do and will always use the nikal-cote for those applications.

If the bolts were rattling use I'd look at a different product, but I've had to deal with broken/rusted studs (most of this was for turbo'ing 3B motors and head gaskets) but I'd much rather snug up a loose bolt than deal with a seized one in this situation.

Living in the desert or an area much less susceptible to rust, it may make sense not to though, different risk/benefit ratio.