Correct bolt material for aluminum blocks

[N8Bishop]

So i have seen quite a bit on here about stuck and stripped screws, but not much on why they get stuck in the first place. After a little research i found an annoying little process called "galvanic corrosion". Here's the quick and dirty: nobel metals (less reactive like steel, ss, silver, etc.) Tend to corrode less Nobel metals (more reactive like aluminum, magnesium, etc.). we have steel bolts in many aluminum parts (not really a design flaw, just a nescessity when using lighter metals). As the less noble metal (aluminum) corrodes it gums up the threads and seals the bolts in place. This means that stainless steel bolts in an aluminum block are a bad thing for our blocks it would seem... so the questions:

1. do our blocks have special inerts or is the aluminum just threaded?

2. what bolts should we use to replace worn or corroded ones (i.e. will stainless bolts really cause a problem)?

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[N8Bishop]

BTW, I only thought about checking out corrosion because someone on here mentioned the zinc screws corroding in the carbs. Since I have been saying I want to swap all my bolts to stainless sockethead bolts i figured I should look into if it was the right choice... Can't remember who it was that said it, but a big thanks all of you who have supplied such great information. I have learned a ton!

 

[16VGTIDave]

I just use anti-seize compound on the threads of bolts and screws. Works like a charm every time...

 

[Scorpio1963]

To answer part of your question the only insert our blocks have is the steel piston sleaves other than that the rest is just threads made into the aluminum.

 

[N8Bishop]

Cool, thanks. I also noticed that i left out the most critical part: electrolytes. Without an electrolyte (like impure water, saltwater, etc.) There is no galvanic corrosion. Never used antisieze, is the point to keep out water? That would certainly fix the corrosion issue... i assume there is a high temp antisieze at any parts store?

One last thing: is it safe to use stainless with antisieze?

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[16VGTIDave]

Anti-seize does a couple things all at the same time. It acts as a high pressure lubricant on the threads so that friction doesn't cause incorrect (low) torquing of the hardware, or galling from friction. It contains sacrificial metals that will corrode before the hardware does. It helps seal out moisture.

Stainless steel can still corrode - it is "stains less than high carbon steel" not "corrosion proof" steel. And yes, anti-seize compound is recommended as stainless steel hardware is typically softer than hardened steel hardware and is prone to galling.

 

[N8Bishop]

I like the look of stainless, but I'm not dead set on it. What is the best steel (ir maybe the stock material) to use? Regardless i will be using antisieze! Thanks Dave!

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[16VGTIDave]

Nothing wrong with using stainless hardware in non-stressed applications. For example, don't use it for suspension or brake applications. Engine covers and trim pieces are no problem. Just make sure to torque the fasteners to spec. Most people over torque most everything in the hope that it won't come loose or leak. And that is where the problems begin!

Glad to help!

 

[N8Bishop]

Great, thanks! Any brand of Anti-seize you prefer? Any that are better for high temp applications?

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[16VGTIDave]

I've been using an industrial anti-seize compound called "2000 Anti-Seize Thread Compound". Had the can for over a decade and can't read much off the label anymore, sorry. It has a synthetic base and is rated to 2000F if that helps...

 

[Lou Ranger]

Interesting discussion. I have never had or used an anti-seize product though I have wished I had. It might save on PBBlaster later on.
This manufacturer makes at least 3 types of various temperature ratings - with copper, nickel and silver.
I am willing to buy one can but not 3 - lol.

http://www.grainger.com/Grainger/anti-seize-compounds/lubricants/lubrication/ecatalog/N-9iq
​

Any thoughts on which would be best?

PS - do-it-yourselfer ALERT: http://www.ngksparkplugs.com/pdf/tb-0630111antisieze.pdf

 

[Lou Ranger]

Looks to me like "Marine" grade might be the best for what our bikes encounter on the roads:

http://www.meyerplastics.com/adhesives_seal_tape/anti-seize_comp_sht.htm​

 

[16VGTIDave]

NGK should have advised that "all spark plugs should be torqued to specification". Rather than saying "if anti-seize is used on our flimsy spark plugs, and they are installed by a ham fisted gorilla mechanic, they will break. Don't use anti-seize with our crappy plugs, risk screwing-up your engine instead."

Wow. The more experience I have with NGK products, the less I like them.

 

[xschris]

With any bolt DON'T OVER TORQUE!!!!

 

[Lou Ranger]

With any bolt DON'T OVER TORQUE!!!!

Especially not the the oil filter cover bolt . . .

... Rather than saying "if anti-seize is used on our flimsy spark plugs, and they are installed by a ham fisted gorilla mechanic, they will break. ..

.. Don't use anti-seize with our crappy plugs, risk screwing-up your engine instead."
...

Dave. I should clarify. This was not an NGK release directed just to the xs400 Forum.

 

[16VGTIDave]

Dave. I should clarify. This was not an NGK release directed just to the xs400 Forum.

Oh, I got that Gord. It was, however, for the size of plugs used in our DOHC motors.

I'm going to do some checking around before my next plug change. There has to be plugs out there that are more robust and less temperamental than NGK's. Heck, the well worn Champions that were in my bike when I got it performed better overall and masked the lean jetting that the NGK's were misfiring and performing poorly because of. I spent many hours troubleshooting the ignition system when I should have been re-jetting.

But if it weren't for how badly the NGK plugs behaved, I would not have started swapping jets in my carbs, so at least I can say something positive about them!

 

[Lou Ranger]

... It's just when you referred to ham-fisted gorilla mechanics, all I could think of was us ...
It's an interesting though wandering train of thought: bolts, anti-seize, now plug type. Have you ever tried those odd looking Bosch plugs with either 2 or 4 electrodes around a platinum centre electrode? Perhaps they will ignite the mixture as well as the Champions.
I must admit that I have had good luck with NGK. I inherited 2 from the PO and I have put on over 14,500 kms with them since I got it. They still perform like the first day, and have remained gapped correctly. Every once in a while I look at them and switch them between cylinders and they keep working the same. I have nothing to compare to though, so maybe the bike would run twice as well on something else, I just don't know.