[DeTomaso] Another header question: bolts- Header Bolts and Aluminum Heads

Mon Dec 29 02:34:02 EST 2008

Rich et al:

For what it's worth, my manuals all recommend using a premium anti-seize on 
steel bolts, in aluminum heads. The professional knowledge all points to the 
fact that galling of the aluminum threads from dissimilar metals is what 
destroys threads in aluminum heads. Stainless bolts are probably the worst 
for galling, as it has the "roughest" metal surfaces. By using healthy 
amounts of quality anti-seize (specifically recommended for your bolt metal, 
in aluminum threads), the galling should be prevented. At the same time, 
paying strict attention to the torque requirements, and the tightening 
patterns is also a requirement for aluminum thread longevity.

There are more than 4 major types of "anti-seize" available now. They all 
differ in significant ways. The corrosion resistance, the temperature range 
(one can handle 2987°F, and just for comparison, aluminum melts at 1600°F, 
and steel burns at 2900°F), and so forth. Then there's the grades: Nuclear, 
Aircraft, High Temperature, Food Grade, Premium, Marine, and more.  One 
series varies by metal flake used; copper, nickel, lead, or aluminum (Nickel 
is excellent for stainless steels, and aluminum alloys). One is much better 
for stainless plus dissimilar metals, while another is more suited for 
standard steels. You'll definitely need to read the small print before you 
decide what you really need.

Personally I use Aircraft Grade Water-Resistant Zinc Antiseize thread 
lubricant.... at $21 for an 8 ounce can.... as it is specifically 
recommended for aluminum applications. It meets mil-spec CID-A-A-59313, and 
has a temp range of -65°F to 800°F.

If you want to see a decent range of anti-seize products, go to 
www.mcmaster.com and look at Catalog Page 2114. Or else, simply enter 
"anti-seize" in the "Find Products" text box.

I guarantee you'll be amazed, this comes under the heading "I had NO 
idea.....".

Chris

Chris Difani
'73 L #5829 "LITNNG"
The Electric Pantera
Sacramento, CA
Email: cdifani at pacbell.net

_____________________________________________
----- Original Message ----- 
From: "Rich" <hoppe1 at cox.net>
To: <MikeLDrew at aol.com>; <cengles at cox.net>; <detomaso at realbig.com>
Sent: Sunday, December 28, 2008 3:56 PM
Subject: Re: [DeTomaso] Another header question: bolts

> On the subject  of header bolts.    Do you do anything different for
> aluminum heads?  Studs?
> ----- Original Message ----- 
> From: <MikeLDrew at aol.com>
> To: <cengles at cox.net>; <detomaso at realbig.com>
> Sent: Sunday, December 28, 2008 4:39 PM
> Subject: Re: [DeTomaso] Another header question: bolts
>
>
>
> In a message dated 12/28/08 15 07 26, cengles at cox.net writes:
>
>
>> On the topic of header bolts, does anyone have an opinion
>> about either Percy's Split Lock header bolts or the Stage 8 Locking 
>> header
>> bolts?
>>
>
> I've seen the Stage 8 bolts, and they seem pretty neat, although I think
> they
> require a bit too much fiddling around, and of course since you need to
> tighten header bolts after the engine has been through a couple of heat
> cycles,
> that requires a lot more work.
>
> Personally, I am advocate of ARP small-head header bolts.   These are
> special
> bolts made with a smaller-than-normal 5/16" head (rather than the more
> conventional 3/8").   You wouldn't think that a lousy sixteenth of an inch
> would
> make a difference, but brother, I'm here to tell you that it does.   Some
> headers
> have the pipes exiting the flange at a slight angle, which can sometimes
> interfere with your ability to place a wrench on the bolt head.   What
> follows is
> an agonizing ritual of turning the bolt 1/32nd of a turn at a time,
> constantly
> having to flip the wrench to get even a slight purchase on the bolt head.
>
> These smaller heads make short work of this.   The additional clearance 
> can
> be enough to let you get a box-end wrench in there, or a socket--either 
> one
> makes a huge difference.
>
> And they are ARP quality, nothing to sneeze at there.   Once the engine 
> has
> gone through a couple of heat cycles, you'll need to go back and snug them
> up
> again, and then they should be good to go forever.
>
> Here's a photo from the Summit website:
>
> http://tinyurl.com/8dokeh
>
> Summit doesn't specifically list these bolts as 'small head', so I was 
> only
> able to find them by first looking in my ARP bolt catalog for the part
> number,
> then typing that number in the 'search' box on the Summit website.
>
> These bolts are available in two lengths; either .750" or 1.00".   My Euro
> GTS headers (and the headers on my other cars as well) have fairly thick
> flanges
> so I always go for the longer bolts.
>
> They are available in either 6- or 12-point, black oxide or stainless.
>
> Part numbers:
>
> Bolt kit, 5/16" wrench, length .750
>
> Black oxide 6-point: 100-1108
> Black oxide 12-point: 100-1208
> Stainless 6-point: 400-1108
> Stainless 12-point: 400-1208
>
> Bolt kit, 5/16" wrench, length 1.000
> Black oxide, 6-point: 100-1110
> Black oxide 12-point: 100-1210
> Stainless 6-point: 400-1110
> Stainless 12-point:   400-1210
>
> Entering any of those part numbers in the 'search' box will bring them 
> right
> up on the Summit website.   Cost is $24.69 for the black oxide, 1-inch
> six-point bolts.   Plus Summit charges a flat handling charge, which I
> believe is
> $11.95 now?
>
> I have actually found that it's cheaper to buy ARP bolts directly from the
> factory.   If you call them up and tell them what you need, they just pop
> 'em in
> the mail to you, saving on shipping, and the retail price from them is
> usually about the same or even a bit less?
>
> Contact info can be had on the 'contact us' link on the ARP website:
> http://www.arp-bolts.com/
>
> Cheers!
>
> Mike
>
>
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