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Head Bolts

>Subject: Re: Head bolts
>
>On Thu, 26 Sep, btoski@domain.elided (Bruce Toski) writes-
>
>...Shop suggests replacement to all customers with old bolts still in
>head.  Pull valve cover and replace ONE AT A TIME...
>
>My question, what is the strength rating (i.e. the number stamped on
>the head) of the recommended replacement head bolts.  I believe
>the head bolts on my '81 528i are stamped 10.8, which if memory
>serves correctly is 10,800 psi tensile strength.  All this talk of
>head bolt failure has me slightly paranoid, and wonder if I should
>change to higher strength bolts.
>
>Anyone...?
>
>Ryon
>'81 528i
>'95 VW Golf
- --------------------------------------------------------------------------
The factory head bolts are a grade 10.9 which is a 156,000psi tensile
strength.  This should be more than adequate.  The next grade up is 12.9
which is 176,000psi tensile strength.  These are available as allen cap
bolts...torx would be special order and presumably quite expensive.  The
head bolt set in 10.9 should be $20-25 for 14/bolt set.  SD
Steve D'Gerolamo c/o The Ultimate Garage,  Emerson, NJ  (201-262-0412)