Jan wrote,
>Jay,
> I still have my lever-beam torque wrench, but it's hard to read
while
>one is using it. I bought my clicker wrench back in the 70's when it was
>the latest thing on the market and I was told then, it was more accurate
>(because you didn't have to read the scale). I guess the headbolt
>threads should be cleaned out with a tap too. But, now I read on the new
>engines, one should not use a tap to clean out the threads. Also, when
>one is renewing the head gasket on the new cars, the head bolts need to
>be replaced too. My god how things change.
>Have a nice weekend
>Jan
The nuts shouldnt need to be chased, unless the have been damaged,overtorqed
or are a cheap grade. The nuts could be checked with a go/no-go thread
checker to verify that the threads are in spec, or have not been stretched.
The reason that the opinions on the head bolt replacements has changed
in recont years is because the OEMs have statistical data that shows
stress based failures of reused fasteners. This due to materials
quality, and defects.
High quality (aerospace) fasteners made from various materials such as
8740 and inconel, solve many of these issues, but cost more than the
fasteners used in general automotive applications.
These fasteners can be reused many times, provided that the stretch of
the fastener is monitered, and the yield not exceeded.
For more info, check this out from ARP.
http://www.arp-totalseal.com/Alloy%20Material%20Page.htm#http://www.arp-tota
lseal.com
Jarrid Gross
This archive was generated by hypermail 2b30 : Tue Sep 05 2000 - 10:49:09 CDT