Michael Maskalans <dml@tepidcola.com> wrote:
: On Jan 3, 2005, at 16:23, Eric Hufstedler wrote:
:> Aren't some torque specs (like head bolts) listed with oil in mind?
:> Not
:> trying to argue, just sort it out.
: not unless that is clearly stated - which I have never seen. torque
: specs are always with clean, dry threads (which you'll often see
: explicitly stated)
In the interests of broadening one's horizons :-) here are a
few examples:
HPBooks "How to Rebuild Small-Block Mopar Engines", page 134:
"Coat the head-bolt threads and the bolt-head underside with
anti-seize compound to prevent seizing and ensure accurate torquing."
HPBooks "How to Rebuild Big-Block Mopar Engines", page 132:
(Referring to the cylinder head bolts) "Coat the threads and the
areas beneath the bolt head with anti-seize compound."
Edelbrock Mopar B/RB aluminum cylinder head installation instructions, page 3:
"Apply oil or suitable thread lubricant to head bolt threads and
the underside of bolt heads and washers"
Although I couldn't find the instructions that came with the ARP bolts
I used on the Cuda, as I recall, they recommended using a lubricant also.
(I belive ARP sells their own brand of lubricant to be used for this
purpose.)
I checked my '96 FSM but it didn't say anything about lubricant
on head bolts with the exception of the 2.5L engine, where one of
the bolts receives some sealant (perhaps it goes into a water jacket).
They are careful to say that only that one bolt should be coated,
and that particular bolt got a 100 lb-ft torque instead of the 110 lb-ft
that the rest received. They don't say one way or the other for
the 3.9 or 5.2 motors though.
Here's a link which basically says that fasterners should *always* be
torqued with a thin film of lubrication in order to get the best
accuracy (they say dry threads can bind and throw off the readings):
http://www.mustangmonthly.com/techarticles/39446/index6.html
Here's a post from a guy who seems to know what he's talking about in
this area: http://yarchive.net/car/bolt_torques.html
Based on my limited research in this realm, the conclusion I have
come to is that it seems the most accurate way to obtain torque readings
is by using a lubricant, which will help to eliminate much of the slop
factor which friction can cause, due to dry threads. However, this is
something which the manufacturer should have planned for from the
beginning by publishing "wet" torque specs. I guess it just comes
down to "when all else fails, read the directions". :-) If the
instructions that came with a product say to torque them wet or dry,
do it the way they say. If they don't specify, use your best judgement.
It would seem that applying a *very thin* film of lubricant probably
won't hurt anything. If using such a lubricant, it would probably be a
good idea to use a "thread lubricant" specifically designed for this
purpose. As I stated above, I believe ARP makes one, there might be
generic brands available also.
--
-Jon-
.-- Jon Steiger ---- jon@dakota-truck.net or jon@jonsteiger.com --.
| 1970 Barracuda - 1990 Dakota 'vert - 1992 Ram 4x4 - 1996 Dakota |
| 1996 Intruder 1400 - 1996 Kolb FireFly - 2001 Ram QC 3500 CTD |
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