[s-cars] Replacing Spark Plugs after Compression Test

[Vincent Frégeac]

It can simply be that a 25-30lb.ft torque is enough to get this spring
effect on a used crush washer when 22lb.ft is just enough for a new one.

I don't know enough about the physics of washers to answer the last
question. If we've never seen a spring washer or a lock washer on a
plug, whatever the car, there should be a good reason, like you also
want to get the plugs out if needed.



Vincent.

-----Message d'origine-----
De : Dave Forgie [mailto:forgied at ae.ca] 
Envoyé : 3 févr. 2004 19:18
À : s-car-list at audifans.com; vfregeac at sympatico.ca
Objet : Re: RE : [s-cars] Replacing Spark Plugs after Compression Test

Vincent:  I think you could be right about the torque setting.  I know
what you mean about feel.  I have used my old beam-type torque wrench as
more as a guide (no click and quit like the spring loaded torque
wrenches).  As a result, I know that I am about 25 to 30 lb ft when I
actually decide to stop.  However, I still say the crush washers are
there for a purpose: To provide a spring effect that drives the threads
on the plug upwards against the threads on the head and, thereby, adding
more friction surface than provided by a totally flattened crush washer
contacting the head.  But then what do I think the compression cycle is
doing to the plug threads?  Not driving them up?  Why isn't there a more
positive way to lock the plugs into the head??

Dave F.

>>> Vincent Frégeac <vfregeac at sympatico.ca> 02/03/04 04:10PM >>>
My plugs have been in and out many times. No loose plugs. I've never
used my torque-wrench either. I just torque them by feeling, as I've
done on all previous cars. So, I'm wondering: If people who use the
22lb.ft spec have loose plugs issues, could it means 22 lb.ft is a bit
low. I think this weekend I will check what my feeling reads on my
torque wrench to see how it compares to the 22lb.ft spec.



Vincent.

-----Message d'origine-----
De : s-car-list-bounces at audifans.com 
[mailto:s-car-list-bounces at audifans.com] De la part de Dave Forgie
Envoyé : 3 févr. 2004 16:25
À : s-car-list at audifans.com 
Objet : [s-cars] Replacing Spark Plugs after Compression Test

Richard (and others):  The washer on the F5PDOR plug is a crush washer.
AFAIK, once it is compressed, i.e. after you put the plugs in an torque
them to 22 lb ft, it can't be expected to its job if you remove the plug
and then put it back in.  I personally contend that some of the problems
with plugs being blown out of their holes is because people back their
plugs out to retorque them.  I suggest that retorquing should be a
tighten only exercise and that if the plugs come out for any reason, new
plugs (with new crush washers) should replace them.  And no, the crush
washers are typically not available separately.

In my humble opinion,

Dave F.

_______________________________________________
S-CAR-List mailing list
S-CAR-List at audifans.com 
http://www.audifans.com/mailman/listinfo/s-car-list 

---
Incoming mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.576 / Virus Database: 365 - Release Date: 30/01/04
 

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.576 / Virus Database: 365 - Release Date: 30/01/04
 



---
Incoming mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.576 / Virus Database: 365 - Release Date: 30/01/04
 

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.576 / Virus Database: 365 - Release Date: 30/01/04