torque for plastic valve cover?

[thejum57]

I am being lazy, I could look this up, but would anyone know off hand what the torque would be for a plastic valve cover on a 2.5l Comanche??  I called the parts store who "loans' tools, and heasked if I needed one for inch lbs. or foot lbs., I said inch....I snapped my original with a socket wrench so I figured there is not much tolerance. Got a new cover, grommets, oil cap, gasket, and will be getting new hoses for pcv, and the other "thing". Going to tighten this baby up, leaking a ton. I probly already paid for a steel cover, installation, and a few oil changes so far with the leaking  

 

Thanx for any input

 

Jim

 

[yxmj]

The actual rating is in inch pounds...and yes you are being lazy....google it.....

That being said the more important technique is righting it down equality... like you torque down a wheel.....google that too....I like to do mine in the same pattern as you tighten down head bolts...(google that)....finger tight first....then just a nut driver...then a small 1/4" ratchet to snug it up.....like putting a spark plug in.....sometimes that famous rear valve cover leak......is just because the back ones are harder to get at and get tightened last.....IMHO

[Pete M]

the proper technique is to throw it away and install a later model metal one.   

[thejum57]

Well, did look this up and found this site;

https://www.extremeterrain.com/wrangler-yj-engine-torque-specs.html

The reason I was being "lazy"....my words, was because the all knowing internet gives you lot's of non- info, and a run around. You guys usually just give straight up info. 

I do know most of the "look it up" stuff, just needed the torque specs. 

Thanks guys!  

[Pete M]

not sure anyone would know that particular thing off the top of their head.    been surprised before though   (I know I'd have to look it up)

 

but I do know that the metal one is superior.    

[thejum57]

No disrespect meant Pete! Just that most of you guys do seem to pull up info out of the air. I know the metal one is the bomb, but my truck needs LOTS of stuff, one income family, daily driver...uup! Trying to fix stuff one by one. Keep up the good work. Awesome site.  Thanks again

 

[thejum57]

Found a really good site for all torques, could be put in this clubs database?

http://www.torkspec.com/torkspecme.aspx?KI=69-2.5L-150ci-S4

 

 

[Pete M]

done.   

[Eagle]

52 minutes ago, thejum57 said:

Found a really good site for all torques, could be put in this clubs database?

http://www.torkspec.com/torkspecme.aspx?KI=69-2.5L-150ci-S4

 

 

 

Probably doesn't apply to the plastic valve cover but, since we're talking about torque values -- remember that most torque specs are based on "clean, dry" threads. If you use anti-seize (as I do on everything), the torque has to be reduced. The percentage of reduction depends on the diameter and thread pitch -- a general rule-of-thumb I have always followed is 20 percent, but I just found a source that says 25 percent:

http://www.antiseize.com/PDFs/torque_specifications.pdf

 

 

 

[gogmorgo]

^^^This.

There's one bolt, I think between the case halves on a Honda CBR600RR block, that for whatever reason likes to collect oil. And unless we've made damn certain to clear everything out of it, brake clean soak then blasting it out with compressed air for a few minutes, lather rinse repeat a few times, we'd neck and twist it off before getting anywhere close to the torque spec, which was something pathetic like 12 in-lbs... I'll admit it wasn't a big bolt but we broke the third one off before hitting 6.

Took us a few times getting the brand new bolt from Honda before we figured out it wasn't just a bunch of defective bolts. Just having the thin film of brake cleaner on it was enough lube to get it to neck.

[Eagle]

Basically anything other than "clean, dry" threads requires a reduction. For things that may loosen from vibration, I often used thread locker (a.k.a. Loctite). That also requires a reduction in torque, although some sources suggest not reducing by 20% to 25% with thread locker.

 

The deal is that bolts hold thing together by stretching slightly, but within the "elastic limit" of the steel. Just like the tension when you stretch a rubber band, the tension created when you stretch a bolt generates the clamping force that holds the parts together. Engineers decide how much clamping force they need, and specify the torque needed to generate that much force. Turning a threaded bolt is like pushing a weight up an inclined ramp. Put some oil or grease on the bottom of the weight, and it slides up easier so you need less force to push the same weight. That's torque -- with lubricated threads, you need less applied torque to generate the same stretch in the bolt. And, as gogmorgo mentioned -- especially with small bolts, if you exceed the elastic limit of the bolt -- it necks down (stretches beyond the elastic limit) and breaks.

 

For what it's worth, by the way, before posting my advisory above I did a Google search to try to find authoritative sources to steer you guys to. What I found was mostly discussion forums, and a lot of self-proclaimed "experts" who pooh-poohed the notion of reducing torque when using anti-seize.  (I also found some who pooh-poohed the notion of using anti-seize at all -- are you kidding me?)  Just remember -- unless otherwise stipulated, published torque values are for "clean, dry" threads.

[DirtyComanche]

Self proclaimed expert.

 

Most torques given for engine assembly are with the threads lubed with oil.  It's standard practice, as no engine components are assembled dry.  Anti-seize would require a higher torque, if anything, than lubed with engine oil.

 

If you've spent any time behind a wrench you should be able to feel the bolt stretch when it hits torque.  This is elastic deformation, there's a brief period (15-30 degrees) where you can turn the bolt without the required torque to do so increasing.  After that the torque increases, then it decreased, this is plastic deformation at that point, and you'd better f'ing stop or it will break off or the threads will come out.

 

Snap-On used to sell a 'magic' torque wrench.  It worked on this concept.  They were great, but people used them when they shouldn't have...

 

No, I don't trust my arm or elbow, I use a real torque wrench.  I do not decrease torque values for applying anti-seize, there's enough spread on the torque range for a fastener that regardless if it was a dry or wet torque that was spec'd you will get away with it, UNLESS it is in some special cases with either low grade/super elastic bolts, or threading into soft metal castings, or you've got bolts/nuts with threads that could only be considered a class O fit.   In those cases you have to be careful, as always THINK before you do something.  Examples would be if you're threading into straight aluminum, or a poor grey iron casting with minimal engagement.

 

Too tight is always better than too loose.  An overtightened bolt will live, and undertightened one will either back out or break off, save for rare instances that mostly don't apply in automotive use.

 

If you take your truck to a SAE certified mechanic, the chances are he will tighten everything with the impact set to 11.  He does this all day.  Either the bolt breaks off then, or it is fine.  Is it right?  Hell no, but it works.

[Eagle]

2 hours ago, DirtyComanche said:

Self proclaimed expert.

 

Most torques given for engine assembly are with the threads lubed with oil.  It's standard practice, as no engine components are assembled dry.  Anti-seize would require a higher torque, if anything, than lubed with engine oil.

 

Sorry, but you're wrong. From page 8 of the 1994 Jeep FSM for Cherokee and Wrangler:

 

It is important to be aware that the torque values listed in the chart [on page 9] are based on clean and dry bolt threads. Reduce the torque value by 10 percent when the bolt threads are lubricated with engine oil and by 20 percent when new, plated bolts are being tightened.

 

I'm pretty certain you'll find basically the same statement in all the factory service manuals.

[75sv1]

I read somewhere to reduce the torque value if using anti-sieze. Also, to calculate it if using an extension. ARP on their rod bolts prefer to use a micrometer measurement as to the stretch of the bolt. Steel is elastic to an extent. It stretches, it spring. That it until you exceed it limits. Then as mentioned above, it don't spring back.