TTAC regular VerbalKint asks:
1. Should (can) any type of lubricant (ever) be used on the treads of bolts being torqued to specification?
2. Have you seen this site? I thought it was pretty well done, how ‘bout you? I really liked their section on oil scams additives.
Sajeev answers:
Question 1: As an aside, check your car’s service manual: everything is torqued to spec. Or can be, if your OCD requires a certain ft·lb rating on your velvet-covered glovebox liner. When it comes to lubricants, I’ve used a dab of anti-seize on threads making their home in aluminum parts. And that’s about it. Unless a service manual says otherwise, don’t lubricate a bolt. If removal is your concern, marinate them in PB Blaster (or equivalent) a few minutes before you put a wrench on them. Delicious!
Question 2: I had not seen that website until now, and TTAC doesn’t go out of our way to recommend other sites.
But this time, why the heck not? The site is informative, easy to read and (given the learning curve of the subject matter) a fun read too. Remarking that “Amsoil [is] one of the biggest inadvertent offenders of the fake API symbol” is on par with something in an RF editorial. And that’s entertaining because it’s true.
[Send your technical queries to mehta@ttac.com]
For oil into, it’s hard to beat http://www.bobistheoilguy.com
To add: Usually, when adding anti-seize, the torque spec of the bolt changes…unless the manual states that the torque spec is for the bolt WITH anti-seize.
For instance, I believe in Subarus the torque spec for a spark plug w/ anti-seize applied is ~30% less than the torque spec for a spark plug w/o anti-seize.
Copaslip is literally the Nectar of the Gods.
At least the Gods Thor & Vulcan.
–chuck
So I read the carbible site…
Lotta good information, but that guy freely admits that some of his past claims were way off base and some of his current claims are way off base as well.
For instance, he strongly recommends against 0w20 (except for hybrid owners whose manuals recommend it) as it’s “way too thin!!”
However, that’s completely off-base. An oil’s viscosity is correlated to it’s film strength, but this isn’t a 1-to-1 thing.
There are 0w20 and even 0w10 oils with incredible film strengths and resistance to breakdown, that are good choices for many engines.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1483872&Board=3&fpart=all&gonew=1#UNREAD
There’s a link to a guy running Pennzoil Platinum 5w20 in his 5.7 liter charger for almost 10,000 miles at a time….the oil held up beautifully, and could’ve gone longer.
It’s all about the oil’s film strength. Sometimes, a thinner oil will perform better in certain applications than a thicker. Less viscous oils can get pumped faster, which allows greater heat dissipation and the benefits of faster oil refreshing.
Very application specific, and not good to make broad claims about.
I’ve had the same question concerning spark plug replacement. I’ve always thought that the use of thread lubricants dictate reducing applied torque, compared to dry installations.
BMW and Porsche service manuals make no mention of anti-seize products when installing plugs into aluminum heads.
In fact, Porsche recommends not to use anti-seize, saying something about preventing the plug from being properly grounded (who knew?).
… he strongly recommends against 0w20 (except for hybrid owners whose manuals recommend it) as it’s “way too thin!!”
That is enough to qualify the author as uninformed. The 0W portion of the rating refers to cold cranking ability, not the oil’s viscosity under normal running conditions. It is amazing how many people get that completely wrong.
There are 0w20 and even 0w10 oils with incredible film strengths and resistance to breakdown, that are good choices for many engines.
How does one determine which oils posses what film strength?
Back (waay back) in ’78 I used 0-20 Mobil1 in my then stock Scirocco. Result was scored camshaft lobes.
After many engine mods and a redline increase to 7200 RPM I used Castrol GTX oil. No further problems.
VerbalKint – The oils of the 70s, 80s, and even part of the 90s are FAR far different than those produced today. That website actually does a good job of something that.
An oil’s film strength is based upon a number of factors. The oil’s job is to prevent two pieces of metal from coming in contact with each other. Film strength is basically a term to denote how much the oil can take and still achieve that aim.
On the highest possible level, HTHS (high temperature/high shear) is a rating system that can provide a rough indication of pure film strength of an oil under stress.
NOACK Volatility helps to indicate how stable the oil is (i.e. likely to change under stress)
There are all sorts of characteristics that go into this stuff….viscosity helps correlate not just to strength, but oil flow. The more an oil flows, the more heat transfer there will be away from the “hot spots” thereby helping keep the engine cool. Further, the more an oil flows the more you can avoid overstressing an oil.
That’s a broad stroke, since sometimes you want a certain level of flow for oil pressure and other aspects.
Anyway, I’m rambling here….not all oils are created equal and viscosity is, at best, a very rough guide.
Joe
I’ve been to that site before, and some of the other articles are quite good. He covers more than oil.
Getting back to the original question, I’d have to say I disagree somewhat with Sajeev’s advice. I use antiseize on almost all threaded fasteners when reassembling. (The only exception I can think of is wheel studs.) I probably won’t have to disassemble the same component to fix it again for years, but I still want it to come apart at that time!
Dissimilar metals (eg: spark plugs and accessory bolts in aluminum heads) should always be assembled with neverseize. I’ve read that some sparkplugs come with a neverseize coating applied at the factory, so this is not required. (I’d probably still put some on.)
In my experience, the torque specs for internal engine parts assume they are coated with neverseize or #30 motor oil. ARP provides their own torque specs for their fasteners, and they specify the use of their own brand of moly lube.
The bolts are electrically torqued with a computer controller.
The engineering side: The real measure of whether a bolt is properly fastened is thread engagement, stretch and therfore clamping force. A Torque spec is a reasonable approximation of how much static friction the bolt has at the desired clamping force. I have a feeling the factory machine putting any bolt in uses more than just torque measurement, but I don’t work in the industry so I don’t know.
Also you have to consider that sometimes the torque spec is based on a bolt not being lubricated, and that if it is lubricated, there will not be enough friction to keep the bolt from backing out. In this same way some bolts with light clamping force and hence low friction will have loctite specified for installation.
Practical experience: I have only ever worried about lubrication on possibly sensetive stuff like head bolts, intake/exhasut manifolds, always heed the service manual procedure. On other bolts, putting a little anti-seize shouldn’t be a problem. That’s usualy better than rusty/dirty threads that mess with the torque spec just the same. You do have to use your head though when you encounter a bolt that might back out with too much lube…what was I talking about?
Here is probably more info on fasteners than anyone wants. http://www.boltscience.com/index.htm
re: the bible
there are as many opinions on motor oil as there are pages on the internet
FWIW I ran 0W20 (which the bible says “Don’t ever drive with these oils in the engine – it won’t last.”) in an old Saturn with 130,000 miles and it’s running just fine.
re: bobistheoilguy
agree there are some smart knowledgeable folks over there, also some pimping for multilevel marketers (aka Amsoil). you almost need to be an expert to sort the good from the bad
indi500fan: yeah, I just automatically ignore any and all Amsoil-related comments, it tends to improve the level of discourse there :)
Hurls,
Been using AMSOIL 0w30 in my 2006 Civic SI for about 45k miles now….a total of 3 oil changes. Backed by independent analysis of the used oil.
Some of their stuff is worth the hype. Some of it is even a good value :)
Joe O,
I believe it… truly I do (personally caught up in the GC hype on BITOG). Just that the “distributors” on the site are a bit over the top :)
Meh, I only use a torque wrench for bearing caps and head bolts. I rarely break stuff or have it fall off. As for oil viscosity, use what the maker specs. Thin oil is good for heat conducting and reducing drag. And for satisfying CAFE.
The latest oil related outrage foisted on us by CAFE is eliminating the additive ZDDP from SM spec oil. This was to save cats from phosphorus contamination. My 350kmile 528e passes NOx specs and it has had a steady diet of 1600 ppm of ZDDP enriched 20w50 for 20 years. The cat is original and so is the engine Guys have had to add lash cups to the valve train to counter wear from using thinner oils with little or no ZDDP in them. I’ll stick to specc’ed oil. I buy SL or add stuff rich in ZDDP. This isnt supposed to a problem with modern valve trains, but it is an issue with classic car engines.
Meh, I only use a torque wrench for bearing caps and head bolts. I rarely break stuff or have it fall off. As for oil viscosity, use what the maker specs. Thin oil is good for heat conducting and reducing drag. And for satisfying CAFE.
The latest oil related outrage foisted on us by CAFE is eliminating the additive ZDDP from SM spec oil. This was to save cats from phosphorus contamination. My 350kmile 528e passes NOx specs and it has had a steady diet of 1600 ppm of ZDDP enriched 20w50 for 20 years. The cat is original and so is the engine Guys have had to add lash cups to the valve train to counter wear from using thinner oils with little or no ZDDP in them. I’ll stick to specc’ed oil. I buy SL or add stuff rich in ZDDP. This isnt supposed to be a problem with modern valve trains, but it is an issue with classic car engines.
IMHO another good TTAC article. Yes, The Oil Bible site has a lot of interesting info!
There are a few oil additives out there that were created by true oil chemists, and focus on seal protection, oxidation prevention, and neutralization of blow-by based acids. These have actual test results, and very few testimonials.
But it’s good the FTC found an extraordinary large number of fakers. That’s main reason there are many less oil additives advertised these days.
Wrt torquing, sounds like good idea to check with Mfr. as to how adding corrosion prevention might affect tightening.
If memory serves, biggest problem is with dis-similar metals, which can weld themselves together from electro-galvanic corrosion.
“which can weld themselves together from electro-galvanic corrosion.”
Honda has that problem with crank pulley bolts requiring 300 ft lbs to break. Honda recommends oil on the threads and bolt face.
The Engine Oil Bible misspells polyalfaolefin on the homepage. I guess everyone with an IP address is an expert these days!
For steel on steel, I use anti-seize on rusty threads where the bolt or nut will not turn easily without it. The anti-seize simply reduces the friction to that of a new, dry thread.
I would never torque a dry aluminum (or titanium) thread, unless there were specific instructions not to. I spent too long working as a mechanic in a bicycle shop (where most bolts thread into aluminum parts) to leave those dry!