Bearing Caps, Locktite?

[kiznook]

Should I use blue threadlock on the main bearing and connecting rod hardware? Will it mess with the torque? Do these really only need 36-40 ft/lbs?

 

Any help is appreciated!

[datzenmike]

For stock applications you won't need it. You hear of people spinning a rod or main bearing but the fasteners never fall off. No harm if you do use it.

 

L20B main bearing cap bolts and rod cap bolts are 33 to 40 ft. lbs.

[kiznook]

Thanks Mike, I knew you'd have the answer! And that's good news, because it means I don't have to tear into it again.

[LenRobertson]

A vaguely related question re flywheel bolts - I know some use Loctite on these and some say don't bother. I'm doing a stock L20b for street use, no autocross or such, so I'm inclined to skip the Loctite. However, I've read that dry threads, oiled threads, or anti-seize coated threads actually reach different tightness when torqued to the same reading on the torque wrench. Does this sound correct? Which should I do for flywheel bolts when torquing to factory spec? Or is this one of those things that doesn't make any difference in the real world?

 

Len

[datzenmike]

The less friction on the threads the truer the torque value. A rusty bolt or a lightly oiled bolt will both torque to 100 ft.lbs. but the rusty thread bolt won't screw in as far and clamp down as hard as the oily thread bolt.

 

I had an old motor out for some months and the crank threads got rusty. I saw this and said fuck it and cranked the flywheel bolts down to 100ft lbs and assembled everything. Six months later I'm driving along in town and the motor revs up and no drive force. The idle was really shaky. I shut it off and tried to restart but the motor wouldn't move even though the starter was. Yup, the bolts took their time but finally sheared off. (I used the starter with tranny in third gear to get me a few blocks to park it) Bolts were tight, flywheel was not.

[zed]

I use locktite on pretty much everything except head bolts - cos I'm an amateur, figure I need the insurance. Also, I rather use less force on a bolt than more.

[dimedriver]

Carrol Smith wrote about this in "Engineer to Win".

http://books.google.com/books?id=5a8937Pc6uEC&pg=PA155&lpg=PA155&dq=carroll+smith+threadlocker&source=bl&ots=QzKzoDue6p&sig=fG5TsxuCqCNL2K2iF0smXyxP560&hl=en&ei=wgG4SsjGNIWgsgOmyvTRDA&sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=&f=false

That should get to the loc-tite page in the book.

Page #153 in the older edition with the black stealth looking car on the front.

 

He also writes about torquing fasteners. He claims that you should at least put some type of oil on them before torquing. Be it 30 weight or what have you. This is unless your using loc-tite. You should clean the fastener and whole with some thing like brake cleaner be fore applying the loc-tite.

 

I also like the "Keeping It All Together." article by Joseph C. Dille.

http://home.jtan.com/~joe/KIAT/kiat_1.htm

Its nice and covers mostly metric stuff.

 

-Avery