1.9 AAZ Crank Bolt over torque

[dieselsmoke]

I installed my crank bolt the other night and in the bently manual it says to tighten the bolt to 66ft/pounds plus 1/4 turn. It also says to put some oil on the threads and shoulder of the bolt. Instead of using oil I used red locktite on the threads (none on the shoulder) and tightened it to the 66 ft/pounds. I used my 2 foot long 3/4 inch breaker bar and did the 1/4 turn no problem. I thought that it went too easy since I have read that it is supposed to be hard to tighten the 1/4 turn so I did an additional 1/8 of a turn. After doing that I am wondering now if I could have damaged the bolt or can these bolts take alot more?? I got the new style 12 point 19mm bolt. Thanks

[burn_your_money]

When we were rebuilding Giles' engine we went through 2 crank bolts because after we did the first one we were like "no, that was too easy" and took it out and tried again. It was just as easy the second time around.

Since you didn't follow the directions for using oil the torque specs are almost irrelevant unfortunately.

[dieselsmoke]

True, but with that locktite on it I don't have to worry about it going anywhere.

[maxfax]

ALthough maybe not as good as oil, I would think the loctite would still lubricate things to a point before it hardens..

[commuter boy]

VW was using SOMETHING on the threads besides oil.  I just pulled an original crankbolt
this weekend and it was coated with a thick threadlocker type hardened goo.

That was out of a 1997 AAZ, probably after the time they realized that there was
a problem.  Maybe it was a stopgap measure before they went to the TDI crank
style?

I don't know if a thin loctite would change the torque spec that much more than
an oil would.  The red threadlocker I used was pretty thin......

[burn_your_money]

True, but with that locktite on it I don't have to worry about it going anywhere.

You don't have to worry about the threads going anywhere, but the head can still snap off. I have one of those engines in my collection at the moment....

[dieselsmoke]

So would an extra 1/8 of a turn be enough to damage this kind of crank bolt or can they take even more than that before the head snaps off?? I guess I could always take this bolt out and put in a new one and torque it down again. I hope the red loctite won't be too hard to break.

[clbanman]

If you look at Loctite's K-values at the bottom of the pic, you can see some have better lubricity than oil, some worse, so the effect of the Loctite on the clamping force varies depending on which product you used.

[dieselsmoke]

Very interesting, thanks for posting that.

For anyone who is interested, I have two bently manuals. One is for the 93-99 vws  and the other is for the 85-92 vws. I looked up how you are supposed to torque the crankshaft bolts down and in the 93-99 bently book it says 66ft pounds plus 1/4 of a turn (90 degrees) for the 12 sided bolt. I then looked in the 85-92 book and for the same 12 sided bolt it says 66 ft pounds plus 1/2 a turn (180 degrees). So what is the right answer? I guess as long as you have it between 1/4 - 1/2 a turn you should be ok.