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Posted: Fri Jul 06, 2007 1:34 pm
by A1-2-A3
The idea of torque-turn was to eliminate human error. What if this guys threads are dirty and the next are clean and lubed. Will they really be the same torque. Adding a torque-turn makes every assembley more uniform.

Posted: Fri Jul 06, 2007 2:11 pm
by tylernt
Also, a bolt stretched past its plastic limit will have more clamping force to keep the head gasket from blowing.

Posted: Fri Oct 26, 2007 10:23 pm
by bertcarrier
The 11mm stretch bolts did not hold worth a 'dern. I blew the head gasket after 100 miles. I ended up burning up the head. :evil: I am skeptical about the holding power of stretch bolts in the 11mm engines.

Posted: Fri Oct 26, 2007 10:43 pm
by Vdub-bub
I just replaced the head gasket on my 92 Jetta TD, made sure to apply anti-seize compound to the threads as well as both sides of the washer, my 1000 mile retorque went very smoothly, none of that horrible "CRACK, then turn way too easy" stuff, just a nice, easy and smooth 90 degree turn.

Posted: Sat Oct 27, 2007 9:51 am
by Wolfsbur
On gasser VWs, I've been using the TTY factory head bolts since 1989--never used lube, of any kind, on the threads. Only had problems with come-backs with the early jobs, when I wasn't as carefull checking the head for flatness and making sure the area around where the HG fire-rings bite, on both the block and head, were not pitted/scored/cracked.

I chase the the threads, then shoot some carb cleaner down the holes, then after a few minutes, shoot shop air down the hole while holding a rag around the air nozzle to catch the crud shooting out (in a pinch, you can take the fill valve (shrader/presta) off the end of a bicycle pump and use that to clean out the holes).

If I install a head stud set (Raceware/APR) I follow the directions. The last Raceware set I did, required their lube, or 30W non-detergent oil on the threads, torque, run engine to temp and re-torque.

A problem with lubing the threads on the factory TTY bolts -- clamping force may not be the same with the threads more freely turning than what was intended using the published proceedures. We would have the wrench we used for head bolts/studs re-calibrated every 6 months, and if someone dropped it, sooner. (I dropped it twice--in a two week period--DOH!)

I'm trying to remember a bad head bolt causing a failure in any of the jobs I did--but just now I can't recall any. In '94 the shop did near 30 HG R&Rs. With the threads chased, and no wetness down the bolt bores to compress and bleed up the threads, the bolts turn very smoothly. Still takes some force to TTY, but no loud cracking, or catching.

VR heads are the biggest pain, of all the VAGs I've done.

Posted: Sat Oct 27, 2007 10:00 am
by tylernt
I used anti-seize and I still got a tiny bit of cracking on the initial tightening and a lot of cracking on about half the bolts during the re-torque. I hate head bolts, going to use studs next time for sure.

Maybe my problem was that I used oil on the bolt heads and washers instead of anti-seize.