Proper torque settings for 12.9 grade main bolts?

[Thuppu]

So, the stock main bolts(10.9 grade) torque specs are 48ft/lbs. ARP mains 65ft/lbs, but this can bend the main caps and press the clearance to zero.

So I suppose 12.9 grade bolts should be something between these? What would be the ideal sweetspot?

[Laaf]

I torqued my main ARP studs to 81 Nm / 60 ft/lbs as this instruction; http://arpinstructions.com/instructions/204-5404.pdf
No problems with clearances what so ever and the crankshaft spun easy so I didn't bother with line honing. I found this cheap unused on the swedish Audi forum so that's the only reason I bought them, otherwise I would just have used the OEM ones.

[Error404]

I found the ARPs squashed the caps by only approx 0.01mm so leaves plenty of clearance

[Thuppu]

Ok, great to hear guys. I guess ARP's are stronger than 12.9 grade bolts, so what would you use for torque, 55ft/lbs?

[AndyP]

Ok, great to hear guys. I guess ARP's are stronger than 12.9 grade bolts, so what would you use for torque, 55ft/lbs?

You rebuilding your engine again??

[Thuppu]

No, not yet. This is an other engine I can throw in and drive the winter. Have to take apart the "main" engine an try to figure out why it's eating oil.

[prj]

Eating is the correct word indeed. I think it was about 1:5 ratio of oil to fuel consumption last time

[Laaf]

Ok, great to hear guys. I guess ARP's are stronger than 12.9 grade bolts, so what would you use for torque, 55ft/lbs?

Had a look around on Nordicaudi and it was mentioned 65-70 Nm for 12.9 bolts used with a girdle. Guess he used a kit from CP-Service where most of the swedes source their 2.2t tuning parts

[pasbogdan]

So, the stock main bolts(10.9 grade) torque specs are 48ft/lbs. ARP mains 65ft/lbs, but this can bend the main caps and press the clearance to zero.

So I suppose 12.9 grade bolts should be something between these? What would be the ideal sweetspot?

Try them,torque and use a internal gauge.First measure with them half torque or less to get sure that they are perfect round.They usualy are not

[driftin jo]

Whatever bolts you use they need to be torqued to achieve the correct amount of pre load. This is done by measuring how much they stretch. Im talking about elastic stretch here not plastic deformation that you have with a 'stretch bolt'.
The main bolts need correct pre load as they are subjected to cyclic loading. If there is insufficient pre load then work hardening and eventual failure can happen. I would PM jp as he will be able to tell you how much stretch is right.

[AndyP]

No, not yet. This is an other engine I can throw in a drive the winter. Have to take apart the "main" engine an try to figure out why it's eating oil.

Me too, see here

http://www.s2forum.com/forum/showthr...light=high+oil

How much is yours using and what do you think is the cause??

PM me or reply on my thread if you don't want to clutter this one!

[V6quattro]

I torqued my main ARP studs to 81 Nm / 60 ft/lbs as this instruction; http://arpinstructions.com/instructions/204-5404.pdf
No problems with clearances what so ever and the crankshaft spun easy so I didn't bother with line honing. I found this cheap unused on the swedish Audi forum so that's the only reason I bought them, otherwise I would just have used the OEM ones.

I also torqued my ARP mainstuds to 81Nm and the crank didn't spin at all! So i have line honed mine. Strange

[Thuppu]

Me too, see here

http://www.s2forum.com/forum/showthr...light=high+oil

How much is yours using and what do you think is the cause??

PM me or reply on my thread if you don't want to clutter this one!

My uses !!!SHITLOADS!!! and it's coming past the rings. Can't think of nothing more than wrong(too big) piston to wall clearance combined with low tension oil rings.

[Dybro]

So, the stock main bolts(10.9 grade) torque specs are 48ft/lbs. ARP mains 65ft/lbs, but this can bend the main caps and press the clearance to zero.

So I suppose 12.9 grade bolts should be something between these? What would be the ideal sweetspot?

If you can read German THIS might be interesting for you. It has torque specs for different friction coefficients - READ different alloys and coatings; dry, oiled or with moly paste.

[pasbogdan]

No, not yet. This is an other engine I can throw in and drive the winter. Have to take apart the "main" engine an try to figure out why it's eating oil.

If all the rest is ok(valve seals,turbo,rings in piston grooves tolerances etc),honing grit to deep keeping and burning lot of oil,or grit to fine not keeping oil and destroying rings?