HELP! Exhaust studs stretching!!

[jesper moreau]

>The list is pretty quiet today, hope someone can help... So I guess even 
>the new
>style studs are stretching on me and I didn't realize. It doesn't make 
>sense
>though. The Bentley says 26 ft-lbs for the MC motor which uses the same 
>studs
>and nuts. I checked the Haynes manual and they say 22 ft-lbs. The 
>turbo-diesel
>in the Bentley says 18 ft-lbs. 15-16 ft-lbs is s'posed to be the standard 
>torque
>on class 8.8 M8 hardware, but there aren't any grade/class markings on the 
>stud
>or nut, so I'm lost. What is the proper torque? How do you guys normally do
>this??? BTDT's? Thanks.

>Also, I figured out why the studs were bending a little... i guess the
>spiral-locks weren't tapped in totally perpendicular to the gasket surface, 
>so
>when the nut is tightened, the nut bends the stud as the nut is pulled up
>against the perpendicular manifold surface. Ah well, I guess I can live w/ 
>that
>for now.

>-Ameer


I was just reading my Bently and it says 22 Ft/lbs or 30 NM. I just did my 
head and had 3 studs break during removal of the studs. Had to helicoil 2 of 
them. They snugged right up. I do suggest that u use new studs. They become 
very brittle after use. (Hence the turning and stretching you're 
experiencing) I am assuming your head is still on the block. If you have to 
do a helicoil or even replace one, I really suggest that you remove the head 
if you want to do it right. There is nothing like a straight tap and dye. I 
went to a machine shop and drilled the holes on a professional air assisted 
drill press table. It made  all the difference in the world. Did my coils 
turn.... heck no. so the moral of the story:
Yes it will cost u extra to remove the head
but it could cost you a lot more to develope a manifold leak and create heat 
damage to your top end.
Plus im mean come on.... the piece of mind that you did it right - 
priceless!
Good luck!
Zep


"Shared joy is double joy and shared sorrow is half sorrow"...



"Shared joy is double joy and shared sorrow is half sorrow"

_________________________________________________________________
MSN Life Events gives you the tips and tools to handle the turning points in 
your life. http://lifeevents.msn.com