Retorque head bolts?
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From: Southern Ohio
Retorque head bolts? Hey all,
Just forged the bottom end and did a h/c swap. Are you supposed to re-torque the heads like you had to on the old style small blocks and big blocks. I've tried to find out, but I can't find anybody that says they do it.
Thanks
Just forged the bottom end and did a h/c swap. Are you supposed to re-torque the heads like you had to on the old style small blocks and big blocks. I've tried to find out, but I can't find anybody that says they do it.
Thanks
This is from ls1howto.com
Now lay the new head in place, making sure to get the head correctly on the two dowels that are in the block (dowels are in the bottom bolt holes..furthest back and front most). Go ahead and start threading the M-8 bolts back in by hand. You can reuse the small M-8 bolts if you wish, but you need to apply some locktite to them (GM locktite PN 12345382). If you bought new M-8 bolts they come with locktite pre-applied. Remember where the 2 shorter M-11 bolts went in (top row, furthest back and furthest front) and hand thread those in...then put the 8 longer ones in once again by hand.
Now, grab a socket wrench and lightly turn the bolts until they stop. Now for the very precice part. You need to get your torque wrench out now and fit it with a 3" extension and a 15mm socket.
Using the sequence illustrated above, torque all 10 15mm bolts to 22lb-ft.
Ok, now for a GREAT tip from Scott99Z. Take a felt tip marker and draw a horizontal line on the head of each bolt. This is very important.
Now, using the sequence illustrated above, turn all 10 15mm bolts an additional 90 degrees using a large socket wrench and a lot of muscle. Try to get as close to 90 degreees as possible...you may have to do multiple turns of 30 degrees or 2 turns of 45 degrees. When done all the lines on the bolt heads should be totally vertical.
Next, again using the sequence above, turn bolts 1 through 8 another 90 degrees. This will take an immense amount of effort...if you have a buddy helping both of you should turn the wrench simultanoiusly. These 8 bolts will now all have horizontal lines on them
Using the sequence above, turn bolts 9 and 10 an additional 50 degrees. Again, this will take a lot of effort. 50 degrees should result in a diagonal line on the bolts
Finally, using the sequence above, torque bolts 11 through 15 to 22 lb-ft.
Now lay the new head in place, making sure to get the head correctly on the two dowels that are in the block (dowels are in the bottom bolt holes..furthest back and front most). Go ahead and start threading the M-8 bolts back in by hand. You can reuse the small M-8 bolts if you wish, but you need to apply some locktite to them (GM locktite PN 12345382). If you bought new M-8 bolts they come with locktite pre-applied. Remember where the 2 shorter M-11 bolts went in (top row, furthest back and furthest front) and hand thread those in...then put the 8 longer ones in once again by hand.
Now, grab a socket wrench and lightly turn the bolts until they stop. Now for the very precice part. You need to get your torque wrench out now and fit it with a 3" extension and a 15mm socket.
Using the sequence illustrated above, torque all 10 15mm bolts to 22lb-ft.
Ok, now for a GREAT tip from Scott99Z. Take a felt tip marker and draw a horizontal line on the head of each bolt. This is very important.
Now, using the sequence illustrated above, turn all 10 15mm bolts an additional 90 degrees using a large socket wrench and a lot of muscle. Try to get as close to 90 degreees as possible...you may have to do multiple turns of 30 degrees or 2 turns of 45 degrees. When done all the lines on the bolt heads should be totally vertical.
Next, again using the sequence above, turn bolts 1 through 8 another 90 degrees. This will take an immense amount of effort...if you have a buddy helping both of you should turn the wrench simultanoiusly. These 8 bolts will now all have horizontal lines on them
Using the sequence above, turn bolts 9 and 10 an additional 50 degrees. Again, this will take a lot of effort. 50 degrees should result in a diagonal line on the bolts
Finally, using the sequence above, torque bolts 11 through 15 to 22 lb-ft.
