: Blocks cracking on final head torque?



banditzed
09-29-07, 02:12 AM
Talked to the foreman at the machine shop today about his experience rebuilding Northstars. Says he has had blocks crack in the "lifter valley" when
doing the last pass on the head bolt torque. This is on blocks that have been freshly timeserted. Now his solution is to only go 45 degrees on the last pass of the bolts rather than 60 degrees. Any thoughts?

97Concours1
10-01-07, 04:47 AM
That last 60 degree pass is scary. I kind of wanted to stop at about 45 degrees too. How many Northstars has he done, stopping at 45 degrees? How many miles do they have on them (after the repair?) If he is having good success, I think I'll stop at 45 degrees on the next one I do.

AJxtcman
10-01-07, 01:16 PM
Talked to the foreman at the machine shop today about his experience rebuilding Northstars. Says he has had blocks crack in the "lifter valley" when
doing the last pass on the head bolt torque. This is on blocks that have been freshly timeserted. Now his solution is to only go 45 degrees on the last pass of the bolts rather than 60 degrees. Any thoughts?

No lifter valley
??

dkozloski
10-01-07, 02:50 PM
No lifter valley
??
Sounds like somebody down at Cooter's Garage is halucinating again. No lifter valley in a Northstar. It's DOHC.

clarkz71
10-01-07, 03:53 PM
I think he just means the area under the intake manifold, that's why
he has it in quotes.

banditzed
10-02-07, 01:24 AM
I used the term "lifter gallery" loosely. The shop foreman says they have cracked in the bosses below the intake. I think he's only done a couple with his revised torque, maybe 10K miles but no problems so far. I should add that these were done for a local dealer who won't touch them in his shop.

AJxtcman
10-02-07, 07:04 PM
It really doesn't matter any way. The Old POS blocks can't hold 30 lb ft when bad!!

The factory specs are
Torque Specifications:


1993-1999 Head Bolt Torque


• First Pass 40Nm(30 lb ft)


• Second Pass -- 70 Degrees


• Third Pass -- 60 Degrees


• Fourth Pass -- 60 Degrees (190 Degrees total)




2000-2003 Head Bolt Torque:


• First Pass 40Nm(30 lb ft)


• Second Pass -- 70 Degrees


• Third Pass -- 60 Degrees


• Fourth Pass -- 45 Degrees (175 Degrees total)

99_WHITE_STS
10-17-07, 12:29 AM
I am just getting ready to "button" my 99' up, after installing Norms inserts, and am getting nervous about the 4th pass @ 60 dergrees. What do you think about playing it safe and just doing the 45 degrees ? AJ ??

Thanks, Jim

tateos
10-30-07, 09:49 PM
How do you like Norms's inserts - so far? I plan to start the extrication process on my '97 ETC this weekend.

Richard Moore
Fountain Hills, AZ