: Latest head bolt tightening spec?



Loose screw
04-02-05, 07:50 PM
What's the latest tightening specs for the head bolts I did a search and found different numbers being used.

BeelzeBob
04-02-05, 08:01 PM
Tighten the bolts in sequence 30 nm + 60 degrees, then on a second pass give them an additional 60 degrees, then on a final pass an additional 60 degrees. That will work fine. There are several different tensioning specs but they basically do the same thing. With the new gaskets and new bolts and fresh timeserts the 30 nm + 60 + 60 + 60 will be fine.


You did tighten the damper bolt correctly, right...??? Seems like there has been a rash of people lately working on Norhtstar engines and not getting the damper bolt tight and loosing oil pressure and taking out the lower end.....

Loose screw
04-02-05, 10:12 PM
Thanks Bbob The timing chain, oil pump, front cover and damper are on the agenda for tomorrow.

A man can only screw up so many things in one day.

I had a terrible thing happen while tightenig down the head bolts with the spec you gave, on the last round of 60 degrees, on the last head, on the third to last head bolt I felt a sudden give, a quick tiwst at 50 degress - I thought for sure I had pulled a Timesert out. Of course I tried to expressed myself appropriately for the occation. *Z/?$#X@?!

After a couple of minutes I decided I would tighten the two remain bolts and see if they would hold. As I tried the next bolt the short 3/8 adapter I was using twisted into two pieces without turning the bolt. I found an impact adapter and finished the 10 degrees on the on bolt and then did the other two. And to test that they were all tight I adjust a torque wrench to where it was just below what would turn a bolt that I sure was ok and then cheched all the others and they where would not turn.

Is it advisable to undo the bolts on that head and repeat the tightening process reusing the head gasket and bolts if the engine has not run?

BeelzeBob
04-02-05, 10:28 PM
Thanks Bbob The timing chain, oil pump, front cover and damper are on the agenda for tomorrow.

A man can only screw up so many things in one day.

I had a terrible thing happen while tightenig down the head bolts with the spec you gave, on the last round of 60 degrees, on the last head, on the third to last head bolt I felt a sudden give, a quick tiwst at 50 degress - I thought for sure I had pulled a Timesert out. Of course I tried to expressed myself appropriately for the occation. *Z/?$#X@?!

After a couple of minutes I decided I would tighten the two remain bolts and see if they would hold. As I tried the next bolt the short 3/8 adapter I was using twisted into two pieces without turning the bolt. I found an impact adapter and finished the 10 degrees on the on bolt and then did the other two. And to test that they were all tight I adjust a torque wrench to where it was just below what would turn a bolt that I sure was ok and then cheched all the others and they where would not turn.

Is it advisable to undo the bolts on that head and repeat the tightening process reusing the head gasket and bolts if the engine has not run?

You should be fine. Glad it was an adapter....LOL LOL I wouldn't touch the head bolts at all. If you got close on the angle after the adapter twisted off then you will be OK.

Loose screw
04-03-05, 12:18 AM
Thanks Bbob
This engine is a 94 and has 142,000 mile on it is the harmonic damper likely to fail soon? It would be lot easier to repalce it now if it will go soon any way. Any way to tell?

That 2005 Bonneville GXP must be a great car if you driving it instead of a Cadillac?