: N* Headbolt Torque



air1ren
06-27-05, 07:21 PM
Just would like to get confirmation that the torque procedure in my 97 STS shop manual has not been superceded. It calls for 22 ft/lbs and then 2 more sequences of 60 degrees of rotation of the bolts. Is that still what everyone is doing? Thanks!

haymaker
06-27-05, 09:49 PM
You may want to recheck your shop manual on the two 60 degree sequences. I think the original procedure for your 97 STS M11 bolts was 22 lb/ft + 60 degrees + 60 degrees + 60 degrees (180 degrees total after the initial 22 lb/ft). I think the torque/torque angle was changed to 30 lb/ft + 70 + 60 + 60 degrees (190 degrees total after the initial 30 lb/ft). I used this second or newer sequence for head bolt tensioning after time-serting my N* but if I ever have to replace the head gaskets again I think I will try what some of the other forum members have done. They used the procedure of 30 lb/ft + 90 degrees + 90 degrees. Although I have never tried this procedure it would appear to be much simpler and IMHO could eliminate the torque angle gauge from the head bolt tensioning procedure.

air1ren
06-27-05, 10:27 PM
Thanks for the input. I am a bit nervous about too much torque with the aluminum block. I priced a Timesert kit today and it was $500.00 (!!!). I noticed that the fellow everyone refers to as Bbob, (who is an obvious authority) stated that pulled threads is only an occasional problem. So, with this in mind, I am thinking that if I do the torque correctly and there is no damage during disassembly, I should not have a problem...

Ranger
06-27-05, 11:28 PM
Not necessarily true. As Bbob (GM powertrain engineer) as said before sometimes the threads will come out with the bolts. Other times they will give as you torque them down. It has been reported by others that they had the threads fail in 10-20K after instalation. I am by no means an expert on the subject but from what I have read I would not put it back together without Timeserting. I thought the going price for a kit was $300. Have you checked Ebay?

air1ren
06-28-05, 04:58 PM
The Timesert web site led me to a Wurth distributor in Orlando, so I went there. I will give e-bay a try. I would definitely like to do the timesert, I just don't want to spend a ridiculous amount of money on it. Getting back to the torque, it sounds like there might be some variation on the required torque before turning the 90's or 60's. Where would I find out the current Cadillac recommendation?

haymaker
06-28-05, 08:45 PM
30 lb/ft + 70 degrees + 60 degrees + 60 degrees is the latest torque/torque angle spec. I am aware of.

As to the question of the need for time-serts, in your N*. After being in service for 8 years and if overheating caused by a blown head gasket is the reason for the disassembly? You may find some damaged female head bolt block threads and thus the need for the time-serts. When I disassembled my N* I noticed female block threads on many of the head bolts from one thread all the way up to of threads and the total head bolt thread engagement in the female block threads is just a little over 1 inch. Good luck.

air1ren
06-30-05, 07:09 PM
I just recently bought this car and I found a code indicating that the air conditioner had shut off at one time due to the engine coolant temp reaching a preset limit. I am not sure if the bad headgasket is due to someone not maintaining the coolant properly or due to an overheat. Either way, it appears that it must have got hot at least once...

I am not having any luck finding the time-sert kit on e-bay... I have looked in tools and automotive parts...