I know the procedure is 15ft-lbs+90+90. BUT I still want to know what the actual torque value is. Does anyone know the actual value. I suspect it is between 70 and 90 ft-lbs. Can anyone tell me?

 

Wow. No takers?

 

There is no actual torque value to my knowledge. You have to do the 15lb then wait then 90 degrees them wait then 90 degrees. That allows the head bolt to slowly stretch so it doesn't break and surpasses difference in friction issues like temperature and whether there is oil anywhere that there would be friction against the bolt.

 

Alex is correct.

Take the time to search here or the web it educate yourself about searching and TTY head bolts.
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UPDATE:
Trust me, I have taken the time and I have read and followed the RAVE.
My issue here was that while teaching helping my son learn to work on the DiscoII, he and I and we were not sure if he performed the last 90 degree torque on the number 5 bolt in the LHS head sequence. That was a question. Instead of just doing another 90 degree or risking that the #5 would be missing the last 90 degree I wanted a way to help determine if the #5 was indeed torqued 90 twice. The obvious alternative of course would have been to remove all bolts, order a new gasket and new bolts, wait a week and try again. Instead I determined from the #9 bolt in the sequence (we knew it had been turned twice) that the torque value was 80 ft lbs. I then put the torque wrench on #5 and indeed the bolt held to 80 ft lbs before moving ever so slightly. Now I can sleep better.

Thank you all.

 

i did this exact thing on a 4.6 L mustang gt and it took untold amounts of nitrous no problem. I pulled an ARP head stud at 70ft lbs last weekend on my disco so 80 makes me nervous.

 

Thanks for your explanation. It might be helpful if somebody invested the time and money on several bolt sets, do some testing and then report back with the results on the torques at 90 and 180. One of the newer digital TWs that hold the torque in memory would be ideal to use.
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It's helpful to understand your context - that you were trying to diagnose whether or not the 15/90/90 sequence was completed and not trying to use a torque value instead. I'm glad that you confirmed all is well.

 

If you mark the bolts with a grease marker you can tell if the bolt has turned 180 degrees.

 

I will definitely do this in the future.