Example of some fine Cummins work quality

Not sure how you re torque 90 degrees

 

I have seen on a cummins sites ,somewhere, the final torque that equals the 300 + 90°
I understand how the retorque could help, only if you have a number to torque to.

 

Not the way @pushbroom described the procedure. That 90 degrees will probably gain you another 150 ft-lbs on top of the original 300. I wouldn't risk running an engine with insufficient headbolt torque. That's got blown headgasket written all over it.

 

Find the service manual online. Go off of that so you don't "have" to run an engine with insufficient torque. I am telling you how I did my engine based off of the service manual I found online.

 

Please explain to this mechanic how you retorque a bolt whose final torque value is not actually a real number? A torque value that is simply 90 degrees past 300 ft-lbs? It makes absolutely zero sense. What value do you set the torque wrench to?

 

300 ft lbs. then turn a quarter turn (aka 90*). There is no explanation for this. But since its in the manual, that's how to properly do it.

 

Yes we've established that is the torque procedure. I'm not questioning that. You keep talking about a re-torque though. A re-torque is when you go back after X amount of running hours and re-torque the bolts. Similar to how you're supposed to re-torque your wheel lugs 100-150km after you've had the wheels off. Just saying its not possible to re-torque the head bolts later because there is no specific number given for a final torque value, only 90 degrees past 300 ft-lbs. See what I'm saying?

 

I think you may be confusing us by refering to the final torque (the +90 degrees) as a re-torque.

 

The whole 90 degree thing doesn't always work out to exactly 90 degrees. And the final torque number will be different on each bolt.

You could end up at 89 degrees or 91 degrees give or take higher or lower.

 

Well that is a good question there. Here is what I did. I torqued each bolt in sequence the recommended increasing amounts. Ran 3 heat cycles, then took the covers off and, here it goes, LEFT THE TORQUE WRENCH ON 300 ft lbs and just made sure they were more than 300 ft lbs. If one came loose, you TIGHTEN IT WITH THE 300 FT LBS WRENCH I WAS USING BEFORE AND TURNED ANOTHER 90* AFTER IT CLICKED AT 300 FT LBS. You are asking questions you should be asking to one of the cummins engineers that designed it. So sorry for confusing you