Retorque heads

[BigBlueIron]

This is relation to an old engine not a fresh rebuild. I have, be it a waste of time or maybe even the wrong thing to do re-torqued heads on old engines. Method I use, take bolt out clean threads blow out with air and maybe even run a tap down the hole if nasty, light coat of oil on threads and pull to spec in one swing. Do this on each bolt in order. Intake removed.

I had to pull a head bolt for some reason I cant remember and reinstall, when I did I noted the position of the head and it ended up about 15* or so past where it was (tighter). So I did them all, this was on a junkyard 390 that has been nothing but abused since. I also did this recently on a Cleveland  and got maybe 5* this engine had a "recent" rebuild.

Anyone else ever do this? Should I quit doing it? I can't see what it would hurt, obviously the gaskets have relaxed a little over the years and I feel this is bringing the clamp load back where it should be.

Just wondering what peoples thoughts where on the matter.

[C6AE]

By using a three step torque method you can insure the bolt threads and the block threads "fit" each other.

[427mach1]

I personally would not run a tap down each hole without being able to flush and blow them out completely.  The threads are 3 - 4 inches down the clearance hole so it would be difficult to ensure that all the dirt was removed without removing the head.   I would not want to risk any chips or dirt being left behind or finding their way into other parts of the engine.  If I were to re-torque, I would simply set the torque wrench to the final torque setting and re-torque them in the proper sequence without removing any bolts.

[Falcon67]

I don't go back and re-torque head bolts, never saw the need if done correctly in the first place.  As noted, if I did it would be to set the wrench at the final setting and test.  Would not remove anything - why, that's just make-work.  Also, just for full disclosure, I never use head bolts anymore.  I prefer studs.  On anything I can get, everywhere I can fit.  Even the cheap, tiny. chinese 72cc engine I'm working on uses studs to retain the head. 

Also - you clean the threads before final assembly and you would use a clean out tap, not a regular tap that is meant to cut threads.  Using a full thread tap can weaken the existing threads by removing material. 

[blykins]

On brand new engines, I always retorque head bolts/studs.   First pass, I do in 3 steps to full torque.  Second pass, I loosen one fastener at a time, then pull full torque in one swing.