If they are used no need as they have crushed,....if new I would let them sit overnight then retorque
Total waste of time if you do such! Any factory assembled motor that used steel shin gaskets never retorqued them, the cars where satsrted , driven off the assembly line and that was it.
I check the bolts after cool down. I recheck head and intake bolts on all engines that I build. I have used steel shim, FelPro blues, factory composite, Cometic, TA etc. I check the torque on all engines no matter what gaskets are used. Periodically I will find bolts that have changed. The steel shim gaskets have less tendency to change as opposed to the composite gaskets. The center bolt under the valve cover and the end head bolts are the usual culprits that I find. Sometimes it takes 3 or more warmup and cool down cycles for the bolt tq to stay put. Rechecking head bolt tq is very critical with aluminum heads. A few years ago I had an issue with blown head gaskets with aluminum heads. I read through the TA catalog and discovered the retorquing process recommendation. Haven't had an issue since. I consider it cheap insurance as opposed to replacing head gaskets after the engine is in the car.
Slightly off topic but I was amazed how many times I had to retorque the TA orange crush gaskets before they settled down.
Next question....I believe the correct way is to back off each bolt one at a time and bring back up to spec rather that just seeing if they take any. Opinions?
Re-torque or not is entirely gasket dependent. Bolts lose torque because the distance between the clamping surfaces changes. On some, the gasket is coated with a cold sealer, such as the TA "orange crush" gasket. The cold sealer oozing off the gasket from compression, changing the clamping distance, is what causes the bolts to loose torque. You have to chase that gasket down, over a period of a couple days.. Most all the engines I build use the Fel Pro Blue gaskets. In 25 years of serious engine building, I have never had one fail. We used them on our 13-1 compression race engines back in the day, they sealed so much better than the stamped steels, and we never had a failure. They will go on the motors I am prepping right now, for my return to drag racing. Forced induction stuff gets the MLS gaskets, and serious high compression stuff get's o-rings in the block, and dead soft copper gaskets. Had one motor with a temp sensitive leak, you could see trails where it leaked for a little bit during the heat cycle...it was a Stage 2, and I attributed that to not having the extra bolts on the exhaust side of the head. Later it was learned that the installing shop could not wire the MSD distributor correctly, and as such that engine was subjected to extreme head temperatures, due a weak spark causing raw fuel to be burned in the exhaust port/headers. Weak spark acts exactly like retarded timing in this regard, and all of you have seen the headers glow on these dyno videos, where they don't have the timing set correctly. Those gaskets did not fail, they just intermittently leaked, but no gasket would have survived that torture chamber. I would not be surprised if the combustion temps were north of 1500 degrees under light throttle. Got hot enough to close the top ring lands up on the forged pistons.. after all was said and done, I was impressed that the good old blues held up to that. I have had 3 head gaskets on my motors fail that I know of. 1 was a HP Fel Pro, and two were the TA gasket. The TA head gasket failures were from severe detonation, caused by an MSD box going berserk whenever it felt like it.. that failure was a mystery, it took out the LH head gasket on a 600 HP motor that had been together for a decade, out the blue... I replaced it, and not much running time later, it took the RH gasket out, and broke a chunk out of the top of the forged piston... We chalked it up to a bad tank of gas.. The current owner of that car wanted to tame it down a bit, he was just doing car shows and street driving it.. so I put in a milder 455 for him.. Driving it over to his house, I experienced the ignition failure. It was wild.. car would buck for a second and then shut down.. Cycle the key and it would start right up. By chance, it happened right when I pulled it into his driveway.. it killed, and I could hear a strange buzzing noise under the hood.. it was from the spark just continuously jumping from the rotor to whatever cylinder was lined up on the cap.. unplugged the MSD box and it stopped.. Ya, that will play havoc with your spark timing! So really, I have had one gasket that I am aware of, in 130 plus BBB engines fail.. I suspect that one was from a torque issue. It leaked water on the end of the cylinder head with the water passage in the block.. That was the HP Fel Pro gasket on a bracket motor, at just 10.5-1 compression.. that one remains a bit of a mystery.. could simply have been product failure. Now, let's talk about the real problem with head gaskets and torquing procedures. First off, you have to have clean bolts, and clean threads.. bead blasting stock bolts really helps them.. not so much with new ARP bolts. I have not seen the need to cycle the torque on new head bolts, like we do with rod bolts. The main thing your doing wrong is... The lube your using.... If your not using CMD-3 for bolt lube, your shortchanging your engine. Use it once, and you will understand. Correct torque is achieved when the bolt is stretched properly, and to do this, it must move smoothly against the contact surfaces.. those being the threads, and the cylinder head under the bolt heat. Ever had the torque wrench "give" when your torquing? I bet you have...Skips a bit and makes a noise... almost always on the final torque step.. this is the contact area between the head/bolt letting go.. it was bound due to a lack of lubrication. That totally screws up both the stretch of that bolt, and your attempt to clamp the head down evenly. CMD 3, is the only lube that I have ever used in which you will not experience this. And that includes the new ARP Ultra Torque lube.. The simple fact is that if you want smooth accurate torque values on your fasteners, you use CMD 3.. or you end up with something else. With CMD 3, I never re-torque.. I don't use the cold sealer gaskets, I use the Fel Pro Blues, dead soft copper or MLS gaskets, and they don't require it. The bolts are stretched properly once, the gaskets don't crush with a heat cycle, so there is no need. My clamping distance is not changing. I used to re-torque everything.. but after a careful study of one of my engines, and careful marking of the bolt location, proper re-lubing of the fastener, and then re-torquing, the bolts all came back to exactly the same position. No bolt was noted as loose when I un-torqued in the process. This was a motor that had half a dozen heat cycles on it, with TA alum Stage 1 heads. I actually was worried about the brand new head castings not coming back to size after several heat cycles, but that did not seem to be an issue. As time goes on, I occasional repeat the test, and have never had different results. So- re-torque if you must, due to gaskets your using, or to make yourself feel better, but I will tell you that if you use the correct lube and procedures, your going to have a lot less problems. The only negative with CMD 3 is that it melts at normal engine temps, so if your having to retorque after a heat cycle, then you must re-lube the bolt.. just like if your using oil on your bolts.. But with the correct procedures on the cold sealer gaskets during assembly, I can't see the need to ever retorque after a heat cycle. Get this lube.. https://www.amazon.com/Dart-CMD-Extreme-Pressure-Lube/dp/B07B8VM46J/ref=sr_1_4?gclid=CjwKCAjw7cGUBhA9EiwArBAvok5n7A200a6WnDmDNwW42R_tqOOthxPpR4OJKtCItLel2nZLBL8lXBoCh0sQAvD_BwE&hvadid=552554064637&hvdev=c&hvlocphy=9019487&hvnetw=g&hvqmt=b&hvrand=9705395717837023452&hvtargid=kwd-1258434188331&hydadcr=12970_9726901&keywords=cmd+pressure+lube+3&qid=1653660150&sr=8-4&th=1 I use this on all critical torque surfaces, where we don't use thread locker.. Mains, rods, head, intake bolts.. this the lube specified by many HP head Vendors, as well as you get a small tube of this with every set of Molnar rods. This lube is used in both the critical setup process pre-machining, as well as for setup/checking, and final assembly, to insure accurate torque, which is a key component to having the cast iron pull the same every time. This is an absolute must to maintain round bores. and consistent clearances. JW
I used to use white lead as a dead center, center point lube while o.d. grinding 1" to 4" dia spindle shaft bearing journals, that were undercut, then hard chromed to return diameters to spec. until I found the CMD #3. Heavy duty lube is an understatement.
True. Not convenient, but true. Thanks for that. Comforting to know that common gaskets are also good gaskets. Some time ago--maybe a dozen years back--ARP changed the "formula" for their thread lube. Their advertising admitted that it wasn't as "slippery" as the "old" formula, but that wasn't important. What was important was the consistency of results the "new" stuff provided. Seems to me that they adjusted all their recommended torque values "up" a little bit to compensate for the new lube's reduced lubrication. I'm a little concerned that if a person uses extra-slippery lube on those fasteners, you'd over-stretch them. OTOH, you're having excellent results as-is. https://arp-bolts.com/p/technical.php
