proper heat cycle/retorquing after replacing head gasket?

[jml74]

I found a few articles/posts on here and Randakk's site about doing a heat cycle and retorque after head gasket replacement, but nothing that I saw spells out what constitutes a heat cycle in this context. I didn't touch the pistons or cylinders, so should I just let it run until the thermostat opens? What about retorquing afterwards? Randakk recommends it, but I saw some posts on here pointing out that OEMs don't specify it. (Actually, given the relatively low amount of effort involved, the more I think about that step the more I think I'll do it unless somebody has a compelling reason not to.)

And in case anybody runs across this post in the future and has the same question I did: Randakk's retorquing procedure is to crack each bolt and retorque one at a time, in sequence. DO NOT loosen all the bolts at once. He clarified this in a comment on that post.

[OCR]

Yep, you want it warm enough for the thermostat to open an circulate warm coolant thoroughly.
After is cools down completely, retorque. Repeat as needed.

[salukispeed]

Just my opinion but run it long enough to make normal operating temp and allow the fan to cycle if it works properly and then wait over night for complete cool down then re-torque the bolts one at a time by loosening them maybe a 1/4 turn then torque to spec in the normal proper sequence. you do not want to loosen very much just enough to get a fresh feel of the tension

[Gowing]

When I did both headgaskets on my 75, mine held fine.over 10000 miles now. Used all Honda parts.
No copper spray, no re torque. Not necessary. IMHO after reading every post I could find on the subject.
Just torque your bolts in crisscross pattern and maybe 5 times to get to 45.
20,25,30,40, then to 45. Sneak up to 45.
Information given for amusement value only.

[Whiskerfish]

Have done more than a few head gaskets and never done a re-torque. Never had a failure.

[ericheath]

I’ll bet all the guys above will attest that they cleaned the bolt threads and block threads making sure grease wasn’t caked up in the bottom of the block holes and put grease under the washers and on the threads.

[salukispeed]

Sad to say not everyone is aware or does a good job of this cleaning and prep but it is probably more critical then a re-torque. OE does not re-torque

[Whiskerfish]

Yes i do chase the threads and lube the bolts and washers. Both those are critical to achieving the proper clamping pressure.

Also very often I will let it set overnight and redo the torques before closing things up just as a sanity check. Do not recall one ever "breaking torque" when doing that though.

[Oldewing]

firmly in line behind WF, clean bolts, chase threads, lube and torque..done and done.

[chewy999]

I’ll bet all the guys above will attest that they cleaned the bolt threads and block threads making sure grease wasn’t caked up in the bottom of the block holes and put grease under the washers and on the threads.

That's just good engineering practice.

[jml74]

I've been away for a bit and just caught up on the last few replies to this thread. My understanding has always been that torque specs only apply to clean, dry bolts, so if you're lubing the threads (or still have old grease on them) you're actually going to overtorque.

[hatchward]

Honda FSM

20181003_112602.jpg (96.05 KiB) Viewed 181 times

[jml74]

Interesting. Thanks for sharing.

[robin1731]

Yeah, some bolts require lube and others don't. That is why it's always a good idea to have a service manual.

.

[Sidecar Bob]

And to actually read it.