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If it's not really about tuning or wiring. Then it belongs in here.
When using anti-seize how much do you reduce torque by from spec?
I keep rounding the heads of timing tensioner bolts and buying new ones. I’ve avoided using anti-seize on it because it’s for the timing tensioner and you don’t want that one to loosen up. But I always have problems with this one. I just blew up 3 sockets trying to get it off. Had to run out and buy the hardened sockets to get it off. I think there may be greater risk in not using the anti-seize.
I definitely don’t want to overtighten it either a as result of using anti-seize so thus the question.
I assume this is for your Honda B series engine?
I'm not familiar with the specific engine, the fasteners, or the tools you're using, so some general questions/observations.
What is the specified assembly method Honda give - some manufacturers specify dry unless otherwise stated, some say lightly oiled unless..., some will specify anti-seize or thread-lock unless otherwise stated...
Which brings us to what the affect of change in lubricant, if even used, will have on the torque-stretch relationship. Rather foolishly, as it turns out, I thought this would be a simple co-efficent of friction relationship, but it seems not. It seems, in practice to be anything from 10 to 50% less torque is required, even more in some instances, depending on the original and actually used lubricants, the materials used, and their condition/surface finish. I would appreciate other's input on this. However, you 'might' find this of interest - https://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html and this is also a good over-view - http://www.smartbolts.com/insights/impact-lubricants-torque-readings/ There are some other potentially interesting tests, but they're PTV, so I didn't follow up on them.
If you are currently using a locking compound on the fastener, with very few exceptions, they break down with heat (150-180C is common) and turn liquid, so if you can heat it it will loosen more easily. As they cool, they usually set again, so don't take your time.
I don't know what you mean about "blowing up" three sockets, the only thing that comes to mind is the use of really cheap, rubbish, sockets rather than using a reputable brand with a close fitting, correctly sized, socket - if the head is an external hex', use a single hex' socket - it will load the head more effectively. If double hex', ditto. If it's an internal hex, poly-spline, or torx head, use the correct socket for that specific design. IMO, tools are one of those things you DO NOT buy cheap - you just need one stripped or rounded head caused by a poor tool to potentiall cover the cost of premium tools several times over.
What bolts are you using for the tensioner - are they genuine Honda parts or something you've been buying at the local hardware store? Honda parts are normally darned good, but if you don't know what you're buying at the hardware store you could be running into problems there as fastener quality varies a LOT depending on specification. An 8.8 is the minimum I would consider, 10.9 probably my choice, and 12.9 would be overkill. Just make sure it's the same length as the OEM bolts, so you don't risk pulling a thread.
If I were seriously concerned, I'd pick up a cleaning tap (they are NOT the same as end/plug/finishing taps - they are designed to NOT remove material) and an extra long bolt for checking thread engagement. Gently clean out the threads in the holes, then lightly screw in the longth bolt, mark it, and that will tell you the maximum possible thread engagement, add the thickness of the tension plate, etc, and that'll tell you the potential maximum bolt length, allowing for a couple of threads at the end.
Thank you for the comprehensive answer. Very helpful. I have never used anti-seize on any bolts that go into the engine before unless the service manual specifically says to but I was considering using it for the tensioner bolt until I read your post. I think better sockets are the solution. I do always use anti-sieze on suspension bolts and that works for me since those bolts are always the worst later on.
I did run out and buy some nice flank drive impact sockets and that was able to get it off (with a wrench not with an impact gun). What a difference better sockets make.
I also ordered the thread chaser as per your suggestion.
Lastly I only use oem nuts and bolts, or ARP.