Rarity Honda Head Bolts Stretch?

[firefighterwhite89]

I've been explained, by someone who worked at a machine shop, with a book called "Head bolts & Studs torque specs master manual" or something to that tune, that in fact, our head bolts don't stretch. So, after replacing them, now i'm informed they don't stretch? Apparently stretch bolts is a ford and chevy thing mostly. Hmmm...Our cars were listed as ones that weren't use once. Hmmm...this hold true? I'd think 20+ years of extreme heat and force would aquire a replacing at some point, eh?

[Vanilla Sky]

While I'm not sure whether or not they're TTY or not, I do know they should be checked if they are to be reused. Personally, I'd just measure them. If I had one out of spec, I'd go ahead and replace them all. They're not all that expensive, and I feel they're a good insurance policy.

[forrest89sei]

Theres a Pretty Big Debate on both sides,
From what I have gathered it's safe to reuse head bolts if you make sure to clean them up, cleaning the threads, soaking them in oil and Cleaning the thread holes on the block are all good practices.

Others get brand new Bolts from Honda OR Get ARP Studs, I don't see a problem with that, you know that the OEM Honda Bolts have been on your motor for over 20 years so you know there a quality part, and We all know ARP makes Great Studs.

I think with either practice just make sure the threads on the block are nice a clean and you'll be fine

[dieselgus]

Generally it is good practise to put in new head bolts anyways. Think about the amount of stress they take over the course of their service life (same goes for lower control arm bolts). If you are going through the expense of having the head off the motor, what is a few dollars more, right?

Stretch (or torque to yield) bolts are actually very common on a lot of vehicles, especially newer ones. Usually the dead give away is a torque spec that reads say 186ft-lbs+45 degrees. You torque to 186 ft-lbs, then add an additional bolt rotation of 45 degrees. That is your stretch.....they are designed for it believe it or not. Also pretty common in aviation as well come to think of it. VW, MB, BMW use them all over the place in higher stress applications besides the heads such as motor mounts (many a TDI timing belt change has often overlooked the two TTY bolts on the passenger front mount I am sure), suspension, transmission, diffs, etc.

Still real wierd the first time you have to torque something using degrees I tell ya!

[Dr_Snooz]

Our head bolts are not TTY, which is to say they were not designed to stretch after one torquing and be replaced when loosened. That's not to say that they won't ever fatigue. I reused my head bolts when I did my rebuild but I wouldn't say you did wrong by buying new ones.

[firefighterwhite89]

Our head bolts are not TTY, which is to say they were not designed to stretch after one torquing and be replaced when loosened. That's not to say that they won't ever fatigue. I reused my head bolts when I did my rebuild but I wouldn't say you did wrong by buying new ones.

Hey guys, what's the Length of the bolt exactly? And, i'd imagine they have a zero tolerance to stretch/fatigue?

[2oodoor]

guess you could use a thread pitch guage and check em

[firefighterwhite89]

anyone know the thread pitch? M12x1.5?