ovrrdrive

If you have to replace a few then I'd replace them all. If they were still in good condition and none had broken then I would reuse them on the 22RE. I reused mine and thus far have been fine.

Targetnut

That would be a good reason to throw them away. If in fact the bolts have stretched then they will certainly not hold the same clamping force.

when you put one of these engines together they are not really that critical like some of the more "special" makes, especially those from Europe. Because of the tolerance built into Toyotas from the manufacturer you have a greater margin for error. But this is no reason to tempt fate. Like I said before, if you don't find a reason to replace them, reuse them. Hoever,if there is any doubt or even just personal uncertainty how can you justify not replacing them?

thook

"How can you tell TTY head bolts from ordinary head bolts? TTY head bolts are typically longer and narrower than standard head bolts. Factory service manuals will tell you which applications use TTY bolts, and you can often tell from the head bolt tightening procedure if the bolts are TTY or standard. TTY bolts typically have an angle tightening specification rather than a specific torque value (which requires using an angle gauge when tightening the bolts).

The torque procedure for tightening a TTY head bolt involves tightening it until a certain torque reading is reached. Then the bolt is given an additional turn to a specified angle (say an additional 45 to 90 degrees) to load the bolt beyond its yield point for maximum clamping pressure."

Found this here:http://www.aa1car.com/library/2005/eb70536.htm

So, if the technical definition of a TTY HB is as stated here, and you're saying the 3vze HB's are not TTY, yet the FSM and even the TSB state a "TTY procedure" AND the HB's are "reusable", I can only figure that Toyota uses a TTY procedure for a non TTY bolt.???? This is making less and less sense to me.

Targetnut

As far as I know all TTY bolts are angle torqued, but there are alot of non-TTY bolts that are also angle torqued.

Angle torqueing is just a more accurate method of assuring a uniform stretch on the bolts because it reduces the effect of friction while torquing.

So just because it is angle torqued does not mean it is TTY.

The TTY bolts I have dealt with typically have a slightly reduced diameter in the shank area

thook

Thanks for the reply, Targetnut.

And, apologies for kind of hijacking the thread, mtrdrms.

I got the definitive answer I was looking for today. I've mentioned a friend of mine, Don Clark, a million times in other threads. He's been building and racing engines, a certified technician, machining instructor, blah, blah for eons. His answer about this question coincides with what I've read (outlined even in the link I provided) on the "clinical" definition of a TTY headbolt.

The 3vze HB's are, by definition, a TTY HB. The very fact that the procedure itself calls for setting to a specified torque followed by an additional angular torque classifies it as a TTY bolt. That's aside from the fact they are "slightly more slender" than conventional comparitively.

However, the argument has been (as Don Clark wells knows from his career involvement with automotive) for as long as TTY HB's have been used in manufacturing whether or not they can or should be reused. In many cases they can, but in some cases not. Depends on a number of variables and using plain common sense...and then he began spouting off a lot of technical info that went over my head....including the materials they're made with, bolt dimensions, procedure, torque values, (he used some word describing the characteristic of the threads including their pitch??), and on.

In his experience, he has reused TTY HB's many, many times (just like dealerships...including Toyota) without failure. I'd told him about Ted of engnbldr's experience with the bolt heads popping off after reusing 3vze HB's (and now that I remember, Ted has even told me in the past they were TTY) and he simply replied,"Well, that does happen". But, he added that...in his experience....that he has seen more cases of "reusable"/non-TTY bolt heads pop off than the other.

He also added that in the automotive world there is just as much opinion as there is fact about what is proper and what is not. And, even in the most "secure" set of circumstances there is failure that you can't guard against and you just have to be prepared for that.....all in regards to following accepted standards and procedure. There was a lot more to our long discussion that would clarify this "argument" in more detail, but I'm not up to writing that much...

Please understand, I wouldn't bother to go to this much trouble just to create a debate over something like this that is, to me, relatively insignificant, but I have both a 22re and a 3vze. It bothers me a tad to think I may have done something wrong....only because these types of grey areas....for me.. are time consuming and costly and I'm overly burned out on major repairs lately. With this issue, I believe it boils down to using common sense born out of sufficient knowledge and being willing to deal with uncontrollable variables that may cause whatever type of failure. Even brand new [fill in the blank] can fail.

In short...and more to the topic...even the TSB provided states that it is not necessary to replace an entire set of HB's if one or more fail inspection, in regards to the 3vze HB's. And, if you were to use this (Toyota Corp.'s recommendation) as any sort of gauge applied to the 22re HB's....which are, in fact, also reusable...then, to the OP, it is not necessary to replace the whole set.

Call a dealership repair shop and see if they have some good ones laying around. I've found they sometimes have used, but safely reusable parts. If they have parts, it's usually because they intend to use them in some repair application....which means they've also inspected them. Usually....

Hell, they may even sell singles brand new....I don't know.

Matt16

I didn't use antiseize compound on my head bolts originally. They've been fine so far, but I'd like to tighten them and use antiseize this time

Can I loosen them all a bit (1 turn) and then one by one, remove them, apply antiseize and re-torque to 58ft-lbs.?

thook

No, not after the engine has been run since the original installation. It would fine if you had just installed the gasket and went back to do it. But, then I'd torque them down tighter than 58.....63 or so.