mtrdrms

I broke one on my 22re and just extracted it and another one looks like it should be replaced but that leaves 8 bolts that are in pretty good condition. Do I really need to replace all of them? The manual calls for a good cleaning and reinstall. What do you guys think?

Thanks

Andy

Elton

to be on the safe side i would just replace them all if it was me

Matt16

The bolts stretch a bit once their tightened. They are really only good for one use.

thook

The 22r/re heabolts are completely reusable. It's only the HB's for the 3vze (and maybe other Toyota engines...don't know) that are not. They are "torque to yield"....meaning, they stretch.

The sad part is, new ones are only sold in sets. Maybe you could find a used one in good shape? I couldn't. They're were always in someone else's engine...lol.

isaac338

buy a new set and you'll have a bunch of spares for next time

Mr_Martinez1982

You didnt mention how/why it broke...

Its my understanding that ALL bolts stretch a bit, TTY bolts more than others for obvious reasons. Considering how much the bolts are and what you have to do to get to them, its cheaper in the long run to buy a new set. i would. i did.

dcg9381

This is somewhat of a "debated" topic.
I'm on the "replace them" side of the fence - they're a critical item, not that expensive (buy from engnbldr.com).

Chase the block with a tap before installing.
My recommendation, even on a stock motor is to use the ARPs - I have the feeling that the ARPs will help you get long life out of the somewhat problematic head gaskets.

drew303

I would replace them all. Ive never heard of HB's not stretching. I replace mine.

Targetnut

All bolts stretch when they are properly torqued, that what keeps them from coming loose.

Torque to yield bolts stretch beyond the yield point of the metal they are made of. this means that they will not return to their original length, and therefore should be replaced.

3VZ-E headbolts are not torque to yield. they are simply torqued using a different method which includes angle torquing to assure that the stretch is more uniform.

If the threads on your 22R headbolts are in good condition and you are sure they have not been over-tightened then it is OK to reuse them

As dcg9381 mentioned you should clean the holes in the block, but I would recommend using a thread chaser as opposed to a tap, because a tap will remove some metal.

Oh and make sure you oil the threads before installing them as this will help in getting a more uniform stretch.

javadoody

why wouldn't you replace them? for a couple of bucks you COULD save a hell of a lot of grief. don't go through a bunch of work on a motor and cut those kind of corners.

thook

Hmmm... All the research I'd ever done on forums and talking to the dealership and mechanics, the 3vze headbolts were always said to be TTY. Now, where do you get the idea they are not? I do know, however, that despite them being "called" TTY dealerships were reusing them.?????

Nevertheless, how is reusing a headbolt that is able to be reused cutting a corner? Yeah, metal stretches. The block stretches, the head stretches, exhaust stretches... blah, blah. People have reused 22r/re head bolts as long as they passed inspections. So, what's the problem? I know a number of people who have without issue.

Georgiadave

The bolts are not torque to yield, but why monkey with a bolt set that has already had a failure? I recommend anti sieze on the threads. Also, I would re torque after 24 hours to address gasket compression.

thook

Okay, what's this about? I've asked someone else about retorquing before and that someone said it wasn't necessary and even not good.

Pistonman

I just built a 22RE for my Bro. I always use new head bolts, after break in they all took some to get back to 58 ftlb.

Georgiadave

On torqueing the head bolts: They are torqued in steps, per the manual. When you retorque in 24 hours, the torque is the same as the final torque. If you have gasket compression, very likely in my experience, the retorque will bring things back to spec.

jct61765

Cheap insurance!

SEAIRESCUE

Since we seem to not know anything about the Toyota head bolts, may I suggest a mechanical college student get a few new ones from the dealer and pull then on an Instron and post the results? For the 3VZ, a similar exercise on a few used ones would help unravel the mystery of torque to yield.

http://www.portlandbolt.com/

These folks have a lot to offer, technically, regarding fasteners.

Until I touched a Toyota engine, I always reused my head bolts. Granted my "Cheby" head bolts were of constant cross-section and noting like the Toy bolts. Its my belief that the narrow shank bolts will produce false torques due to the fact that the narrow area will act like a spring.

Pragmatically, you do not want to torque to yield. Makes no dam sense. Bolt optimization implies a torque around 95% of yield. Enter the yield or plastic range and you change its properties which occludes the engineering.

Hope some college student will pull some bolts and tell us what they found.

My $0.02

Georgiadave

I agree it would be an interesting project to test some bolts to failure. The values would be of interest. Having said that, you can be sure the designers did just that and sized the bolts accordingly. Failures are usually in the shank of the bolt, not in the threads, which indicates the shank in twisting from over torque or is frozen in the threaded portion of the block. We can back into the strength of the bolts by calculating the force required to break the bolt. A formula for working strength of 1/2 inch bolts from Machinery's Handbook is:

Permissible load = Stress in tension X (root diameter of bolt thread - .25 nominal outside diameter of bolt)

W = 10,000 PSI(.126 - (.25 X.375) or 10,000 X .03225) = 322 pounds

I assumed a working load of 10,000 PSI cylinder pressure and a 1/2 inch bolt thread size with a slightly smaller shank diameter than the threads. If my analysis is correct, it takes a force of about 325 pounds to break a 1/2 inch bolt of the Toyota headbolt configuration.

I have no idea what the max cylinder pressure is, I guessed, and I used SAE dimensions because that is what I had handy. I think the head bolt thread size is about 12-13 MM, which is 1/2 inch.

All of this is just to illustrate the point. Empiricaly, I must say that over 300 foot pounds of torque to break a heat treated bolt of this size sounds about right to me.

Targetnut

I worked for a toyota dealership during the bulk of the headgasket recalls for the 3VZ-Es.
I've personally torqued several thousand 3VZ-E head bolts and only replaced a handfull because there was something obviously wrong with them.

Your internet forum research is flawed in the fact that you are getting info from people who know little about what they are talking about.

But don't take my word for it, here is a link to the Toyota TSB about the subject. add this to your research

TSB on headbolts for 3VZ-E

thook

Ooooo....somethings even the techies at the local dealer don't know. Hm...I'll have to send that link to my friend at the Toyota Parts Dept. Very interesting....thank you. Wish I'd known. That would explain some of the confusion (upon my inquiries) with some of the mechanics there.....the ones saying they'd reused them without issue.

Also, interesting because the folks at engnbldr have bad luck reusing them on many accounts. Like bolt heads just popping right off after installation. Maybe they didn't know about this TSB? Hm....

I have to add something here. I've been doing some reading since this thread. Even though a headbolt may be "reusable", and for all apparent reasons is in good shape, I'm finding a discrepancy with what I hear and read and what I'm experiencing. The headbolts on my 22re look fine. Clean threads and no pitting. However, according the a procedure given by engnbldr (thanks Mt. Goat...and Ted) a headbolt....new or used...should be able to be threaded easily in and out of the block by finger....provided the block holes and threads and bolts thread are lightly lubed and clean. Well, mine are. I can easily thread a chaser in and out with very little resistance from top to bottom and back again. BUT! A few of my "used" headbolts will not do so. All I can figure is the threads on those bolts have stretched. I'm strongly guessing this is going to give me an uneven clamping force on the head/block/gasket assembly. Targetnut...or anyone who'd know...what would you think?