All of my brand new bolts stretched

My guess is your torque wrench is not calibrated anymore. Do you reset it to zero before storing it?

Not sure I would worry about on the cam assembly. However the head bolts are another story.

 

Are you certain you have FT lbs? And the correct torque?
Perhaps it's INCH lbs and not FT lbs?
I honestly don't remember which it is. I know they are not very tight.
Also, make sure you are NOT reading "NM".
Because 1.1 NM, is 10ftbs. So 20NM, would be about 220 ftlb's.




I don't believe the cam bolts are stretch bolts. The head bolts are.

Tighten them down by hand, or hand held socket. Follow the sequence pattern.
You can push down on the section of the cam that the spring is holding up.
After they are hand tight, the cam caps should be flat against the head. I would say maybe
1/2 turn is all the bolt would move with the correct torque.

 

The spec is Torque: 27 N·m (275 kgf·cm, 20ft·lbf)

1 NM is 0.7376 ftlbs
20 NM IS 14.75 ftlbs which is reduced torque.

Use of oil on the threads can cause stretching even though the torque wrench indicates 20 ftlbs. Most Toyota torque specs are for clean and dry threads except for the head bolts where a specific lubricant is recommended.

 

See Post #4....

 

1.1 NM = about 10 INCH-pounds.

 

Yep, brain fart! My mistake. Thanks for catching that.....

 

What about the head bolts you tightened too much? Those being stretched is more concerning than the cam bolts. Also please don't start a new thread for the same job. Stick with the old thread so people helping you have all of the information in one location.

 

The biggest torque problem is when the fastener is specified for in lbs and someone torques that number with a ft lbs torque wrench. That mistake would end up 12 times over torqued.

Which is not a concern when the cam housing bolts are spec'd at 20 ft lbs.

RTV is not oil. Torque values are specified as dry or lubricated. When dry is specified, an oil like SAE 30 can make a bolt get tighter with less torque.


If you lubricated with 30 weight oil you would have to reduce the torque by 35-45% to end up with proper tension or clamping force.

Head and main bearing bolts are a few exceptions but even then a specified assembly lube is needed.

Usually it does not matter one way or the other unless you end up breaking a bolt.

Your head bolts are ok. If you read the attachment in post 5 it suggests replacing the sealant after loosening cam housing bolts.

 

Check to make sure there is not fluid in the holes the bolts go into.
If oil got in there, you can't compress it.
You can wrap a rag around the hole and use the red tube on the nozzle and put it at the bottom
of the hole and spray, carb or brake cleaner. The rag will keep it from getting all over the place.

If you have a compressor, you can spray air in it. Then use the brake/carb clean and air.
Make sure it's dry.

Where did you get 20ftlb from? Are you certain that is correct?

 

Ok. Not sure why.

No. Now you would be guessing. Clean and dry at 20 ft lbs. Clean like dogman suggests.

The repair manual says 20 ft lbs as listed in the attachment in post 5.

 

That's happened more than once with these:



They're trivial locator bolts, purely insurance against something rattling loose. Snugging them is all that's needed. Unfortunately Toyota spec'd the torque, which is something like 48 in/lbs, and few innocent souls dutifully got out their ft/lb torque wrench, took the heads right off.

 

Regardless of what specifications say, applying that much torque to such small bolts would require gross lack of common sense, or at least lack of experience with physical hardware.

 

In OP's original post for the same headgasket job they had problems reading the torque wrench and tightened the head bolts too tight and we pointed out the measurement test you do to confirm that head bolts are still good and then they never told us if they did the test or even followed up in the original thread and instead started a brand new thread about the cam bolts that they screwed up on too... I'd like to know if they tested the headbolts, but when you try to help people and they ignore you and make everything way more complicated, it's easy not to care amymore about helping 'em.

 

Exactly. Stop for a minute, look at the bolt, and what it's doing.