2.9L & 3.0L V6 Tech General discussion of 2.9L and 3.0L V6 Ford Ranger engines.

New head bolts breaking when torquing

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Old 07-03-2016
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New head bolts breaking when torquing

Title says it all

2001 3.0 engine
Fel pro head bolts are new

Sequence followed correctly
Torqued to 59
Loosened
Toques to 34
Turn 90°
Turn another 90°

I am on the passenger side head
The first bolt broke on the #2 when going to 59

So I went and got another set
Went slower and got it to go to the second round of 90° turns
It then broke again....same #2 bolt

One problem is that the inside bolts don't reall want to torque at all. They just stretch until breaking point. I never can get a click on them. The outside spark plug side bolts will torque down.

Another procedure skipped the 90° turns and said to go to 68
I checked most of them and they were at 68

The Taurus engine shows much lower torque specs as do some of the other ranger 3.0

What's going on here and what is the correct spec?

-

Of the lower numbers work I'd go that route because I keep busting them
 
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Old 07-04-2016
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What it might be

I'm seeing two different torque specs
59
Loose
40
Turn 90°
Turn 90° again

Then I see
37
Loose
22
Turn 90°
Turn 90° again

My engine came from a 2001 ranger
My block stamp says 2002
My ranger is a 98


These are transition years
They went to longer head bolts in 2001
I wonder if the longer bolts use the 2nd method and im breaking them because
The longer bolts are meant to be 37ft/lbs instead of 59 ft/lbs


-


However: both of these methods and specs are all over the Internet.
The longer bolts on the lifter side of the engine never click the torque wrench at 59.
They do at 37
 

Last edited by Glhx; 07-04-2016 at 07:06 AM.
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Old 07-04-2016
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Welcome to the forum

All the head bolts should be the same length.
Yes in 1999 the Vulcan 3.0l got longer head bolts, but all are the same length, just longer than 1998 and earlier.
Your engine is a 2001 3.0l so will use the longer bolts
But it is very easy to tell which head bolts are correct
In 1998 and earlier the threads in the block for the head bolts came right to the surface of the block.
In 1999 the threads are recessed in the block
Go here, about 3/4 of the way down the page you will see picture of recessed threads: Ford Ranger II 3.0 liter Engines

Recessed thread blocks use the longer bolts, heads are exactly the same

After head is in place
Tighten each head bolt to 37ft/lb in correct sequence

Then loosen each head bolt, in sequence, 1 full turn(360deg)

Now tighten each head bolt to 22ft/lb, in sequence

Then tighten each head bolt 90deg, in sequence

Then tighten each head bolt 90deg, in sequence again


Make sure threads are cleaned out, oil a head bolt and with head removed run the bolt down all the way, as far as it will go, no need to torque it just make sure if goes down smoothly.
If the same bolt broke twice then you could have bad threads in that hole, may need to run a tap down it to clean it out

Also test your torque wrench
Google: testing torque wrench with a vise

I had one that lost calibration and caused me some problems
 

Last edited by RonD; 07-04-2016 at 11:19 AM.
  #4  
Old 07-04-2016
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So the 59 spec is for the earlier shorter bolts
And the 37 is for the longer bolts.

All my bolts are the same size.

Will check the threads again.
I did chase all of them

Question about the head gasket
It's is new but was torqued to 68
Should I replace it?
 
  #5  
Old 07-04-2016
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No, head gasket will be fine, it is not fully compressed until engine is started and gets up to operating temp, the head metal(and block) then expands and gives it the final seal.

And I think I see your problem with the numbers, or with the way other people posted the numbers.

3.0l Vulcan engine has been around since 1986, earlier engines did NOT use TTY(torque to yield) head bolts, so no 90deg turns, just straight torque numbers
Torque to 50ft/lb
Loosen 1 turn
Torque to 37
Torque to 68
THE END no 90deg stuff

All the TTY bolt 3.0ls use the same:
37
loosen
22
Then 90deg
and 90deg again


TTY bolts are better at holding but do need to be replaced each time they are fully stretched.
The main reason for using them however is cost, well cost savings for manufacturer.
Constantly calibrating torque wenches at assembly plants is expensive and just never was all that reliable when machines took over.
But 90deg rotation on an automated machine is consistent, and the 37ft/lb, and 22ft/lb are not all that critical, the 90deg and 90deg are
 

Last edited by RonD; 07-04-2016 at 07:26 PM.
  #6  
Old 07-27-2016
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That explains it
I did the 37/22 90° 90° and had no trouble

It's good to know why they switched to tty bolts. Makes sense
Cost was $50 for those bolts but I did replace them.
 
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