Should I Re-torgue My Head Bolts??

[ftm1776]

1991  1.6 Diesel Non-Turbo, Engine Code ME; 293,000 miles.

I would like to check my head bolt torques and/or just re-tighten them to torque spec.
I have never done this and would just like to be sure that they are correctly tightened.

I am the original owner so I have a fairly good account of the engine history and usage.

The engine is running just fine. Starts easily, minimum oil usage; compression ok, 46 mpg over 1500 miles.

Many years ago, say 10, I had some work done that required that the head be removed and replaced.

Can I check, i.e., retorque my head bolts??? I did not do that after the head work was done so many years ago.
I assume that this engine originally had the Torque-to-Yield, "stretch" bolts. I can't say for sure what's in there but assume that  they are the 12 mm size.

So should I check/re-torque the bolts?? How and to what torque??? If they are not tight enough would I be experiencing some adverse symptoms??? Should I leave well enough alone?? Is there a risk of snapping them off??

Comments, please.

[Hdriven]

I'm definitely no expert in the diesel world, but my experience with many other engines wants to say no. I would not torque them down especially if there is nothing wrong with it. Maybe, I would check the torque if they were arp head studs but not on stretch bolts. This is just my opinion though.

[burn_your_money]

I'm definitely no expert in the diesel world, but my experience with many other engines wants to say no. I would not torque them down especially if there is nothing wrong with it. Maybe, I would check the torque if they were arp head studs but not on stretch bolts. This is just my opinion though.

X2. It ain't broke

[jmaddocks]

x3

Pretty cool that you're the original owner.  I am *almost* the original owner of my Corrado (bought it in Oct '91, 4 months old with 4k miles), which means I have no one to blame but myself for its dings, scratches, and other battle scars.

[Rabbit79]

x4
Classic case of 'if it ain't broke, don't fix it'. Especially if it's been giving good service for 10 years.

[vanbcguy]

x5 - you can't retorque stretch bolts since there is no torque setting.  They are torqued till they yield, meaning additional tightening won't do anything but make them yield more.  Well it might make them break....

[ftm1776]

Sounds unanimous.......and, the less work, the better!!!

if they were arp head studs but not on stretch bolts

What are "arp" head studs???

x4
Classic case of 'if it ain't broke, don't fix it'. Especially if it's been giving good service for 10 years.

Times 2.3....23 years of excellent service....They don't make them like this any more.....simple !! Worth any money I have to put into it too !!

They are torqued till they yield, meaning additional tightening won't do anything but make them yield more.  Well it might make them break....

Yes, stretchy, stretchy.....harden, harden......snap !!! I read on another posting that they did this to facilitate mass assembly...easier than having to torque to an exact spec.

[745 turbogreasel]

Sounds unanimous.......and, the less work, the better!!!

if they were arp head studs but not on stretch bolts

What are "arp" head studs???
Reusable non stretch expensive fasteners made  by 'American Racing Products'

x4
Classic case of 'if it ain't broke, don't fix it'. Especially if it's been giving good service for 10 years.

X5

They are torqued till they yield, meaning additional tightening won't do anything but make them yield more.  Well it might make them break....

Yes, stretchy, stretchy.....harden, harden......snap !!! I read on another posting that they did this to facilitate mass assembly...easier than having to torque to an exact spec.

For me they always seem to  turn a little easier right before they snap.

[vanbcguy]

Yup, TTY bolts provide consistent clamping force - when the bolt starts going plastic it provides exactly the clamping force that the particular material can exert, rather than relying on clamping due to measuring how hard it is to turn a bolt in a hole.  It's much easier to consistently provide exactly the same results using TTY fasteners, the downside is they are single use.

[fatmobile]

Yes, you can retorque them.
Use a beam style torque wrench so you can see when they start to stretch.
 Back them off 30 degrees so it is a dynamic reading instead of a static reading.
Which means you want the wrench to be moving when you take the reading, it can't be stopped that would read static friction.
 Watch the beam, it will increase to about 90-95 and stop rising as it turns. Because the bolt has begun to stretch. Time to stop.

 Great way to do the 100 mile retorque because it stops you when the bolt starts to stretch, not after some random 1/4 turn.

 Some folks think that loosening one bolt at a time can cause the head gasket to let loose.
 Maybe it can. I was worried about it when I swapped my 1.5 headbolts to ARP studs one at a time. But even after 35psi spikes and all the backpressure from a closed-vaned VNT 15 it never blew.
A little quantum-man research.

[ORCoaster]

A little quantum-man research.   Better be careful you might get run out of town with that sort of stuff. 

[theman53]

A little quantum-man research.   Better be careful you might get run out of town with that sort of stuff. 

Only if you are repeatedly warned and dumb enough to continue.

[ORCoaster]

LOL,   But I have a point to make and you are just not accepting it.  Surely you can see my point?

[theman53]

LOL,   But I have a point to make and you are just not accepting it.  Surely you can see my point?

Nope. Unless you mean that someone here will get banned if they are warned, put on temp ban, let back on with more warning, and continues behavior. This place is better since he is not here. Please explain fully, pm me if needed as the thread needs to continue.