Re-torque - Is it necessary?

Hey Guys,

I fitted the cylinder head with a new gasket on my RB30.
I tightened the head bolts as per repair manual instructions.

I've been wondering whether it is necessary to re-torque the head bolts after few hundred km's of running.

If it is either necessary or good practice after fitting a new head gasket, then

Does it mean I need to re-tension the timing belt as well??!!

Adjusting the timing belt tension is a PITA job in RB30 Patrol 'cos the both top and bottom parts of timing cover must come out
along with the crank pulley(harmonic balancer, all drive belts(alternator, AC & power steering), radiator shroud & fan.
An exercise that I would like to avoid unless necessary. :)

Thanx
Dom

I would always recommend re-torquing the head bolts

you DID use new bolts didnt you....
you DID NOT use the old head bolts.........

Quote:

---

Originally Posted by Bigcol

I would always recommend re-torquing the head bolts

you DID use new bolts didnt you....
you DID NOT use the old head bolts.........

---

I am planning to do the bottom end of the same engine in few months time, which includes decking the block surface, honing the cylinders, new ring set and perhaps new big end/small end bearings as well, and even perhaps rebore if necessary.
For that reason, the new set of head bolts I bought for it is still in the drawers. :)
However, the guy who sold(rather gave away) the good cylinder head to me assured the head bolts were 'brand new'.
What he meant was he bought them new and fitted and within a day or so, the bottom end(big ends) of the engine blew up.(R31 Skyline)
So, they were good quality head bolts(genuine) but used once.
In reality, they can be better than the possibly aftermarket set of head bolts that I bought from ebay. :)

I also used anti seize(fine graphite powder) lightly smeared on the threads of the head bolts, just to make sure
the 'cringing' of the head bolts as they are torqued due to excessive friction inside the threaded holes on the engine block won't give
me any incorrect readings on the torque wrench. I also spent an unusual extra time by adding extra steps to torquing steps. :)
I'm hoping all that extra care will yield some favourable results for me. :)

Thanx for the tip about retorquing @Bigcol

What is your opinion on my second question(whether I need to re-adjust the timing belt after re-torquing the head bolts)?

Thanx
Cheers

Quote:

---

Originally Posted by dom14

What is your opinion on my second question(whether I need to re-adjust the timing belt after re-torquing the head bolts)?

Thanx
Cheers

---

is there not a self adjuster on them....

Quote:

---

Originally Posted by Bigcol

is there not a self adjuster on them....

---

By "self adjuster", did you mean the tensioner pulley?
I don't think that pulley can self adjust.
For example I couldn't get in the cam gear after fitting this reconditioned head 'cos it is thicker than the old head which was
actually machined over the limit. I had to remove the timing cover, harmonic balancer etc etc and and get to the tensioner pulley
to loosen up the timing belt a bit to get the cam gear into the camshaft.

So, if I torque more that means compressing the head gasket even more even though it is a fraction of a millimetre.
I am bit concerned the timing belt might loosen up a just a bit enough to upset the cam timing.
I'm wondering whether it is a common practice to re-adjust the timing belt tension after re-torquing a cylinder head.

Tensioner pulley in RB30 engine is just a pulley that presses onto the outside of the timing belt to tighten or loosen it up.
It is manual adjusting one, but PITA 'cos it can't be accessed without pulling the harmonic balancer out, which leads to pulling out
quite a few things along the way. :(

hhhmmmmm

I would have thought there was an adjustment screw or bolt on the outside of the housing near the tensioner....
maybe not
I'm sure they used to have them on the L engines from Nissan........
you maybe right mate.. they could have changed their designs :)


when you re-torque the head - you are only doing it to what you have already torqued it to.... to make sure there has not been any movement
it is just a precaution

Quote:

---

Originally Posted by Bigcol

hhhmmmmm

I would have thought there was an adjustment screw or bolt on the outside of the housing near the tensioner....
maybe not
I'm sure they used to have them on the L engines from Nissan........
you maybe right mate.. they could have changed their designs :)


when you re-torque the head - you are only doing it to what you have already torqued it to.... to make sure there has not been any movement
it is just a precaution

---

You know. Yesterday I thought about drilling a hole(and fitting a removable rubber plug or something of similar) on the timing cover right in align with the tensioner pulley adjustment nut(so I can loosen it by squeezing in a small ratchet(it's size 14mm) in front of the radiator. Then I realized the bastard was 'perfectly' align near the edge of the harmonic balancer, so there is no chance of accessing it that way 'cos the harmonic balancer still gets in the way.
Had they designed the tensioner pulley mounting spot a 1-2cm higher that modification would've been a reality. :( :)

Once the tensioner pulley nut is loosened the moving of the pulley horizontally to loosen or tighten the timing belt can be done by squeezing in a tyre lever or long screwdriver.

BTW, that just gave me an idea. I can fabricate a long 14mm wrench by welding an extension to it and see whether I can access the tensioner pulley nut from the top of the timing cover(after removing the top most part of the timing cover).
Worth a try. :)

Thanx for the idea. You triggered it, even though my brain came up with the possibility. Brainstorming power, indeed. :D