Head bolts - can i reuse them?

[Apolan]

Hi,
can i re-use my headbolts? Are they streach or normal?

[Mikzu IV]

I re-used them on mine, no problem I'd say.

[jamiemirror]

They are stretch-type, can be reused up to 4 times if I remember well.

[Apolan]

Thanks jamiemirror. Is there a different procedure for tightening them every time around, or always the same?

[gon]

i would measure their length with a micrometer like the manual says before reusing them .... or just buy new ones , they aren't that expensive

[jamiemirror]

No special procedure for used bolts.
In fact you can find Clevite bolts at very low price, I believe in Clevite products and already bought them.

[Rasteirinho]

Like gon said, measure each one of them before using again.

There aren't from the strech type however they are under traction forces all the time which could lead them to fatigue and breakage/loosening.

Don't forget to use the washers between the bolts and the head, otherwise you'll not be able to tight them to the specified torque.

Also take into attention that they have different heights from exhaust to the intake sides.

[Apolan]

hm.. Thanx for the heads up. Haven't really paid that much attention when i was undoing them.

[oldeskewltoy]

4AG head bolts are NOT stretch to yield. The headbolt part number never changed, although the tightening spec DID change. Original torque specification for the 4AG was 44ft-#s done in 3 passes.

From what I was told.... too many techs didn't do the torque in 3 passes... and there were failures. The Toyota engineers developed a method that REQUIRES it done in 3 passes with no short cuts......

I've built 4 4AG engines so far... I've only ever used OEM bolts and 44#s for the head. I set the wrench up to do 22, then 33, and finally 44.

[Rasteirinho]

Well, i think there's two differente torque setups...

I think 4AGE from the AE86 refers 3 passes (X N.m + 90º + 90º) an 4AGE from AT160 and AE92 refers 1 pass (Y N.m, of course Y > X)