reusing head bolts

[danger_ranger_club]

well i need to get my truck back on the road and i have very little money. my head gaskets are blown but my heads are fine so spending just 20 bucks on head gaskets is very nice.

how safe am i reusing my head bolts and what could go wrong. thanks

 

[BRUTUS_T_HOG]

well if they are torque to yield bolts and you reuse them... every single one of them will shatter after a few thousand miles if not snap off when you tighten them down... trust me, it happened to my dad when he didn't listen

you can always tell torque to yield bolts by the size of their head.. which is small

by the way, torque to yield means the bolts are tightened to their yield point, which is the point of stretch that they will not go back to their original length.

so they become permanently stretched and weakened.. which is why they break after being reused

 

[holyford86]

well i need to get my truck back on the road and i have very little money. my head gaskets are blown but my heads are fine so spending just 20 bucks on head gaskets is very nice.

how safe am i reusing my head bolts and what could go wrong. thanks

don't do it, they are torque to yield

 

[Tedybear]

What could go wrong?

bolts shatter/snap when you try to reuse them.
bolts become weak creating uneven pressure on the cylinder head causing it to warp.

Basically as already stated these bolts are torqued down, and then turned a pre-set amount of something like 1/4 turn or 1/2 a turn. Can't remember which as we did our heads two years ago. This as mentioned, tightens the bolts..and then puts a stretch on the bolts which is how they are designed to work. (don't ask me why the manu's do this---that's just how some engines are made)

It's not worth the headache of attempting to recycle these bolts. They are not to spendy (about 40ish or so bucks). The only key thing to do? Is to ensure the threads in the block are fully clean of any crud that would fool the torque wrench. That is why you'll see in the shop manuals instructions on re-tapping or "Chasing" the threads to remove any old gasket crap and rust. The correct use is paramount in order to get a long lasting seal with the block and head.

Do the job exactly how the shop manual states, and you should be in good shape. Try shortcuts and cost saving stuff (such as recycling the bolts) and you'll be in trouble quick!. And nothing sucks worse then having a head bolt snap off in the block.

S-

 

[Big Jim M]

Well, yes and then again no!

Because the head is hotter than the block most of the time and it also gets hot quicker than the block does the expansion of the block and head is a different amount and in different places.
So if the head was bolted down tightly it might not be tight at different times in the expansion/contraction process....
So here is what happens... The bolt is STREACHED between the threads and the head. This makes them act like a rubber band. So no matter what differences in expansion there might be they will always provide the preferred amonut of pressure on the head gasket! Even if the head gasket SHRINKS a bit over time the rubber band effect will keep the head tightly ot the thinner gasket.

By the way, I can't remember any head gaskets that weren't torque to yield.

I reuse lots and lots of head bolts. But they must be newer than the ones on your 18 year old engine might be. Them 18 year old ones would scare the hell outta me. So, man up, and getcha a new set.
Big Jim

 

[stegomon]

i have put 10,000 miles on my rebuild...no problem with the head bolts yet

 

[danger_ranger_club]

well that sucks for a high school dishwasher now doesnt it. ordered head bolts and gaskets, theyll be here monday. thanks for pointing me right guys!

 

[Angie]

When I rebuilt my 4.0 with the 410 cam I never bothered with new head bolts. just cleaned up the old ones, visualy checked for cracks/wear, then bolted/ torqued them to spec. been 25K kilometers with out a prob. just adding my .02 here.

 

[Psychopete]

I haven't tried to re-use them, but everywhere you look will tell you that those style of head bolts will need replaced (Google it). Some may get by, but the event of a failure is not worth it over trying to save $40. Better safe than sorry IMO.

 

[chazzone]

Wasting money seems like a bad plan for someone who has little of it.

Every resource will tell you that head bolts are designed to be used once, only.

Why would you risk having to spend even more time and money to re-do the job, not to mention the additional damage that could result?

Penny wise and dollar foolish.

-zz

 

[danger_ranger_club]

duuuuude i said i ordered the bolts too. lay off and read posts before you post