Replace Head Bolts One At a Time?

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akarilo

akarilo

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Just read...

OK, anybody that's done the head gasket knows that there is a tightening/ torquing sequence used to keep from damaging the head. Would it be safe to attempt to replace the studs one at a time or would that be asking for trouble?

Reason:
I did the head gasket about 10K ago and everything seems to be just fine. Upon reassembly I do remember feeling slightly "iffy" about the way a couple of the studs torqued down, (on the last 1/4 turn). After recently experiencing some "bolt stretch" on a spindle bolt, I can help but think that it possibly what happened on the head bolts. To a much lesser extent with the head bolts though. The hub bolt would have easily sheared had I continued torquing, but the head bolts didn't feel that way. I specifically remember feeling "iffy" on 2 bolts though.

Leave it be? It has gone 10K with no issues. Your opinions?
 
NLXTACY said:
If you are worried about one bolt, replace them all.
Click to expand...

Noted. The question is; opinions on replacing one at a time without pulling the head and replacing the gasket? If that 's not feasible, I will be into another entire gasket job. In that case I would just leave it be, because it might not ever be a problem anyway. Just don't want to create an issue by tinkering.
 
The purpose of the torque pattern is to seat the head to the gasket to the block in an even manner without the risk of distorting the head nor the head gasket. Once the head has been properly torqued, its not going anywhere unless you remove the head bolts. If its one (or two) you are concerned about, and don't want to do another head gasket, then just replace the bolt. The head is already constrained onto the gasket onto the head with the remaining head bolts. I've broken a handful of head bolts over the years. Depending at what point of the rebuild I would just drill and easy-out the offending bolt. Then anti-sieze, drop in new bolt, torque to spec. Then check all other head bolts in their patter. Never an issue.......that I know of :flipoff2:
 
akarilo said:
Noted. The question is; opinions on replacing one at a time without pulling the head and replacing the gasket? If that 's not feasible, I will be into another entire gasket job. In that case I would just leave it be, because it might not ever be a problem anyway. Just don't want to create an issue by tinkering.
Click to expand...


:confused: :meh: :hhmm:
 
NLXTACY said:
The purpose of the torque pattern is to seat the head to the gasket to the block in an even manner without the risk of distorting the head nor the head gasket. Once the head has been properly torqued, its not going anywhere unless you remove the head bolts. If its one (or two) you are concerned about, and don't want to do another head gasket, then just replace the bolt. The head is already constrained onto the gasket onto the head with the remaining head bolts. I've broken a handful of head bolts over the years. Depending at what point of the rebuild I would just drill and easy-out the offending bolt. Then anti-sieze, drop in new bolt, torque to spec. Then check all other head bolts in their patter. Never an issue.......that I know of :flipoff2:
Click to expand...


^^^^ agreed. If you want to replace them, pull and replace one or all of them one at time and there are no concerns.


Mark...,
 
akarilo said:
... Upon reassembly I do remember feeling slightly "iffy" about the way a couple of the studs torqued down, (on the last 1/4 turn). After recently experiencing some "bolt stretch" on a spindle bolt, I can help but think that it possibly what happened on the head bolts. To a much lesser extent with the head bolts though. The hub bolt would have easily sheared had I continued torquing, but the head bolts didn't feel that way. I specifically remember feeling "iffy" on 2 bolts though.
Click to expand...

What you are feeling is plastic deformation. Normally for most hardware, a very bad thing, the hardware needs to be replaced. Some bolts, like the head bolts on the 1FZ, are designed to do this called plastic region fasteners. This is why they tighten with the 90 degree, 90degree, method. So, what you felt is normal.

akarilo said:
... Leave it be? It has gone 10K with no issues. Your opinions?
Click to expand...

akarilo said:
... In that case I would just leave it be, because it might not ever be a problem anyway. Just don't want to create an issue by tinkering.
Click to expand...

My vote would be, leave it alone.
 
I asked the forum once about re-torquing head bolts and everyone was against the idea so I would say don't do the one at a time method.
 
I suggest you flog the crap out of it and drive it like you stole it. It's a forklift motor after all.
 
If no Bourbon was involved, I would leave it alone... ;)
 
Nice feedback guys. If Tools says that is normal I'll leave it be. Probably just paranoia on my part. And no, no Bourbon; the head gasket job required complete sobriety. :D
 
Danimal92sport said:
I'm surprised you guys can say that with such confidence...
Click to expand...

There is this phenomenal document called the FSM that basically tells when to reuse or not reuse a head bolts based on specifications in this said phenomenal document.

So, based on this document it is actually quite easy to tell when one should reuse or replace a plastic region head bolt.
 
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