Cracked head!!

[cp2295]

Is this repairable with jb weld?? Or if my friend who can weld puts a fat bead on it. It happened while I was torquing the heads down. So it's pretty surface I think. Didn't noticed till I got everything on. Really sucks!!

 

[cp2295]

He'd tig weld btw

 

[adsm08]

You aren't going to JB weld a head.

Where is the damage? Pictures would be good.

 

[cp2295]

Damnit I know.. I was hoping that wouldn't be said but guess I'm going to have to go to the junkyard. What should I look for on a junkyard head?

 

[cp2295]

Which heads are compatible with a 98 4.0?

 

[cp2295]

And are the heads side sensitive or can I get a drivers side head and put it on the passenger side?

 

[RonD]

Have a read here:
http://www.therangerstation.com/tech_library/40rebuild.htm

Best match would be '98-'00 head

No, they are not side sensitive.

 

[KD8KKT]

That sucks, I currently have a situation going on with a broken valve spring I might end-up having to pull my head to fix it I hope not. I would try to maintain the heads on the same side in my opinion just to keep the engine gods happy lol.

 

[cp2295]

And I know not to reuse the bolts but can I reuse the gasket? Hasnt been run or anything obviously, just torqued on. Its a felpro gasket.

 

[Tedybear]

And I know not to reuse the bolts but can I reuse the gasket? Hasnt been run or anything obviously, just torqued on. Its a felpro gasket.

replace.

S-

 

[RonD]

When it comes to head gaskets you shouldn't reuse them once they are compressed.

Head gasket has to hold in 600psi to 1,000psi at the cylinder to head "ring", once it is compressed it will not return to "normal" for re-compression, while it might work for awhile I would just replace it, because of the labor involved in replacing it if/when it does fail.

 

[cp2295]

Dang, alright. I'm pretty positive it happened while I was torquing the head down because I thoroughly investigated each head before changing the valve seals and cleaning them up. It's going across the head (4" inward) and it cracked right next to the #1 cylinder intake valve. I torqued in this sequence: 25' lbs, 54' lbs, another 90 degrees (or 1/4 turn as I look at it). I cleaned out the threads and used new bolts too. Did I do anything wrong or was this head doomed from the beginning? Maybe a hairline crack I couldn't see and then torquing it finished it off?

 

[cp2295]

I was noticing that extra 1/4 turn really torques it on there.. Takes a lot of torque

 

[adsm08]

It was probably there already and you just couldn't see it. It probably would have shown up if you'd had them fluxed.

 

[RonD]

Yes, the switch to TPA method(torque plus angle) takes friction out of the equation when tightening head bolts.
Thread and shoulder friction varies from bolt to bolt, hole to hole and when you get above 50ft/lbs, the TPA method keeps pressure more equal as the point of "torquing" a bolt is to stretch it a specific amount so it has the same holding pressure as the other bolts.

TTY(torque to yield) bolts/method means the bolts are stretched almost to the point of "yielding", failing, this means they will hold better with less variance when heated and cooled.
It also means you shouldn't use them again, or you may find the "yield" point when tightening or after a few heating and cooling cycles of the engine.

Older head bolts were stretched as well but not as close to the "yield" point, but as most older mechanics know, if you were reusing head bolts you made darn sure the threads, on bolt and in hole were clean and oiled, and even then you might have one break on the final torque sequence, lol.
There is nothing quite as unpleasant as having to spend the $50 anyway and then spend another 8 hours for the privilege of NOT saving any money