possible blown head gasket UPDATED WITH MORE PICS

[ScanmanSteven]

Ouch! Do you think there's any possibility that you forgot to torque the bottom set? What about the other bank? Don't really understand the broken bolt, even being loose one would think the top one would break due to the flexing.

 

[m_m70]

I can say for sure that the lower bolts got torqued the same as the uppers. The sequence won't allow you to do just the tops or just the bottoms. I'm just surprised that the bolt is broken and even more surprised that the 2, 3 and 4 cylinder have any compression. Not looking forward to removing the busted bolt. The only upside I see for that is it's only been together or around 500 miles so nothing is corroded together.

 

[DirtDonk]

Would be worth a call to ARP too by the way. I don't know if they officially do anything about that kind of stuff (racing, performance, and many unknowns with non-pro builders, etc), but as a manufacturer, at the very least I think they'd want to know about a failure. And maybe they're just the ones in a position to help?
At least with some possible suggestions.

Point them in the direction of this thread even.

I'm not aware of any V8 engine of this type that requires you to go back and re-torque the head bolts. Doubt whether their stuff is any different from a fastener perspective, but maybe it's an aluminum head thing? Looks like you have the required washers under the bolt head. Are they flat on both sides, or is there a beveled side?
Could they have been installed upside down?

Paul

 

[73azbronco]

No need to retighten any head bolt, factory or ARP. That's why they have you tighten in a three stage process.

Very odd to bust an ARP? Even stranger.

 

[Broncobowsher]

I just pulled up the ARP head bolt instructions. 70 Ft-Lb is correct.
I would give ARP a call and see what is up. Sounds like everything was done right. See if they can shed some light on this. I am really surprised to hear of the ARP bolt breaking like that.

I am 98% sure that the broken part will back out with a little gentle persuasion with a little pick just unscrewing it by hand.

Next up would be taking a digital caliper and start measuring everything. Depth of the bolt holes in the block, thickness of the head, thickness of the alignment dowels, depth of the alignment step in the block and head. Just measure everything to make sure nothing bottomed out.

And which head gaskets did you use?

 

[m_m70]

I'll call ARP tomorrow. Agreed they most likely won't do anything for me but to here what they say may have caused this other than bolt failure will be interesting. Still trying to figure it out in my head%).
Hoping the head itself isn't trashed. If I could get away with it with the wife I'd just throw a crate motor in it and move on. ;D;D;D;D

 

[Rustytruck]

I would check and make sure the head is not sitting high on the head dowels

 

[m_m70]

I used the torque specs for the TFS heads which were stage 1@30#, stage 2@40#, stage 3@50# and final 65 to 70#.
I'm really not worried about getting the broken end of the bolt out unless it did bottom out.
I used the Fel-Pro 8548PT-2 Gasket which was recommended by TFS.
It's going to be a while before I can get to this. Caught me totally off guard as most Bronco projects do.

 

[broncnaz]

The newer heads appear to have a different torque than the older heads as my older heads also had the upper and lower specs that were different. But the new ones say all at 70.
While it is odd that the bolt broke but they probably dont test every bolt they make. Id contact ARP let them know.
They have a chart on ARP's website that may tell you how your bolt broke.

 

[Rustytruck]

Arp should be able to test the broken bolt to verify hardness. You will know if the the bolt was bottomed out.

 

[m_m70]

OK so got the head off tonight. 4 out of 5 bottom head bolts are broken. Top bolts were fine. What really sucks is 3 bolts are broken inside the head around an 1/8" deep.
See pics of gasket and head below. torched number 1 cylinder. If you look closely at the gasket it appears that 2 and 3 cylinder were starting to degrade as well. What could cause this?

 

[BRONCROB]

Man those valves sure are clean

 

[broncnaz]

Well broken head bolts allowing leakage when each cylinder fires off is what cuases that. While one broken bolt is bad multipule broken bolts is not a good thing Id definetly get ahold of ARP.
Id be getting a new set of head bolts and replace all of them. ARP may have had a bad run of bolts and you got unlucky.

 

[m_m70]

got a hold of ARP and they seem to think the bolts were over torqued. I have to disagree but hey I'm not a mechanic. I was a machinist though for over 20 years and know how to torque a bolt to spec. I am sending the broken bolts back to the so they can get a better idea of what happened. They are sending me a new set. Going to pull the other head and replace both gaskets this week. hoping broken ends come out of the block somewhat easily.%)

 

[broncnaz]

If they were broke off near the head of the bolt and the diameter of the bolt is not necked down which appears to be the case I would say they were not over torqued. As overtorquing usual results in necking down then breakage.
Unless the bolts bottomed out they should come out without to much fight.

 

[73azbronco]

I'd worry the bolts bottomed or they were over torqued. Did you chase the bolt hole threads before installing? That or bad wrench, My first incident with a bad torq wrench was severe overtorque of a bolt. They don't fail nicely when they go.

 

[m_m70]

I installed the heads a few months back. my torque wrench could be off I guess. I'll be able to tell if the bolts bottomed out as I now have 4 broken pieces to get out. I put a straight edge on the head and it doesn't seem warped which surprises me. The motor never seemed to get hot though.

 

[73azbronco]

I'm surprised you didn't find this by huge water leaks... A motor which isn't making heat wont overheat

Did you chase the bolt hole threads? If not, will probably want to after you remove the busted ones, then without the head in place, make sure the bolts go in further than needed by hand.

 

[m_m70]

no water leaks at all. I did not chase the threads before install. My fault but as you said, I will next time! And run all bolts down to make sure they don't bottom out.

 

[savage]

When you put the washers on the head bolts ,did you make sure the chamfered edge was up.