Installing new head bolts. Torquing to 15 ft.... Set all bolts in counterclockwise, gradual tightening. Used a 4-5" extension on torque wrench. Could *NOT get torque wrench to click..... kept tightening down... No clicking on any of the 10 bolts... kept tightening, and then the middle bolt f-cking snapped off...

I bought the bolts from Rimmer Bros... The original ones they sent me showed up with rust (not a great initial impression) and to their credit they did replace them... did I buy junk or is this something I did wrong?

ERR2944 is the part
CYLINDER HEADBOLT 7/16 UNC X 3.78 GENUINE


bolts that the company replaced:

 

Sounds like your torque wrench is messed up. 15ft-lb is easy to do with one hand and a 6 inch ratchet handle.

 

I used it earlier in the day to 40 ft lbs with no issue on all of the bolts on all of the exhaust manifolds to the heads and it seemed to work fine???

The 15 ft lbs didn't feel the same - felt like I was over tightening the bolts except they kept moving every time I used the wrench except no clicking... I agree, the 15 ft lbs should have been easy peasy and not felt incredibly harder than the 40 ft lbs.

 

Before you installed the HG's and bolts did you clean out every single bolt hole with air to make sure no oil, coolant, or misc debris was present? 15LB is like nothing and shouldn't have required much at all to obtain.

 

So, this is where cheap torque wrenches can cause issues IMHO. That is not a dig, I love my HF sale torque wrenches and they do great for what I generally need.

But...

On my 1/2" drive wrench, the clicks get louder as torque settings go up. At 10-15 lbs I have to carefully watch the head of the wrench cause I often don't hear the click.

I just don't see any way you broke that bolt at only 15 lbs. A piece of pasta that size would take 20-30 lbs to break. Either you wrench is completely borked or it torqued over so quietly you didn't notice. My money is on the latter, especially with an extension in the mix.

 

Torque wrenches have what's called a "working range" or "working percentage". Meaning that they do not work from 0-100% of their range, but more like 20-100%. And that's only if they've been properly calibrated, and stored with no tension, or completely unwound. If it's a manual wrench stored under tension, they will be permanently inaccurate. Same if they are ever used to loosen a bolt, they are only designed to tighten, even if they have a reverse switch, don't ever use it to loosen a bolt.

Google this term: torque wrench working percentage

15ftlbs is not within the accurate working range of a torque wrench with any larger than a maximum of 100ftlbs or so. I have multiple torque wrenches of different sizes specifically for this reason.

Also, if you snap a head bolt in the block of a aluminum engine, like the LR 4.6, you will likely have damaged the threads in the block, or cracked the block itself. Fingers crossed you'll be ok, but I would definitely check before trying again... good luck

 

15 ft/lbs on a 1/2" tq wrench is like hanging a 5 lb weight off the end. Definitely an issue with your tq wrench.

 

Big question: is there enough thread sticking out of block to remove the bolt easily?

 

I 100% agree with all the above. You went way higher than 15ft.lb. I use cheap torque wrenches at home, but I check them for calibration every time I use them with an electronic fish scale.

 

Thanks as always... Helpful info... Definitely something funky with my torque wrench.... Won't be using it again.... I took the head off, and the bolt half that snapped was in there pretty loosly....I hand twisted out - is that normal? Not sure what to make of it. Could I have bottomed it out? Do I need to replace this gasket?






Blew air into all the holes before I installed the bolts multiple times.... Repeated after taking head back off.... The rear upper bolt hole was weeping dark oil (didn't do this when I installed)... I don't think it was from the dip that I did right before first attempt at install (bolt to the right of the copper circle in pic below- driver's side top rear bolt). However, I'm hella confused why the rear oil delivery holes on the heads don't have a mate on the block (circled in green)... Can someone please explain this to me... Confused.



This is the oil delivery hole that I don't see a mate to on the block.... Confused