How hard is it to snap an F-Head head bolt???

OK so tonight I went out to put the head gasket on, and drop on the head. All went smooth and with a good light and a tester rod in some holes I could tell that I was in good shape as far as alignment of the gasket.
So I start putting in headbolts.
I recall that some of these things were BEARS to get out.....but now that they are going back in, some go in very nicely smoothly with resistance but easily wrenchable (none are totally snugged down yet by the way, no uneven pressure on anything, all bolts still up a little)

Some bolts however are absolutely KILLING me trying to reinstall them. They get about four or five rotations in and then I would need a breaker bar to keep going!(didn't do that yet!) chainsawguy
So, is something wrong?
Interestingly these are all on the outside holes, three on left two on right. I really cranked one then feared I was stripping/flattening the threads so I pulled it back out but the threads looked fine (at least on the bolts, cannot speak for the BLOCK!) Has something icky hardened in the block threads?

How hard is is to snap one of these bolts? Anyone done it?
Would using a breaker bar be a bad idea (my wrench is a 3/8 drive only like 7" long if that...)
Is this "normal"? Do I just crank em down????

Any advice welcome!!!!!!! I would prefer to not have to remove and re-align the head, LOL! Damn thing is heavy and it is in there so sweet...!

 

They shouldn't go in that hard, it's probably from dried gasket sealant. Since some of the bolts go into the water jacket (don't remember which ones) they probably had gasket or RTV sealant on them. It would be a good idea to clean the threads with a thread chaser. A tap will work if you are careful.

 

That is precisely why they make torque wrenches...

And definitely clean the internal threads with a tap, or you'll have no idea if the gasket is being compressed properly.

But you'd have to pull more than a 7 inch wrench to break one. You'd probably break the 3/8" drive first.

 

ALWAYS clean head bolt holes with a tap or thread chaser before reassembly to avoid this issue. You probably have sealer, rust, or burrs on the threads causing this issue. Also check the bolt threads as well. Cleaning them with a wire wheel is standard and good practice. As was said make sure you use a torque wrench on them and torque them in steps. Typically the threads should be lubricated on assembly except where they go into a water jacket. Then some sealer like aviation form-a-gasket works well and acts like a lubricant if you torque immediately.


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If your head bolts dont go in easy they wont torque correctly, and getting a stuck broken bolt out is not fun at all especially if its a head bolt.

 

Should be replaced with new ones anyway. They will only stretch so far, and after 50 some years can be fatigued.

 

As mentioned above I chased mine out before I put it back together.

 

agree with every one else, clean the threads and might even want to put a few drops of oil on them.

 

Yeah cleaned the bolts, even numbered to make sure each went back into the same holes, and dipped in a pinch of oil... and I do not think these are original 50 year old bolts. Although..........
Anyway, gonna remove AND try to clear out the block holes and start over.

I do of course have a torque wrench, I just hadn't gotten that far yet!