Cylinder head bolts

Last night***I having touched it since the bolt spun

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8Mud said:

Just for info you can't trust torque wrenches. I've had moderately high end torque wrenches mess up, especially those designed to click skip when they reach to desired torque. They may work fine for many tries and then mess up once.

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I had a crapsman clicker that started overtorquing by 50-lbs, and Sears refused to swap it. This was back when Home Depot accepted craftsman returns and they gave me a nicer Husky clicker in return. I periodically use a fish scale or an analog bathroom scale and check the calibration on my clickers (big socket on the receiver hitch and stand on the bathroom scale or use the fish scale to pull).

So if I torqued the bolt down, backed it off, torqued it down again didnt seem right and backed it off again...does this constititute the bolt being stretched past its life.

trippled said:

You need to use oil on the bolt heads and threads. Anti seize reduces the friction too much. You probably went past the bolts yield and snapped it. The others sound like they have stretched too much already. I would not trust any of the head bolts you torqued with anti seize.

Engine oil works fine for the bolts. Don't need anything fancy.

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So now I'm just going to try cleaning one that had antiseize seeing as though its been toqued down less than the one that I backed off and twice?

Update: Put your bolts in dry people! im not sure when chrysler switched over to torque to yield but third times a charm!

Everythings buttoned up and good i think! Also for some reason I had to bring get to tdc to torque down my rocker arms... I was bending a couple bridges....sticky lifters? Hope this helps someone.Thanks guys!

Mcmadman said:

Update: Put your bolts in dry people! im not sure when chrysler switched over to torque to yield but third times a charm!

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I wish you luck with that.................but it isn't the correct method!

McMadman,

Torque-to-yield (TTY) head bolts are a PITA. They came about in the 1980s primarily for aluminum heads and Multi Layer Steel (MLS) gaskets. ARP sells a head bolt kit for the JEEP 4.0L which when torqued stays within the elastic limit of the bolt and do not yield in stress. So when you release the torque, the bolt length returns to its original length. When torque is released on TTY bolts the bolt has already yielded and stretched and so the TTY bolt is longer and must be discarded. I'd suggest using the ARPs which do not yield and stretch and are therefore reusable. They'll save you a lot of grief and end leaking head gaskets.

Best regards,

CJR

Its in and seems to be holding up. I believe oil on the surface of a brand new machined head was causing tbe bolt to spin but not torque. And next time i will be going with arp.

For what it's worth regarding "Torque-to-Yield" (TTY) head bolts. I did a little more researching on TTY head bolts and found some interesting info. Since the head is the hottest component of the engine, local hot spots in the head that are near a head bolt can reduce that bolt's Young's Modulus of Elasticity (E) significantly and cause that head bolt to yield during normal operation. So after evaluating the equations I found, with moderate temperature increases, the reduction of (E) is significant enough for me, i.e. 20% reduction in (E).

So if your particular head has a "hot spot" that is not being cooled properly near a head bolt, that head bolt can yield more due to it's higher temperature. A yielded head bolt can reduce the clamping force on the head/head gasket and cause head gasket leaks. So in my case, I intend to change-out all my TTY bolts with ARP head bolts.

Best regards,

CJR