TTY bolts
11-01-2005, 04:41 PM
#1
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TTY bolts anyone know the theory behind the tty bolts (head bolts)
Im having a hard time believing that +X degrees
and drawing lines on bolts is more accurate than
my tq wrench.
Im having a hard time believing that +X degrees
and drawing lines on bolts is more accurate than
my tq wrench.
11-01-2005, 09:12 PM
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Really not much "theory". They're inexpensive, mass-produced, consistent fasteners. They clamp consistently at a known stretch. It is possible for the stretch to be highly consistent because, after 1st pass initial torquing, the additional rotation in degrees is a highly accurate method of clamping. 55 degrees (I'm using this figure just as an example) is 55 degrees. Period. You aren't subject to small variations in torque wrench performance or "feel". When the pointer on the degree dial reaches 55 degrees, that's it.....the fasteners are stretched about as perfectly identical to one another as can be. But, as mentioned above, once stretched to spec, you're done. Remove the fastener and you have to throw it away...it cannot be reliably torqued to stretch specifications again.
A fastener like an ARP, which uses higher quality materials, are centerless ground, and undergo more rigid quality standards, are much more expensive to produce, but they can be re-used.
Price a GM OEM TTY fastener kit, and then price a fastener kit made by ARP.
A fastener like an ARP, which uses higher quality materials, are centerless ground, and undergo more rigid quality standards, are much more expensive to produce, but they can be re-used.
Price a GM OEM TTY fastener kit, and then price a fastener kit made by ARP.
11-01-2005, 10:39 PM
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I think it's all bs 
I never heard of a head lifting due to improper bolt tightening. My buddy put his heads on with stock bolts and jacked up the thread pattern on one side, hasnt had a problem 10k later.
I never heard of a head lifting due to improper bolt tightening. My buddy put his heads on with stock bolts and jacked up the thread pattern on one side, hasnt had a problem 10k later.
11-01-2005, 10:49 PM
#5
Pretty sure the additional degrees of turning put the bolt into a "failure mode" that is easy to predict b/c of the properties of the bolt material. But once it has stretched out that far, it cant be used again.
As mentioned before, its good for mass production; i don't think they are better than quality reuseable bolts installed with the proper torque
As mentioned before, its good for mass production; i don't think they are better than quality reuseable bolts installed with the proper torque
11-02-2005, 11:52 AM
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whats the reason for the measurement being in degrees rather than foot pounds
I see what youre saying about 55* is 55*
but what if 55* on one bolt =70ft/lb
and a different bolt 55*=75ft/lb?
how would it be to to double check behind the degree method with a tq wrench?
I see what youre saying about 55* is 55*
but what if 55* on one bolt =70ft/lb
and a different bolt 55*=75ft/lb?
how would it be to to double check behind the degree method with a tq wrench?
