Newly Discontinued parts
10-24-2007, 02:54 PM
#1
Burning Brakes
Thread Starter
Newly Discontinued parts
Just an FYI.
Gm has just recently discontinued the following parts:
Head Bolts
Timing chain tensioners LH & RH
Timing chain tensioner housings LH & RH
Map sensor hose
Oil pan drain plug & washer
Gm has just recently discontinued the following parts:
Head Bolts
Timing chain tensioners LH & RH
Timing chain tensioner housings LH & RH
Map sensor hose
Oil pan drain plug & washer
10-24-2007, 04:13 PM
#3
Team Owner
I don't believe that is true - regardless, there are now Head Studs that are vastly superior.
Also - I'm sure Kurt will be working on producing replacements for all these parts. BTW Kurt - thanks for the updated bearings - the old ones are on the way back to you!
Also - I'm sure Kurt will be working on producing replacements for all these parts. BTW Kurt - thanks for the updated bearings - the old ones are on the way back to you!
10-24-2007, 04:40 PM
#4
Race Director
10-25-2007, 08:03 AM
#5
DDSLT5 is correct, the head bolts can be reused IAW the service manual. The torque on a bolt that can be reused stretches/deforms the bolt elastically which means when the bolt is removed, all dimensions (length and diameter) return to original and the bolt retains its' full load carrying capabilities. Head bolts that are one time use only (or any other bolt that is one time use only) are known as "torque-to-yield" bolts. You torque them to a certain spec and then turn them an additional amount which causes the bolt to yield meaning you've entered the plastic zone of deformation...when you remove the bolt, all dimensions do not return to original. When a bolt enters the plastic zone, it causes a "necking down" effect which reduces the diameter of the bolt while the length increases. The increase in length is not the problem, the reduction in diameter causes a decrease in the area of the cross section of the bolt so while the strength of the steel (in PSI) remains about the same, the reduction in area causes a decrease in the load carrying capabilities of the bolt. So if you were to reuse a torque-to-yield bolt (now it has been stretched to yield twice), it may fail in service. Like this:
You can see the "necking down" of the diameter before failure.
I think Lingenfelter and Rippie were saying LT5 head bolts can be reused as in they aren't torque-to-yield bolts. I can't imagine them ever saying to reuse any torque-to-yield bolt.
You can see the "necking down" of the diameter before failure.
I think Lingenfelter and Rippie were saying LT5 head bolts can be reused as in they aren't torque-to-yield bolts. I can't imagine them ever saying to reuse any torque-to-yield bolt.
Last edited by glass slipper; 10-25-2007 at 08:12 AM.
10-25-2007, 04:54 PM
#6
Race Director
A bolt that is in this range is the conecting rod bolts and the camshaft timing gear bolt these are they torque to yield bolts that require an addition turn past the torque of lets say 80-85 degrees those are not to be used again.