head bolts stretch or not?
#22
#24
#25
Head bolts
My mechanic decided to go with Time Serts insert kit and bolts. because of stripped threads on the first hole we tried. We stopped and evaluated the best way. Did not go with studs. We bought them from Kimball Midwest. We are in Daytona Beach, Florida
Mechanic was very happy. Cost was approx.$200.
Mechanic was very happy. Cost was approx.$200.
#26
Timeserts are the best - Once you use them helicoils seem so inferior. Can't beat helicoil for the price and availability, but for something like these threads, timeserts is the only solution.
Studs are still better than the bolts, but at least driving the bolt into the steel timesert will give better results than driving the bolt into alloy.
Studs are still better than the bolts, but at least driving the bolt into the steel timesert will give better results than driving the bolt into alloy.
#28
It's not the alloy threads that are the problem, its the poor surface finish on the bolts that results in applied torque not resulting in increased clamping. The poor finish will dig into the soft alloy and resist rotation, in addition to the simple friction of alloy/steel. Steel against steel will result in less "digging in" - meaning you are looking at steel against steel friction as the major contributing factor. Timeserts also have a very good thread finish - all of which helps - only thing to check is that the "installed bolt height" is sufficient before the male thread bottoms out into the timesert wedge (at the end of the insert) - it might be neccesary to shorten the bolts a little.
All of these are still reasons why studs, specifically the ARP 124-4003 kit is far superior than anything else, because most of the turning force is applied to tension in the fastener, courtesy of two very well machined and controlled thread forms (stud and nut) along with hardened washers; all of which minimise friction.
BTW - There are mony others (and myself) who believe the 80lb ft figure for the ARP's for these engines is a little too high, and might do more harm than good. On the V8 owners forum, where all they talk about is the Rv8, everyone suggests 60lb ft, done over two, maybe three equal steps (20, 40, 60 or 30, 60). There are several reasons - but the main obvious one is that the stud/nut interface is a fine-pitch, wheras all bolts use a course pitch. This alone means that (negating friction or thread form) an applied torque in a fine pitch thread results in increased clamp force as compared to a coarse pitch thread of the same size. Then you have additional factors such as the ARP moly lube, the excellent thread form and the hardened, ground washers - and it's easy to understand why a high percentage of the torque you are applying results in increased clamping (unlike bolts)...
All of these are still reasons why studs, specifically the ARP 124-4003 kit is far superior than anything else, because most of the turning force is applied to tension in the fastener, courtesy of two very well machined and controlled thread forms (stud and nut) along with hardened washers; all of which minimise friction.
BTW - There are mony others (and myself) who believe the 80lb ft figure for the ARP's for these engines is a little too high, and might do more harm than good. On the V8 owners forum, where all they talk about is the Rv8, everyone suggests 60lb ft, done over two, maybe three equal steps (20, 40, 60 or 30, 60). There are several reasons - but the main obvious one is that the stud/nut interface is a fine-pitch, wheras all bolts use a course pitch. This alone means that (negating friction or thread form) an applied torque in a fine pitch thread results in increased clamp force as compared to a coarse pitch thread of the same size. Then you have additional factors such as the ARP moly lube, the excellent thread form and the hardened, ground washers - and it's easy to understand why a high percentage of the torque you are applying results in increased clamping (unlike bolts)...
#29
It's not the alloy threads that are the problem, its the poor surface finish on the bolts that results in applied torque not resulting in increased clamping. The poor finish will dig into the soft alloy and resist rotation, in addition to the simple friction of alloy/steel.
If using other bolts that are torqued, then there are torque tables to adjust for material types, dry vs lubed, etc.
#30
I could be on crack here, but...
I swear I just read some guy who has done a bunch of head gaskets talking about how he believes the torque sequence is wrong? I believe i found the link in a DWeb thread.
I cant remember what his reasoning was (maybe it was because of the different lengths of the bolts?) but he said his sequence and torque has been bulletproof so far.
Just food for thought, but Ill keep trying to find the write-up.
I swear I just read some guy who has done a bunch of head gaskets talking about how he believes the torque sequence is wrong? I believe i found the link in a DWeb thread.
I cant remember what his reasoning was (maybe it was because of the different lengths of the bolts?) but he said his sequence and torque has been bulletproof so far.
Just food for thought, but Ill keep trying to find the write-up.