03-26-2009, 08:45 PM
does anyone know if the bolts that hold the turbo to the pedistal can be reused?
03-26-2009, 09:08 PM
I think it depends on how many times you have removed and re-torqued them. Like any bolt, the threads will stretch some each time.
I would feel comfortable with re-using them twice over the original installation.
03-26-2009, 09:25 PM
Ford's specs for both the pedestal to block and turbo to pedestal is 18 lb-ft.
Garrett's specs for the turbo to pedestal is 35-37 lb-ft.
The last time I installed my GTP38, 18 on the turbo to pedestal leaked a little and 35 fixed it. Others have stated the opposite.
03-27-2009, 04:22 AM
I've had mine off four or five times, never even put a torque wrench on them. Just tightened them up really good. No leaks yet.
03-27-2009, 06:08 AM
just make sure they are tight and the o-rings are in good shape (new). had mine off a bunch of times. no problems so far
03-27-2009, 01:45 PM
According to the engineers (No engineer here so I can barely get my head around most of this stuff), The whole idea of torquing a bolt is to 'stretch' it so it will stay in place. From trying to get through some of the studies I have read (ever try reading a telephone book?), during the process of torquing a fastener there are radial and torsional stresses placed upon the bolt. These stresses begin the process of eventual metal fatigue.
On the turbo pedestal, you have additional stresses of heat expansion and contraction due to the close proximity of the exhaust turbine housing and downpipe. There are numerous automotive fasteners that are considered "consumable", meaning they should only be used once. I doubt if the turbo bolts fall into this category.
Due to bolt stretch and the possibility of metal fatigue failure, I said that I feel "comfortable" with only using the bolts a couple of times after the original install, that is not to say that you will or won't get many more uses out of them before the bolts fail. I just don't want it to happen when I am 500 miles from home.
One other thing I found interesting is the use of bolts and washers over the use of flange bolts like we find on the pedestal bolts:
"Do not use plain washers; their use can result in relative motion to change from the nut to washer, to washer to joint surface, during tightening. This as the effect of changing the friction radius and hence affects the torque-tension relationship. If, because of excessive bearing pressure, a larger bearing face is required, thought should be given to the use of flanged nuts and bolts."