Turbo Mounting Studs

[Flattop]

So Ford made the poorly thought-out decision to use non-reusable studs to mount the turbo and to connect the turbo and exhaust. After having to remove the turbo to get it to the machine shop to fix an exhaust stud that got messed up putting on a new exhaust, I decided to roll the dice and replace the turbo mount studs as the manual requires. Luckily, all four came out okay. I have a 2015, and for installation the factory Ford 2015 manual I have says:

1. Install and tighten the new TC mounting studs.
   Torque : 30 lb.ft (40 Nm)
2. Install the new TC gasket.
   Torque : 150 lb.in (17 Nm)
3. Install the new lower TC mounting nuts.
   Torque : 37 lb.ft (50 Nm)

30 lb-ft seems like a lot into an aluminum head. And step 3 makes no sense as there's nothing to torque for the gasket, it's held by turbo and the turbo nuts are 37 lb-ft. I'm wondering if the 150 lb-in might be for the studs (although that seems too little).
Could anyone check a later manual and let me know what it says? Has anyone here replaced those studs?
thanks

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[ihasnostang]

not sure which year range this is for but its the one from cardiag.
i looked at several times too then i saw they go 1) lb-in, 2 lb-ft, 3) lb-in

 

[Buldawg76]

Studs and lower cover bolt are lb-in (12 lb-in = 1 lb=ft) and turbo mounting nuts and upper cover nuts are lb-ft stated above.

BD

 

[Flattop]

Thanks ihasnostang and bd, 12.5 lb-ft is a lot different than 30 lb-ft. Hopefully I haven't stripped out the threads in the head...

 

[Flattop]

I had only gotten to about 25 lb-ft when I stopped because it didn't feel right. Pulled the studs back out today and got a few very small aluminum shavings off the very front of the hole, rest of the threads appeared ok despite being over-torqued 2x. Time to get an updated repair manual.

 

[Buldawg76]

Studs never get tightened to a high torque value compared to bolts of the same size thread. They may use loctite also in some cases, but it is for sealing the threads not to prevent loosening.

BD

 

[RagmopInKona]

So Ford made the poorly thought-out decision to use non-reusable studs to mount the turbo and to connect the turbo and exhaust. After having to remove the turbo to get it to the machine shop to fix an exhaust stud that got messed up putting on a new exhaust, I decided to roll the dice and replace the turbo mount studs as the manual requires. Luckily, all four came out okay. I have a 2015, and for installation the factory Ford 2015 manual I have says:

1. Install and tighten the new TC mounting studs.
   Torque : 30 lb.ft (40 Nm)
2. Install the new TC gasket.
   Torque : 150 lb.in (17 Nm)
3. Install the new lower TC mounting nuts.
   Torque : 37 lb.ft (50 Nm)

30 lb-ft seems like a lot into an aluminum head. And step 3 makes no sense as there's nothing to torque for the gasket, it's held by turbo and the turbo nuts are 37 lb-ft. I'm wondering if the 150 lb-in might be for the studs (although that seems too little).
Could anyone check a later manual and let me know what it says? Has anyone here replaced those studs?
thanks

They are studs, the 37 ft lb is on the stud, not the heads threads, and why they used studs not bolts.

 

[Buldawg76]

They are studs, the 37 ft lb is on the stud, not the heads threads, and why they used studs not bolts.

Studs are 150IN-LBs into head. turbo flange nuts are 37 FT-LBs to hold turbo to head.

BD

 

[RagmopInKona]

Studs are 150IN-LBs into head. turbo flange nuts are 37 FT-LBs to hold turbo to head.

BD

Yes, so 150 INCH lb's on the head threads, and 37 FOOT lb's on the stud threads.
A whopping 12.5 foot lb's on the heads threads.
Again it is why they used studs and not bolts

 

[Buldawg76]

Yes, so 150 INCH lb's on the head threads, and 37 FOOT lb's on the stud threads.
A whopping 12.5 foot lb's on the heads threads.
Again it is why they used studs and not bolts

Studs hold better clamp loads than bolts do.

BD

 

[RagmopInKona]

Studs hold better clamp loads than bolts do.

BD

Also don't stress the heads threads as much.

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