Motor mount re-assembly question

[Frodo]

Follow-up question:

Has to do with replacing the bolts attaching the yoke to the body (these being the ones that sometimes come out nut + stud and sometimes nut followed by stud):



Bentley says to torque it to 48 ft-lb, but I assume that's just for the nut itself. The studs (with the 7 mm head on them) I would think you would just tighten until they're snug, then crank the nuts to 48. Right?

[san rensho]

Originally Posted by Frodo

Follow-up question:

Has to do with replacing the bolts attaching the yoke to the body (these being the ones that sometimes come out nut + stud and sometimes nut followed by stud):



Bentley says to torque it to 48 ft-lb, but I assume that's just for the nut itself. The studs (with the 7 mm head on them) I would think you would just tighten until they're snug, then crank the nuts to 48. Right?

NO! You have to torque the studs into the frame at 48 ft-lbs. Then torque the nuts onto the studs at 34 ft-lbs. If the studs aren't torqued, thay can pull out of the frame, goobering the threads in the frame. Then you will be in a world of ********************.

[Frodo]

So you can put 48 ft-lbs of torque on those little 7 mm heads without chewin' them up?? And, regarding torque values, Bentley says

Engine yoke to body 48 ft-lb

They don't distinguish between the nuts and the studs.

[Pat]

Yoke to body = 48
Nut to stud = 34

[Frodo]

You guys are confusing me...

Regarding torque values, this is what Bentley recommends, in full:

Engine mount to engine 34 ft-lb
Engine yoke to body 48 ft-lb
Engine yoke to engine mount 48 fl-lb

Now, what I've been talking about is the second in the list..my only question is whether they're recommending 48 ft-lb to the stud, or 48 ft-lb to the nut that threads onto the stud. Both are involved in fastening the yoke to the body.

The only 34 ft-lb recommendation is for the bolts that actually go into the engine. That seemed crystal clear, and I've already followed that advice.

Back to the studs mentioned above. With the heads on them at 7 mm, the only wrench I have that's that small is about 4" long. If I'm supposed to crank that to 48 ft-lb, I need to get a longer wrench...I'm not sure I can put almost 150 lb of force on that little wrench, which is what I'd need to accomplish 48 ft-lb. In any case, it just seems to be asking for trouble--I think with that much torque you'd be likely to tear up the wimpy little 7 mm heads. I put 'em in basically pretty much as tight as I could with the little wrench I mentioned and am going from there. (When the nuts are threaded on and torqued to 48 ft-lb, that's gonna put a lot of outward force on the stud threads in the body, which should make the fit pretty secure---I just don't see them coming undone.)

[san rensho]

Its 48 for the studs that go into the frame. Then, its 34 for the NUTS that go onto the studs. Very straightforward.

I used a cheap 7mm socket on my torque wrench and I had absolutely no problem getting the torque to 48 on the studs.

[Frodo]

This has largely become a mental exercise for me---I've cranked on enough variously sized nuts & bolts (stripped a few!) to have a pretty good "feel" for what's about right, torque-wise. (With the total inaccessibility of so many of them on Boxster repairs, I've considered tossing the torque wrench into the trash can.) But, I'm sorta having fun with the discussion...here's the diagram:



Now, back to my list from Bentley:

A) Engine mount to engine 34 ft-lb
B) Engine yoke to body 48 ft-lb
C) Engine yoke to engine mount 48 fl-lb

Is it just me, or isn't it clear that "A" refers to Bolts 7 & 8 in the diagram? That's the only torque value in this section of Bentley that specifies 34 ft-lbs.

And "B", to me, seems just as clearly to refer to the fasteners numbered 1 (of which there are actually four total). Inconveniently, Bentley didn't specifically provide separate torque values for the stud and nuts in their description.

Likewise, "C" corresponds to nuts/bolts 2 & 3. Right?

Where do you guys get "34 ft-lb" for the torque setting for the nuts (numbered 1, in the diagram) to the studs??