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Old 08-13-2011, 06:55 PM   #1
JohnSellers
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I found one thread HERE about subject, but it's not a definitive reference - there might also be difference in models/engines. (I'm sure there are other threads about this too, but I'm not as guilty as some about posting without searching....)

I'm in the middle of timing belt job - with lots of other maintenance (plugs, belts, coolant, hoses, valve cover gaskets, etc.) - and broke the crank pulley bolt loose. This bolt measures about 12mm dia, and thread pitch is about 16tpi. (is this fine thread or coarse?)

I don't yet know what recommended/allowable torque for this fastener size is, but 130 ft-lbs (FSM spec) seems awfully high. The bolt appears like it might be hardened, sort of like a Grade 5 or Grade 8 fastener. But, the threads are a bit rough, looking almost like they've been stressed close to the failure point. Doesn't appear like there's much "meat" to the threads either. (not much thread "depth"...) I'm just a bit hesitant to put this much torque on this bolt when I install the pulley again without some more reassurance.

I've seen 95 ft-lbs quoted for the crank bolt in other sources - is this a spec for other model years? What's the difference? Bolt size? Thread pitch?

BTW - I have a new GrimmSpeed pulley to put back in place of OEM. Don't know if this will make a difference or not - will a lightweight pulley be more secure with different torque than FSM spec? Or, makes no matter - needs to be the same regardless? Which would fail first, bolt thread or crank thread?

I know - lots of questions. But, ruining this engine now would ruin my day/month/year...

Any hints appreciated.

Thanks,
John
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Old 08-13-2011, 07:36 PM   #2
02RSBRP
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On GrimmSpeed website in the instruction video it says to torque that bolt to 94 ft-lbs.

Several of the other Lighted pulley manufactures say 95 ft-lbs

The FSM under SOHC section for 02 says: Tightening torque: 177 Nm (18 kgf-m, 130.2 ft-lb)

The FSM under DOHC section for 02 says: Tightening torque: 127 N-m (13 kgf-m, 94.0 ft-lb)

This is where the confusion is coming from. It's been a long argument over many many threads.

All the new 2.5l engines call for 130 ft-lbs. So it appears that for the 2.0l, it's 94 ft-lbs and the 2.5l its 130 ft-lbs.
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Old 08-13-2011, 09:15 PM   #3
Buzzmanrm
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120-130 sounds right I usually just tap it with my 3/8" impact and snug it down, I've checked it and I usually get about 100-130 LBS with it. Never in the hundreds of crank pulleys I've done has ever come off.
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Old 08-13-2011, 10:15 PM   #4
perds
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Subaru says whaaa

not trust the manual?
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Old 08-13-2011, 10:52 PM   #5
V8Slayer
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I always torque the crank pulley bolt down to 100 ft-lb. Its what the techs at my dealership recommended years ago when it was first installed and that is what i torque it down to when i remove/reinstall, no issues to date.
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Old 08-13-2011, 11:27 PM   #6
02RSBRP
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Quote:
Originally Posted by V8Slayer View Post
I always torque the crank pulley bolt down to 100 ft-lb. Its what the techs at my dealership recommended years ago when it was first installed and that is what i torque it down to when i remove/reinstall, no issues to date.
Do you have a 2.0l or a 2.5l? There is where the difference is.
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Old 08-13-2011, 11:30 PM   #7
V8Slayer
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I have a 2.5L, just like you.
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Old 08-14-2011, 08:02 AM   #8
JohnSellers
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Thanks for the time, guys.

All the references I found show recommended torque at about 95 ft-lb; that's for a Class 12.9 metric bolt, with DRY threads. (converted from N-M) Torque on a lubed fastener should be about 20% less. And, of course, lubing the bolt before installation is also suppposed to be the norm.

This Subaru crank bolt must be much stronger than any fastener class I see listed in bolt specs, if it survives 130 ft-lb. I can't find any specs that show recommended torque that high for a 12mm bolt.

I wouldn't worry if the threads didn't appear to be stressed, but they look like they're right on the edge of failure. They don't look pristine, like a new bolt.
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Old 08-14-2011, 12:38 PM   #9
02RSBRP
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I've torqued ever single on of mine to 130 ft-lbs per the service manual.

That bolt has to be bigger than 12mm, the head on it is 22mm and I don't remember the bolt part being half that size. If you look at a torque spec table, if it's even a 14mm that puts it in the torque range of 130 ft-lbs.

I can't seem to find it any more, but subaru did change the torque spec on this bolts at one point to the 130 ft-lb value due to some pulleys coming loose at 95 ft-lbs and destroying the keyway on the crank.
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Old 08-14-2011, 02:36 PM   #10
JohnSellers
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It's a 12mm bolt - although thread pitch measures between what is std for metric. Standards list 1.5mm and 1.75mm - this bolt looks to be about 1.6mm thread pitch. It must be some heavy-duti-special that Subaru made just for this application.

You're correct about the head - it needs a 22mm socket. But, I measured it many times - it's no bigger than 12mm diameter. (may be slightly less, in fact...)

I torqued it to 100 ft-lbs, and it felt pretty good - so I went ahead and tightened to 120 ft-lbs. Gonna leave it there....

Thanks for all the help.
John
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Old 08-14-2011, 05:24 PM   #11
williaty
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Note that you're also supposed to dip it in motor oil before installing it. For the 2002 RS, factory instructions are:

1) Clean the threads of the bolt and the threads in the crank
2) Apply engine oil to the crankshaft pulley bolt seat and threads
3) Temporarily tighten to 33lbf-ft
4) Tighten to 130.2lbf-ft
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