Crank pulley coming loose on GT3's.....
10-07-2013, 04:05 PM
#32
8th Gear
Join Date: Jan 2012
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Hi, this happened to me yesterday on 996 turbo. I had a dead battery before, so I believe this must have triggered it (more load on the crank pulley). So the pulley came off while I was driving (luckily I was not going fast at that moment, but I was before).
With the help of my nephew we were able to fix this on the spot: the only thing that actually suffered was the center bolt: some of the grooves were damaged so we had to use a small file to fix them: otherwise the bolt would not go into the crankshaft all the way. You also have to remove the leftmost pulley to have access to the crankshaft. Not a very easy thing to do, but doable.
From this topic I learned that some people had to replace the crankshaft because of this failure -- ouch!!
I have found no trace of any locking pin, however. Is it supposed to be there? It's not mentioned in the parts catalog either. Does any one have any idea, please?
Bolt p/no is 99921712801.
With the help of my nephew we were able to fix this on the spot: the only thing that actually suffered was the center bolt: some of the grooves were damaged so we had to use a small file to fix them: otherwise the bolt would not go into the crankshaft all the way. You also have to remove the leftmost pulley to have access to the crankshaft. Not a very easy thing to do, but doable.
From this topic I learned that some people had to replace the crankshaft because of this failure -- ouch!!
I have found no trace of any locking pin, however. Is it supposed to be there? It's not mentioned in the parts catalog either. Does any one have any idea, please?
Bolt p/no is 99921712801.
10-07-2013, 07:13 PM
#34
Rennlist Member
I have to replace my RMS this month before VIR, so will probably just replace this crank pulley bolt/washer and thread-lock it with 272. Also going to check my cam-actuator bolts while the motor is out, and re-torque if necessary.
10-08-2013, 02:25 AM
#35
Mvez,
Hold on a day or two, we're putting the final touches on the solution for all of this bolt loosening, cam adjuster, oil pump destroying shenanigans...
Will be updating this week...
Hold on a day or two, we're putting the final touches on the solution for all of this bolt loosening, cam adjuster, oil pump destroying shenanigans...
Will be updating this week...
10-08-2013, 10:38 AM
#36
Race Car
just a very small dab of 272 on the crank bolt. That way you can still remove it with brute force if you have to do front main seal at any point. It's near impossible to get heat on the crank stub if that bolt ever has to come back out.
10-08-2013, 08:01 PM
#37
Former Vendor
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The stock pulley only has about 0.16" engagement. At 125ft/lbs it shouldn't be coming out. Reason it's coming out is the stock damper isn't working.
Our solution has 0.500 in of engagement and the damper actually works!
Our solution has 0.500 in of engagement and the damper actually works!
Last edited by RKAutowerks; 10-08-2013 at 08:22 PM.
10-08-2013, 09:07 PM
#41
Rennlist Member
It's always weirded me out that the GT3 RS has no harmonic damper and uses a single mass flywheel.
I do have a question though, would using polyurethane tranny mounst have any measurable effect on the resonance (increase)?
Last edited by Mvez; 10-08-2013 at 09:28 PM.
10-08-2013, 09:45 PM
#42
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uh, post more please. PM sent. I dealt with all this same crap with my E46 M3 back when SMF were being used, and the stock harmonic balancers were getting nuked by a massive resonance in the 4-5k range upon deceleration, until VAC started selling a custom built ATI unit for the S54.
It's always weirded me out that the GT3 RS has no harmonic damper and uses a single mass flywheel.
I do have a question though, would using polyurethane tranny mounst have any measurable effect on the resonance (increase)?
It's always weirded me out that the GT3 RS has no harmonic damper and uses a single mass flywheel.
I do have a question though, would using polyurethane tranny mounst have any measurable effect on the resonance (increase)?
Take a look through this if you haven't.
https://rennlist.com/forums/10816248-post1.html
if you want more in depth, I've got a reference paper that is very helpful on understanding engine harmonics and harmonic dampers...
Let me know and I'll post it in a different post (it to is super long...)
10-11-2013, 07:16 AM
#43
Engine and gear box mounts make no difference to the harmonics and what damage they cause (just) to the engine and gear box. LWFW make the gearbox vulnerable along with increased chance of engine issues.
I am guessing the inlet manifold issues on 4.0's are for the same reasons...
I am guessing the inlet manifold issues on 4.0's are for the same reasons...
10-11-2013, 01:15 PM
#44
On another post someone has had their Exhaust come apart. Same cause I'm told.
I was told this has happened alot on the Cup engines. The early exhausts in particular came apart.
This is the problem with this sort of failure. It's hard to undersatnd as there are no signs before failure happens. We all know Oil leaks, a noise that shouldn't happen, temperatures high etc.
I was told this has happened alot on the Cup engines. The early exhausts in particular came apart.
This is the problem with this sort of failure. It's hard to undersatnd as there are no signs before failure happens. We all know Oil leaks, a noise that shouldn't happen, temperatures high etc.
10-11-2013, 03:12 PM
#45
Rennlist Member
Engine and gear box mounts make no difference to the harmonics and what damage they cause (just) to the engine and gear box. LWFW make the gearbox vulnerable along with increased chance of engine issues.
I am guessing the inlet manifold issues on 4.0's are for the same reasons...
I am guessing the inlet manifold issues on 4.0's are for the same reasons...
