LTW Flywheel bolts backed out with video.

surebimmer · 01-10-2010, 08:01 PM

Well I had this vibration from the transmission. Noise was getting loud. So today i got around to pulling the transmisson to see what was going on in there. Here is the video of what I found.

http://home.comcast.net/~rj.dk.sanch...heel.e30m3.3GP

The flywheel bolts backed out. All could be taken out with my fingers. Bolts were all torqued to spec that came with the UUC LTW flywheel and had the locktite that was supplied with the flywheel. Flywheel was brand new and installed about 7 mouths ago. Driven about 4000 miles. No damage seems to be done. So there going to go back together with red locktite and torqued to BMW spec this time.

Anyone else heard of this happening. Some other problem i may need to check into?

matt · 01-10-2010, 08:40 PM

What's your rev limit?

We don't suggest spinning light flywheels past 7k on S52s.

surebimmer · 01-10-2010, 08:48 PM

It's AA software for sunbelt cams. So 6900 rpm.

matt · 01-10-2010, 08:58 PM

You sure about that? I thought that software allowed 7400 or so... I could be wrong.

Anyway, we see all sorts of issues like that (including probably 5 cases of the flywheel bolts backing out) when motors are spun past 7000 commonly with light flywheels. It seems to be a harmonic issue with the crank that only occurs commonly on the S52.

erik325i · 01-10-2010, 09:07 PM

Wow, that sucks Kyle. I've read plenty of not so great stories about the UUC flywheel in the bimmerforums track section. Hopefully the bolts will hold tight with the locktite.

Erik

FredK · 01-11-2010, 04:42 AM

Were the threads in the crank completely degreased prior to assembly?

gobuffs · 01-11-2010, 04:57 AM

Happened on my Euro motor with the Blue flywheel last year after having it in for 4 years without issues. Stupidly I had the tranny off and didn't check the flywheel bolts. Unfortunately it seems that retightening flywheel bolts with the blue flywheel is something that needs to be put on a regular schedule.

evil_twin · 01-11-2010, 05:48 AM

damn thats crazy! at least you found your problem though

sharky · 01-11-2010, 08:05 AM

Pretty common with the UUC flywheel for some reason, I have heard about this happening many many times. Call Rob at UUC, I am sure he can answer questions and give you a answer of what needs to be done to keep them from backing out.

BenM · 01-11-2010, 08:38 AM

I bought a UUC Stage II Flywheel (the blue 8.5lb. one) and E34 M5 clutch setup from a guy that had this happen as well. The setup had less than 500 miles on it and happened to him at the track (Watkins Glen). He ended up replacing it with a JBR/Clutchmasters setup which he has been extremely satisfied with. When I received it, there were divits and burrs around the holes, but I said fuck it and just deburred them as best I could.

When I installed the setup on my M50TU, I used those 2 small tubes of locktite UUC sent me on the crankshaft (literally poured it into the threaded holes). I also had a large stick of the non-liquied red locktite that I liberally coated each bolt in before installing. In addition to this I also overtorqued the flywheel bolts by about 10-15ft. lbs. just to make sure the bolts wouldn't become loose.

So far I haven't had any problems, but then again I haven't taken the car to any AutoX or Track days. Best of luck rectifying the situation.

5KWattson · 01-13-2010, 10:37 AM

this same thing happened on my m20 but it was only a lightened stock i flywheel but it was tq to spec...i never tried to fix it with locktight since i was swapping in my m50 but i did use the same flywheel on the m50 so far no problems with it coming loose

Dominic49 · 01-13-2010, 10:48 AM

Quote:

Originally Posted by BenM

I bought a UUC Stage II Flywheel (the blue 8.5lb. one) and E34 M5 clutch setup from a guy that had this happen as well. The setup had less than 500 miles on it and happened to him at the track (Watkins Glen). He ended up replacing it with a JBR/Clutchmasters setup which he has been extremely satisfied with. When I received it, there were divits and burrs around the holes, but I said fuck it and just deburred them as best I could.

When I installed the setup on my M50TU, I used those 2 small tubes of locktite UUC sent me on the crankshaft (literally poured it into the threaded holes). I also had a large stick of the non-liquied red locktite that I liberally coated each bolt in before installing. In addition to this I also overtorqued the flywheel bolts by about 10-15ft. lbs. just to make sure the bolts wouldn't become loose.

So far I haven't had any problems, but then again I haven't taken the car to any AutoX or Track days. Best of luck rectifying the situation.

too much locktite can cause it not to harden..... follow the directions on the package

01-10-2010, 08:01 PM	#1
surebimmer E30 Modder Join Date: Jan 2004 Location: Bay Area, CA Posts: 901	LTW Flywheel bolts backed out with video. Well I had this vibration from the transmission. Noise was getting loud. So today i got around to pulling the transmisson to see what was going on in there. Here is the video of what I found. http://home.comcast.net/~rj.dk.sanch...heel.e30m3.3GP The flywheel bolts backed out. All could be taken out with my fingers. Bolts were all torqued to spec that came with the UUC LTW flywheel and had the locktite that was supplied with the flywheel. Flywheel was brand new and installed about 7 mouths ago. Driven about 4000 miles. No damage seems to be done. So there going to go back together with red locktite and torqued to BMW spec this time. Anyone else heard of this happening. Some other problem i may need to check into? __________________

01-10-2010, 08:40 PM	#2
matt No R3VLimiter Join Date: Oct 2003 Location: Atlanta Posts: 3,724	What's your rev limit? We don't suggest spinning light flywheels past 7k on S52s. __________________ The Racer's Market - BMW M50 Tuning and Turbos Email me for free shipping on TRM chips! - matt at racersmarket dot net

01-10-2010, 08:48 PM	#3
surebimmer E30 Modder Join Date: Jan 2004 Location: Bay Area, CA Posts: 901	It's AA software for sunbelt cams. So 6900 rpm. __________________

01-10-2010, 08:58 PM	#4
matt No R3VLimiter Join Date: Oct 2003 Location: Atlanta Posts: 3,724	You sure about that? I thought that software allowed 7400 or so... I could be wrong. Anyway, we see all sorts of issues like that (including probably 5 cases of the flywheel bolts backing out) when motors are spun past 7000 commonly with light flywheels. It seems to be a harmonic issue with the crank that only occurs commonly on the S52. __________________ The Racer's Market - BMW M50 Tuning and Turbos Email me for free shipping on TRM chips! - matt at racersmarket dot net

01-10-2010, 09:07 PM	#5
erik325i No R3VLimiter Join Date: Jan 2005 Location: Nor*Cal San Jose Posts: 3,557 Images: 5	Wow, that sucks Kyle. I've read plenty of not so great stories about the UUC flywheel in the bimmerforums track section. Hopefully the bolts will hold tight with the locktite. Erik __________________

01-11-2010, 04:57 AM	#7
gobuffs E30 Addict Join Date: Dec 2004 Location: Earth Posts: 452	Happened on my Euro motor with the Blue flywheel last year after having it in for 4 years without issues. Stupidly I had the tranny off and didn't check the flywheel bolts. Unfortunately it seems that retightening flywheel bolts with the blue flywheel is something that needs to be put on a regular schedule.

01-11-2010, 05:48 AM	#8
evil_twin R3VLimited Join Date: Nov 2007 Location: Centreville / Chantilly, Virginia Posts: 2,781	damn thats crazy! at least you found your problem though __________________ I got a fender roller now! LMK if you need me to roll your fenders or want to rent the tool from me locally. Paypal: vdang5@gmail.com My Feedback Thread

01-11-2010, 08:05 AM	#9
sharky R3VLimited Join Date: Jan 2005 Posts: 2,390	Pretty common with the UUC flywheel for some reason, I have heard about this happening many many times. Call Rob at UUC, I am sure he can answer questions and give you a answer of what needs to be done to keep them from backing out.

01-13-2010, 10:37 AM	#11
5KWattson E30 Modder Join Date: Apr 2009 Location: Fresno Cali 559 Posts: 809	this same thing happened on my m20 but it was only a lightened stock i flywheel but it was tq to spec...i never tried to fix it with locktight since i was swapping in my m50 but i did use the same flywheel on the m50 so far no problems with it coming loose __________________ "God created turbo lag to give V8's a chance" Taylor D.