UD Pulley instal

**Forgiven** · 04-10-2014, 06:59 PM

Who here has done this on a LS1 with automatic? I am wondering how to keep the crankshaft from turning. There is that opening near the flywheel, but it is round, not a good area to jamb a big screwdriver in. I understand the pulley bolt needs 250 ftlb of torque, that is a lot to break loose and tighten again. What did you use? Thanks.

**pajeff02** · 04-11-2014, 02:16 AM

Although I have not done it personally, it wouldn't surprise me if most guys simply took it off with an air impact and then put it back on the same way. I have a tool for holding the flywheel stationary, but no way it would work through the tiny access ports on the LS setup. They make strap wrenches, but I doubt they would bite hard enough on the pulley surface to hold it.

**Forgiven** · 04-11-2014, 06:56 AM

Yes Jeff I figured that as well, but I do not have air equipment. I may have to take it somewhere and have it done. Perhaps someone here has figured a way to do it with hand tools.

**pajeff02** · 04-11-2014, 11:40 AM

Hmm. I found this: http://www.ebay.com/itm/LS1-flywheel...-/121307438616

**98TransAmWs-6** · 04-12-2014, 10:27 PM

Yeah I used my impact with 600ish ft lbs of torque to remove the bolt and then used a 3 jaw gear puller to actually pull the pulley off the crank. You should never put the pulley back on using a impact to drive it in with the bolt. There is a special tool used for it that spreads the pressure out so you don't damage the threads, which you can use an impact on it if you want but you can use hand tools as well. You can buy the tool that Jeff posted and then use a really big breaker bar to break it loose. I have removed my pulley like 3 or so times lol and I bought the impact (electric version) for the purpose the first time and I have to say it was well worth it just for that.

**kingls1** · 04-13-2014, 04:44 PM

Originally Posted by pajeff02

Hmm. I found this: LS1 Flywheel Holding Tool | eBay

Neat idea, looks easy enough to fab up, guess I should cut some chunks of the old flywheel before I scrap it......guessing it bolts in where the starter goes?

**pajeff02** · 04-13-2014, 05:38 PM

That's what it looks like.

**Forgiven** · 05-14-2014, 07:49 PM

OK, I can not add any more photos here, so have to describe it....I got a small piece of channel iron 2" wide and carved it up until it would lock inside the auto bellhousing engaging the teeth on the flywheel. Got the bolt off using my floor jack against a breaker bar. 3 prong puller got the wheel off. I found a bolt about 1" longer than the stock bolt, put a big washer on it and started the UD pulley with that. Was able to finish pulling it in place with the stock bolt. That used bolt then needs to be torqued to 240 ftlbs. Done. (If you use an new bolt GM told me to torque it to 110 ftlbs, back it off, retorque to 59 ftlbs, then turn another 125 degrees....)

**0rion** · 05-14-2014, 09:15 PM

I can't tell from your post if you did but it's a really bad idea to reuse the stock bolt because it's been stretched and you'll lose clamping force. Stock style balancer bolt needs to be installed using a torque angle gauge. The stock specs are 37 ft/lbs and then 140 degrees after the balancer has been seated with the initial 240 ft/lbs. Like I say.....I can't tell from your post if you left your old bolt in there or just used it to seat the pulley. Hopefully though you used a new bolt. When I did mine I went with an ARP bolt.
As far as the flywheel I was able to hold it using a couple of long screwdrivers where the starter would mount.....I had the starter off.

**pajeff02** · 05-15-2014, 02:26 AM

^^ If I recall, ARP bolts are reusable and that is one of the advantages of upgrading to them. Does this apply to the ARP balancer bolt?

**0rion** · 05-15-2014, 03:28 AM

yep.....it's not a TTY bolt. I forget what I torqued that bolt down to.....I'm thinking 240. I just know it took all I had to get the wrench to click.

**Forgiven** · 05-15-2014, 08:35 PM

Thanks for the interest. I got my info. from a GM service desk and did decide to go with the used bolt at 240 ftlbs which is what they said to torque it to. Honestly it is a simple pulley on a crank that is turning some accessories....it is a tight fit to start with and it certainly is not going anywhere with that bolt on there. I am not concerned about it.

**0rion** · 05-15-2014, 10:25 PM

then the service desk you spoke with was wrong on the specs and if they recommended you using your old bolt then add reckless to that also. They should never recommend that. You can use it to seat the pulley but then you need to use a new bolt for the final torque sequence. Hopefully it'll start shredding belts before it comes off and kills someone. Chances are when it does come off it's going to trash your crank too. I think you're underestimating the forces that are on that pulley....hence the insane torque on the bolt to begin with. Congrats on saving $28 for the ARP bolt and good luck.

**pajeff02** · 05-16-2014, 02:18 AM

^^ I have to agree. The "torque to yield" style stock bolts stretch upon initial installation, and once they are removed you should throw them away. They can never stretch again and are compromised no matter how tight you torque them. On something as important as the crank damper you should at least install a new stock GM replacement bolt if you do not wish to upgrade to an ARP.

**Forgiven** · 05-16-2014, 08:15 AM

Well if I was given the wrong advice this is where I am at, as it is all together now. Can either of you give me more than one actual case where an old bolt was used and a harmonic balancer actually came off of a LS1 motor? When I see that it has actually happened to others I will do what you suggest.

***SMWS6TA*** · 05-16-2014, 09:30 AM

I remember 2-3 yrs ago we had someone on here that had the bolt snapped and threw his serpentine belt and pulley off. He even posted a pic about it....

It's not just a simple bolt( 240ftlbs is one hell of a lot of torque to be under). Most cases the bolt will crack under the stress and back out plus leaving the broken end in the crank. Now the crank pulley is no longer being held, it can start to walk. Once that happens if you're lucky you catch it in time however if at the track or under hard launch it can come off.

We aren't trying to flame you just telling you that reusing TTY bolts is wrong. You may get "lucky" and not have one incident, however the odds are not in your favor.

Why would you risk your engine & safety (as well as others "flying debris") over a $28 ARP bolt or $14 TTY GM replacement?

**98TransAmWs-6** · 05-16-2014, 09:41 AM

Originally Posted by Forgiven

Well if I was given the wrong advice this is where I am at, as it is all together now. Can either of you give me more than one actual case where an old bolt was used and a harmonic balancer actually came off of a LS1 motor? When I see that it has actually happened to others I will do what you suggest.

Do a Google search I have found at least 5 instances where this exact situation has happened. To me it is not worth the risk to save $28 vs buying a ARP crank bolt but to each their own I guess.

**pajeff02** · 05-16-2014, 12:10 PM

^^

Why take the risk? I can upload the language from the factory service manual regarding TTY bolts if you would like.

Here is a blurb from the ASE study guide on TTY bolts: Torque to Yield Bolts

**0rion** · 05-16-2014, 01:27 PM

I understand where you're at and it sucks. You were just given some really terrible advice. I don't think it's really a matter of "if" that pulley comes off but "when". Just trying to save you some real headache down the road. You think it sucks having to pull that bolt now.....wait until you see what's in front of you if that bolt jacks those threads up in the crank.

**Forgiven** · 05-17-2014, 06:16 AM

OK, I get it. I also appreciate your patience with me in this. It is better to be safe than sorry. This coming week I intend to get that bolt off and put a new one on to the specs I was given from GM. Initial 110 ftlbs, back it off, then 59 ftlb + 125 degrees more. Then I should be good to go. When I put the old bolt back in I am sure it stretched as I did it, but I certainly do not want it to fail due to being over stressed.