That s my luck! 
Do i need my crankshaft "pinned"?
Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,316
Likes: 2
From: St. Louis Mo
Do i need my crankshaft "pinned"?
I have a 427 that made 539 na rwhp and i swear that my balancer is rubbing on my steering set-up! It has 300 miles on it. and it looks like there is a little "screw sized protrusion" sticking out, making it difficult to get the belt off or on. Anyone know anything about something like that happening?
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
The balancer only needs to be pinned if you're running a supercharger. The resistince encountered turning the blower can make the crank pulley rotate backwards and the bolt will loosen and the balancer will walk off. If it's rubbing the steering then the balance is loose and walking off.
While you don't need it pinned, if you or you tuner didn't follow GM's bolt installation instructions w/ a new bolt then they usually back out. The crank pulley stays on the crank snout via an interefernce fit and relys on bolt stretch to hold it on.
That said, when I put my cam in I keyed the balancer because I wanted to be able to forget about it.
Post some pictures if you can.
While you don't need it pinned, if you or you tuner didn't follow GM's bolt installation instructions w/ a new bolt then they usually back out. The crank pulley stays on the crank snout via an interefernce fit and relys on bolt stretch to hold it on.
That said, when I put my cam in I keyed the balancer because I wanted to be able to forget about it.
Post some pictures if you can.
Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,316
Likes: 2
From: St. Louis Mo
Should i get a new bolt? What kind(aftermarket)? Thanks!!
Last edited by intoc6s; Sep 26, 2008 at 08:28 PM.
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
No... you'll have to re-do it all. take it back to them and make them do it right. You have to remove th esteering rack to get to the bolt. Here's the proper procedure as listed on www.ls1howto.com.
Seat your pulley back onto the snout of the crankshaft as best you can by hand. If you purchased a longer crank bolt, start threading this in now and pull the pulley on about a 1/4 or 1/2 an inch and remove the longer bolt. Use your old stock crank pulley bolt to pull the pulley onto the crankshaft until the bolt seems to get impossible to turn. Grab your biggest torque wrench and attempt to torque that bolt down to 240lbft. I have always stopped at 200lbft on my installs and I've never had a problem, so if you can't hit 240 (which I never have), don't worry about it. Now, break the bolt free and remove it.
Take your NEW crank pulley bolt and thread it in all the way by hand. Torque this bolt to 37lbft. Now, we need to stretch the bolt into place. Get your breaker bar and pipe extension, and try to turn the bolt 140degrees past where it is at now, keeping in mind the engine will be trying to turn some and those are degrees you can't count. Again, I always seem to get about 90-100 degrees worth (estimating, knowing what 90 degrees looks like) and leave it as is so don't worry about going crazy here.
Take your NEW crank pulley bolt and thread it in all the way by hand. Torque this bolt to 37lbft. Now, we need to stretch the bolt into place. Get your breaker bar and pipe extension, and try to turn the bolt 140degrees past where it is at now, keeping in mind the engine will be trying to turn some and those are degrees you can't count. Again, I always seem to get about 90-100 degrees worth (estimating, knowing what 90 degrees looks like) and leave it as is so don't worry about going crazy here.
Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,316
Likes: 2
From: St. Louis Mo
Is this a weekend project or is it pretty quick? We have a lift and air tools etc,. 
Thanks again!! Youre awesome!!
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
If you have a lift and know how to turn a wrench you may be able to have it done in a day.... getting the steering rack out of the way is the hardest part. From what I've heard you don't need to take the rack all the way out, there are ways to just get it out of the way. That website I linked will show you everything you need to know. Just look at the initial steps of the C5 heads/cam swap.
Get a brand new GM blancer bolt and start fresh. Many use extra red loc-tite for a little extra insurance.
Get a brand new GM blancer bolt and start fresh. Many use extra red loc-tite for a little extra insurance.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Couple of suggestions. The first is to replace the harmonic damper. It is likely loosening because it is the original and having been removed may have been damaged. Second, the tightening specification in the manual should be followed. Even though LS1howto mentions the correct bolt stretch, he uses a shortcut that could lead to further issues down the road. Do it once and do it correctly.
Next question, who's crank is in the 427, Eagle? There were issues with some Eagle cranks. You really should measure the crank hub snout diameter and the harmonic damper hub inside diameter to ensure there is enough interference in the fit.
Next question, who's crank is in the 427, Eagle? There were issues with some Eagle cranks. You really should measure the crank hub snout diameter and the harmonic damper hub inside diameter to ensure there is enough interference in the fit.
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Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,316
Likes: 2
From: St. Louis Mo
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
If you have the ASP installation instructions, they should tell you the interference fit requirements. Just measure the crank and the pulley and ensure fit is correct. You will need tools that measure to 1/10,000 inches to do this correctly.
Le Mans Master
Joined: Sep 2003
Posts: 6,276
Likes: 227
From: Farmington CT
Cruise-In VII Veteran
let's clear this up,
you have a shop that installed a 427? those aren't cheap; they didn't replace the bolt? I think the hack shop needs to fix the problem or foot the bill at shop that is in the know
you have a shop that installed a 427? those aren't cheap; they didn't replace the bolt? I think the hack shop needs to fix the problem or foot the bill at shop that is in the know
Melting Slicks
Joined: Dec 2003
Posts: 3,315
Likes: 17
From: Near Jacksonville Fl.
The balancer only needs to be pinned if you're running a supercharger. The resistince encountered turning the blower can make the crank pulley rotate backwards and the bolt will loosen and the balancer will walk off. If it's rubbing the steering then the balance is loose and walking off.
While you don't need it pinned, if you or you tuner didn't follow GM's bolt installation instructions w/ a new bolt then they usually back out. The crank pulley stays on the crank snout via an interefernce fit and relys on bolt stretch to hold it on.
That said, when I put my cam in I keyed the balancer because I wanted to be able to forget about it.
Post some pictures if you can.
While you don't need it pinned, if you or you tuner didn't follow GM's bolt installation instructions w/ a new bolt then they usually back out. The crank pulley stays on the crank snout via an interefernce fit and relys on bolt stretch to hold it on.
That said, when I put my cam in I keyed the balancer because I wanted to be able to forget about it.
Post some pictures if you can.
I would pin the balancer and use an ARP bolt to retain it.
Cheap insurance @ ~$30.00 for the bolt and you don't need to streach the bolt.
Just install the balancer till it bottoms out on the crank and install the bolt and torque to 150lbft.
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
^ Some of the '05 LS2s in the first C6s had issues and GM redesigned the bolt and had a TSB out for it.
For the C5s it's excedingly rare for an oem bolt/balancer installed properly to come loose. In this case the guys shop failed to follow proper procedure and re-used an old bolt which you cannnot do.
I went ahead and pinned my ATI super damper because it came with a keyway and I wanted the extra insurance.
For the C5s it's excedingly rare for an oem bolt/balancer installed properly to come loose. In this case the guys shop failed to follow proper procedure and re-used an old bolt which you cannnot do.
I went ahead and pinned my ATI super damper because it came with a keyway and I wanted the extra insurance.
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
I pinned mine using the ATI kit... drilling through my forged eagle crank was a royal pita, but I think it was worth it, if only for peace of mind. And like everyone else said... Just get an ARP bolt. I really hope for your sake that they didn't break the old bolt off in the snout, that can happen when you reuse the factory bolt to pull the balancer on.
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
I pinned mine using the ATI kit... drilling through my forged eagle crank was a royal pita, but I think it was worth it, if only for peace of mind. And like everyone else said... Just get an ARP bolt. I really hope for your sake that they didn't break the old bolt off in the snout, that can happen when you reuse the factory bolt to pull the balancer on.
Le Mans Master
Joined: Jul 2002
Posts: 7,370
Likes: 8
From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,316
Likes: 2
From: St. Louis Mo
I m so glad that it didn t blow this motor up! Cause your right- It wasn t cheap, and its new. I haven t even had a chance to see how good it mph s at the track yet!(only about 300 miles on it). I hate when problems arise but i always learn more about my Corvette when they do. I appreciate everyones comments and------Im gonna pin my crankshaft to assure that this doesn t come up again! I just need to find out where I get this "kit". Does the arp bolt have the pin and drillbit, etc, with it? Hmmm.... Thanks guys!- Jason