DRCE

Messing with a friends LS2 out of his Trailblazer SS. Got the timing cover off and noticed that there is one large bolt holding the cam sprocket on instead of three bolts like I've seen in other LSx applications.

Well I put a socket on it and reefed on it pretty good, but it just won't break loose. I tried both directions in the event that it was a reverse thread for some queer reason. So I have two questions.

1) When did the LSx switch over to this type of cam sprocket bolt?
2) Has anyone had issues removing said bolt, I'm inclined to try the impact on it.
3) I assume its torque to yield, does anyone know the part number or torque value of the bolt??

Thanks very much for any help.

DRCE

50 views and no input???? Come on somebody has to know? I'm more interested in where to get another and what the spec is. I'll get it off.

TheLS1Kid

iTrader: (12)

What year is it?

I'm looking on my GM service website under a 2006 Trailblazer with a 6.0 and its showing the cam sprocket being held on my 3 bolts.

TheLS1Kid

iTrader: (12)

The 2008 is even showing 3 bolts.

Tom@SpeedInc

iTrader: (5)

http://www.ls1speed.com/cont.cfm?cid=C0000752

DRCE

Ok I've gotten to the bottom of this. Apparently in 2007 they went to a single bolt to hold on the cam sprocket. 2008's are said to be back to three bolts, but I haven't seen one to verify this info.

Thanks for the input here fellas.

DRCE

Just curious, how could you damage the chain by removing a bolt?? Are you saying by putting tension on the chain when trying to break the bolt free?? I'm liking the impact approach more and more.

DRCE

I see your point. I have an adapter I made that fits on the back of the crank and stops the engine from turning on the stand. That offers a much more stable resistence to loosen things against.

Even still I see what you mean about tension, however don't you feel that the increased diameter of the bolt is stout enough to absorb the load of torquing it on and removing it? My guess is that is why GM made the bolt the way they did, make it as large as the three bolts combined and lengten it to disperse the load put on it during the installation and removal process. Not to mention during operation.

In the end, I opted out of the impact and just used an 18" breaker bar and socket. It came off on the first attempt without incident.

TheLS1Kid

iTrader: (12)

You are correct. 2007 is the only year with the single bolt. Check it out.
http://service.gm.com/servlets/BlobS...psdsubkey=6313

eallanboggs

iTrader: (1)

Isn't the single bolt system found on engines with VVT?

Spinmonster

I guess there are no adjustable timing chains available for the newer LS2's or LS3's.

eallanboggs

iTrader: (1)

LS1Speed appears to have the cure for this single bolt delema with their custom sprocket. You just buy the old style cam(3 bolt) you want with the duration, lift, LSA, advance, etc., you want and install it with their custom sprocket on you one bolt VVT engine. If you look at the photo on their site you can see it has the single center bolt holes as well as the legacy 3 bolt holes with the dowel hole meaning their sprocket should work with either system.

DRCE

If I'm not mistaken, the PCM/ECU can not account for cam timing changed at the timing set. Rather it can only change spark timing that the engine will see. Two different types of timing, and not to mention 90% of the adjustable sets out there are set at zero advance anyhow.

SS Enforcer

I think you will find thats the stock Ls7 sprocket, I have bought a few before to suit the new 2007 models. The single bolt hole will be too small for the cam bolt . It also wont fit the 2007 camshaft due to cam being a bit smaller in diameter than a ls1 cam. It's too late here for me to go checking in my garage but I think I got it right. It will work fine for any ls series aftermarket camshaft for the newer motors with the 58 relucter crank.

cheers

LSInnovations

iTrader: (7)

I just did this swap on a 07 Vortec Max 6.0L truck with a single bolt and DOD/VVT.

I swapped out the lifters to LS7 lifters and used a LS7 upper timing sprocket. Worked great.

BLACKND

iTrader: (5)

I am wondering about my new Truck. I just bought an new Comp Cams(LS1 Design) 206/212 112 LSA. My truck is a 2007 Silverado 4.8 (LY2 engine Code). I know the 4.8 is a gen 4 design, but the 4.8 liter is the only engine in the lineup without VVT and/or AFM. My truck also came with the 243 heads. I am wondering if my truck will have the 3 bolt sprocket or the single bolt, and what valvesprings come stock in the 243 heads, With the lowlift cam I'm going to use, I wanna use LS6 springs.

eallanboggs

iTrader: (1)

If you don't have VVT(cam phaser) you're not going to have that type of cam. You should be able to bolt the new cam right up. As for you springs you didn't mention the lift numbers. You need to find out the lift numbers for the OEM springs and compare that to the lift of the new cam to see if you're over the limit or close to it. If you're close you should do the swap. Buy the Vinci/Crane tool if you do.

1BADAIR

iTrader: (1)

if you change the cam in a 2007 TB ss you have to switch to the 2005 gear. No one has single bolt cams yet

HeapaShifter

iTrader: (2)

I ran into this problem about a month on a 07 silverado with the 6.0L. I didn't know what to think at first. Found out only the engines with vvt have it. I got a kit from lingenfelter that had the 3-bolt sprocket, 3 bolts, and a different chain tensioner. I had to get a new front cover without the vvt phaser hole in it too. Then I was set to run any aftermarket cam.

HSV-GTS-300

https://ls1tech.com/forums/generation-iv-internal-engine/806946-cam-cover-clearance-issues-2007-ls2.html#post8141999