[Z06] valve springs
Thread Starter
Instructor
Joined: Feb 2004
Posts: 205
Likes: 0
From: tn
valve springs
I bought a 2002 zo6 about 6 months ago and i love it. Have not had any problems until last friday i was comming home from b.g. and i broke a valve spring . What do you think would cause this .Had dealer install a new one . Someone told this is a problem with 02's.I was wondering if other people are having the same problem and how common it is.
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Safety Car
Joined: Jul 2004
Posts: 3,904
Likes: 29
From: Vancouver Washington
I bought a 2002 zo6 about 6 months ago and i love it. Have not had any problems until last friday i was comming home from b.g. and i broke a valve spring . What do you think would cause this .Had dealer install a new one . Someone told this is a problem with 02's.I was wondering if other people are having the same problem and how common it is.
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Pro
Joined: Oct 2007
Posts: 632
Likes: 2
From: Columbus Ohio
This is a fairly common problem on 02-03 z06's... apparently with the more aggressive camshaft in 02, as compared to 01, the springs were not up to duty. It seems to occur about every other month to corvette forum members. 04 cars seem to be more immune as I have only heard of one or two I believe that have had them fail.
I as well as numerous others have changed them out for good measure and I at least put a set of fresh LS2 springs (same springs the factory went to in 04) in my bone stock 03 as soon as I got it (GM PN 12499224) First "mod" after the Column Lock Bypass.
Glad to hear you didn't suffer any more damage.
Here are a few more threads on the matter:
http://forums.corvetteforum.com/c5-z...-a-spring.html
http://forums.corvetteforum.com/c5-z...e-springs.html
I as well as numerous others have changed them out for good measure and I at least put a set of fresh LS2 springs (same springs the factory went to in 04) in my bone stock 03 as soon as I got it (GM PN 12499224) First "mod" after the Column Lock Bypass.
Glad to hear you didn't suffer any more damage.
Here are a few more threads on the matter:
http://forums.corvetteforum.com/c5-z...-a-spring.html
http://forums.corvetteforum.com/c5-z...e-springs.html
Last edited by hpfiend; Feb 3, 2009 at 01:20 PM.
Pro
Joined: Jun 2003
Posts: 624
Likes: 7
From: St. George, UT
Do you put the PAC 1218s springs in a bone stock or is it just for the larger cam also? Where do you get the PAC's?
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Safety Car
Joined: Jul 2004
Posts: 3,904
Likes: 29
From: Vancouver Washington
You can put either spring on a bone stock engine. The 1218s allow for .600 lift (more than enough for a stock cam) and the 1518's, which are more expensive, allow for a .650 lift (in case you add a cam or 1.8 rockers later). Several Forum vendors carry PAC. I got mine from Herron Performance.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
Any recommendation for the best spring tool to use for this operation?
Pro
Joined: Oct 2007
Posts: 632
Likes: 2
From: Columbus Ohio
^^^^ My '03 only had 12K on it when I did it...
On the two rear cylinders on each bank you need to use a quality screw type spring compressor- all of the others can be done easily with a lever type compressor. You will also need a compression tester fitting or at least an air fitting with the same threads as a spark plug hole and an air compressor to hold the valves so you do not have to pull the head. A powerful air compressor will put the engine at top dead center so make sure it is in neutral before give it air.
On the two rear cylinders on each bank you need to use a quality screw type spring compressor- all of the others can be done easily with a lever type compressor. You will also need a compression tester fitting or at least an air fitting with the same threads as a spark plug hole and an air compressor to hold the valves so you do not have to pull the head. A powerful air compressor will put the engine at top dead center so make sure it is in neutral before give it air.
Last edited by hpfiend; Feb 4, 2009 at 06:57 AM.
Pro
Joined: Oct 2007
Posts: 632
Likes: 2
From: Columbus Ohio
They could have raised the rev limit with the tune and really gave the springs a workout. But- this has happened on numerous engines that were bone stock and never over-revved- lots of guys/gals report it has happened at idle or cruising on the freeway.
Pro
Joined: Jun 2003
Posts: 624
Likes: 7
From: St. George, UT
Yep..... mine went out just driving around town. Had no idea what had happened. Real pita trying to figure it out. Dealer was aware of the problem and knew right what to do. (collect my money) 
Now that I take it to the road coarse track I want to do all the springs.
Now that I take it to the road coarse track I want to do all the springs.
Safety Car
Joined: Jul 2004
Posts: 3,904
Likes: 29
From: Vancouver Washington
The Crane valve spring tool is the one you want. Vinci High Performance VHP has them as well as the air line adapter for the spark plug hole.
Pro
Joined: Oct 2007
Posts: 632
Likes: 2
From: Columbus Ohio
Nice company! however, on a side note I am not sure their Micronite(sp) treatment of the ring gear was a fair test- if they used a 7.5" 10 bolt coupled with a MANUAL transmission, a 200 shot of nitrous, AND documented 4-5K rpm clutch dumps on STICKY tires I would be more convinced- I don't think it would be so shiny after 40 runs ;-)
Last edited by hpfiend; Feb 5, 2009 at 08:15 AM.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
^^^^ My '03 only had 12K on it when I did it...
On the two rear cylinders on each bank you need to use a quality screw type spring compressor- all of the others can be done easily with a lever type compressor. You will also need a compression tester fitting or at least an air fitting with the same threads as a spark plug hole and an air compressor to hold the valves so you do not have to pull the head. A powerful air compressor will put the engine at top dead center so make sure it is in neutral before give it air.
On the two rear cylinders on each bank you need to use a quality screw type spring compressor- all of the others can be done easily with a lever type compressor. You will also need a compression tester fitting or at least an air fitting with the same threads as a spark plug hole and an air compressor to hold the valves so you do not have to pull the head. A powerful air compressor will put the engine at top dead center so make sure it is in neutral before give it air.
Others on the board have mentioned another way to keep the valves in place is to stuff some clean nylon rope inside the cylinder when it's at TDC and valves closed. Seems like an easier, and maybe safer way to go. Would hate to see the air pressure suddenly go to zero and hear the valves drop to the bottom of the cylinder.
