I totally agree on running PAC. If someone here is tracking your car as much as you have, they'd be wise to run anything but GM springs, stock cam or not. Stock springs arent made for extended high rpm use. I guess they could either pay several hundred dollars now for springs that ARE made for high rpm, or drop $5,000 or $10,000 on a new engine down the road. Their choice.....

 

GM 12499224 LS6 Valve Springs

 

Pac has a newer option of the 1218s, I think they call them 1218X. Supposed to have even greater endurance. IIRC they certainly have a greater price.

Heard of these?

 

Yup I have. I might go that route this time. Last time it was a cost vs benefit decision as I knew I would be replacing them in a couple years. Chances are the regular 1218's are fine but I would rather change them before there is an issue. In all honesty, like grinder said $300 springs every couple years is better than a $10k engine bill

 

No, I haven't. Not surprising, because I'm not keeping up with the latest valve spring development. My PAC duals have been in for 10 years, 52,000 miles. I have the same, new, PAC duals on the garage work bench. Changing them when it warms up in May!!

 

I went back and looked at the 1218x springs. They are marked as PACs RPM series now. Im not sure that was before. Maybe it was and I dont remember, haha. Considering I run up to 7400rpm on mine they are probably the better choice. Also, they are not that much more expensive than the regular 1218. When I bought my 1218's they were like $120 for a set. Now the 1218 is within $75 of the 1218x. Almost a no brainer!

 

2002 C5 Z06: I replaced my original yellow springs in 2009 at 25,000 miles This was mid way thru my 5th season of doing autocross & high speed timed events. Springs were replaced because I was getting nervous about reported valve spring failures on 2002 & 2003 cars. I looked at aftermarket springs, but went with GM yellow springs. The yellow springs were made in Germany, have a variable rate (beehive) design using elliptical wire that has been shot peened. That's just what you can see visually so its a pretty sophisticated design.

I continued to run track time events until 2017 with the replacement yellow springs. They are still in the engine, but the car is now only a daily driver.

As far as spring replacement goes, I jacked the rear off the ground with the car in 6th gear, plugs out and rotated the engine with the rear tire. The rocker arm position was used to find TDC and a bendy plastic straw to verify piston at top of stroke. I used small air compressor at about 90 - 100 Psi & Crane Cam tool which compresses both springs on one cylinder. 50 Psi is probably enough and with the piston at the top of stoke the valve can't drop more than a fraction of an inch anyway. The job probably took me 2 - 3 hours. The engine made a lot of noise when restarted after changing springs due to oil draining out of the lifters. Just let it idler for a few minutes and it will quiet down.

 

Presumably you'll be taking a deep dive this weekend. Let us know how the inspection went. How does that #8 valve and pushrod look?

 

Not good. Pushrod has a small bend to it but it is bent. So that will need replacing. That will be easy as its just a ls 7.40 pushrod. Bent pushrod on the top. Rolls somewhat ok but its trash.



I did an inspection and did not see any touching. However when turning the engine over to get to TDC the exhaust valve came up and I saw the intake valve also move up. I got the engine to TDC on #8 and decided to see how much the valve moves. Its way more than I thought. Pretty sure I can close the valve then make it touch the piston. I am not sure but I think the spring broke in two spots.


So now pricing stuff out. Going to go ahead and pull the head. A few buddies say put it together and do a leak down but I would rather take the valve all the way out and do a good inspection.

 

This is the latest number. Might sell this set as I am debating a cam now.

19420455

 

Well checked the valve again. Felt spring pressure holding it up enough that it was not hitting the piston. Looked again and did not see marks on the piston so took the risk. When to the junk yard and snagged a 5.3 that was on the row to go out to the crusher and yanked two new retainers, two sets of locks, and two pushrods as they are the same as a ls6. Came home and swapped the springs out on that cylinder. I used the 5.3 locks and retainer on the intake valve. The retainer looked to have taken a hit so its getting junked. But good news its seems to be running fine. The random tick that I thought was an exhaust leak is gone. So maybe it was that spring starting to fail. Got loads of things to get done but early next month I will be swapping the other 14 springs out.

The broken spring that wedged itself. Also pretty sure its a GM spring. So I guess I can add it to the sticky list above.



Cold start. The car has always smoked more out the right pipes than the left. Its something up with the airpump.


Warm Idle

 

Well I already DMed you on Facebook about it. I think head off to check the valves, swap the pushrod, the tray, and change the springs would probably be the most safe option.

Blues are just fine for most applications but PAC would be preferred if the budget allowed.

Might recommend just doing valve stem seals while changing springs since it's not much extra money.

Hopefully it goes well