[Z06] Valve Springs
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
I also own a 2002 Z06- with 33K miles on the clock.
Wanted to replace valve springs and spoke to a very reputable Houston corvette shop (EG in Houston) who told me it would be money down the drain as he has never seen the stock springs fail under normal use.
He also said once you go with aftermarket - you must replace the springs every 25K miles.
Makes me wonder how much the valve spring issue is internet forum chat??
Wanted to replace valve springs and spoke to a very reputable Houston corvette shop (EG in Houston) who told me it would be money down the drain as he has never seen the stock springs fail under normal use.
He also said once you go with aftermarket - you must replace the springs every 25K miles.
Makes me wonder how much the valve spring issue is internet forum chat??
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
So which one of these springs have the closest spring rate to the OEM LS6 valve springs? I'm getting close to rounding up parts for a valve spring swap also, and want a more reliable aftermarket spring that is as close to the stock spring rate as possible.
Thread Starter
Racer
Joined: Jan 2011
Posts: 301
Likes: 0
From: Canon City Colorado
Outside Diameter of Outer Spring (in) 1.290 in.
Coil Bind Height (in) 1.085 in.
Damper Spring Included No
Spring Rate (lbs/in) 375 lbs./in.
Inside Diameter of Outer Spring (in) 0.885 in.
Valve Spring Style Beehive
Comp 918's:
Installed Load: 125 lbs @ 1.800"
Open Load: 348 lbs @ 1.200"
Spring Rate: 372 lbs/in
Coil Bind Height: 1.110"
Outside Diameter: 1.290"/1.060”
Inside Diameter: .885"/.656”
Retainer: TI 772/Steel 774
Part # 26918-16
Description GM LS1 Spring High Load Spring
PAC 1218's:
OD: 1.290
ID: .885
Max coil bind: 1.140
Installed Height: 1.800
Max Lift .600
Load @ 1.800 130lbs
Load @ 1.200 318lbs
Spring rate: 313.3 lb/in
Weight: 62 grams
Frequency: 29277 CPM
PSI LS1511:
Weight: 65g
OD: 1.290
ID: .630
Install height LS6: 1.800
Install height LS7: 1.850
Seat Pressure LS6: 120lbs.
Seat Pressure LS7: 113lbs
Open Pressure: 360lbs @ 1.175
Rate: 384 lb/in
Max lift LS6: .625
Max lift LS7: .700
Coil Bind: 1.100
I personally am going with the PAC springs myself.
Thread Starter
Racer
Joined: Jan 2011
Posts: 301
Likes: 0
From: Canon City Colorado
8th Gear
Joined: Jan 2009
Posts: 8
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Banned Scam/Spammer
Joined: May 2007
Posts: 15,685
Likes: 1,330
From: Machineguns, because I don’t compromise
Also, before you compress the spring, sometimes you have to tap the edge of the retainer (not the valve stem tip!) with a rubber hammer or some wood. Otherwise the spring assembly and valve stem are kinda "fused" together, the locks wont come loose with the spring compressed. One or two good whacks from the hammer will give you a change of tone when you hear it pop loose, then compress the spring.
Hope this helps.
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Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
Sinister-Z ... thanks for the spring spec comparison info in post #43.
Why did you choose the PAC 1218s over the others? Seems the Open Load and Spring Rate of the 1218s is less then the Comp 918s and OEM LS6 springs.
Comp 918's:
Installed Load: 125 lbs @ 1.800"
Open Load: 348 lbs @ 1.200"
Spring Rate: 372 lbs/in
Coil Bind Height: 1.110"
Outside Diameter: 1.290"/1.060”
Inside Diameter: .885"/.656”
Retainer: TI 772/Steel 774
Part # 26918-16
Description GM LS1 Spring High Load Spring
PAC 1218's:
OD: 1.290
ID: .885
Max coil bind: 1.140
Installed Height: 1.800
Max Lift .600
Load @ 1.800 130lbs
Load @ 1.200 318lbs
Spring rate: 313.3 lb/in
Weight: 62 grams
Frequency: 29277 CPM
Why did you choose the PAC 1218s over the others? Seems the Open Load and Spring Rate of the 1218s is less then the Comp 918s and OEM LS6 springs.
Comp 918's:
Installed Load: 125 lbs @ 1.800"
Open Load: 348 lbs @ 1.200"
Spring Rate: 372 lbs/in
Coil Bind Height: 1.110"
Outside Diameter: 1.290"/1.060”
Inside Diameter: .885"/.656”
Retainer: TI 772/Steel 774
Part # 26918-16
Description GM LS1 Spring High Load Spring
PAC 1218's:
OD: 1.290
ID: .885
Max coil bind: 1.140
Installed Height: 1.800
Max Lift .600
Load @ 1.800 130lbs
Load @ 1.200 318lbs
Spring rate: 313.3 lb/in
Weight: 62 grams
Frequency: 29277 CPM
Last edited by ZeeOSix; Feb 9, 2011 at 07:43 PM.
Thread Starter
Racer
Joined: Jan 2011
Posts: 301
Likes: 0
From: Canon City Colorado
Sinister-Z ... thanks for the spring spec comparison info in post #43.
Why did you choose the PAC 1218s over the others? Seems the Open Load and Spring Rate of the 1218s is less then the Comp 918s and OEM LS6 springs.
Comp 918's:
Installed Load: 125 lbs @ 1.800"
Open Load: 348 lbs @ 1.200"
Spring Rate: 372 lbs/in
Coil Bind Height: 1.110"
Outside Diameter: 1.290"/1.060”
Inside Diameter: .885"/.656”
Retainer: TI 772/Steel 774
Part # 26918-16
Description GM LS1 Spring High Load Spring
PAC 1218's:
OD: 1.290
ID: .885
Max coil bind: 1.140
Installed Height: 1.800
Max Lift .600
Load @ 1.800 130lbs
Load @ 1.200 318lbs
Spring rate: 313.3 lb/in
Weight: 62 grams
Frequency: 29277 CPM
Why did you choose the PAC 1218s over the others? Seems the Open Load and Spring Rate of the 1218s is less then the Comp 918s and OEM LS6 springs.
Comp 918's:
Installed Load: 125 lbs @ 1.800"
Open Load: 348 lbs @ 1.200"
Spring Rate: 372 lbs/in
Coil Bind Height: 1.110"
Outside Diameter: 1.290"/1.060”
Inside Diameter: .885"/.656”
Retainer: TI 772/Steel 774
Part # 26918-16
Description GM LS1 Spring High Load Spring
PAC 1218's:
OD: 1.290
ID: .885
Max coil bind: 1.140
Installed Height: 1.800
Max Lift .600
Load @ 1.800 130lbs
Load @ 1.200 318lbs
Spring rate: 313.3 lb/in
Weight: 62 grams
Frequency: 29277 CPM
Honestly... I'm making my decision based on information I have received from others who have used the PAC Springs before. I have also read in my research that the 1218's are a really good replacement option for the LS6 Springs.
As far as the Comp springs go, I personally know several guy's who had issues with Comp springs breaking (not just 918's). This was more so a few years back when Comp was putting out a bad batch of springs which I'm sure has long been rectified by now. I guess that just sticks in my mind for some reason.
The people that I have spoke with that have actually used PAC springs have never had an issue with them and spoke very highly about them. I wish I had more knowledge with the technical aspects between the PAC and Comp springs.
Maybe someone who does will chime in and explain why the three of them have different spring rates yet the PAC and Comp springs are still rated at a .600 maximum lift? This kind of boggled my mind and the only thing I could come up with is that one does better than the other at higher RPM. I could be completly wrong but... your guess would be as good as mine?
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Maybe someone who does will chime in and explain why the three of them have different spring rates yet the PAC and Comp springs are still rated at a .600 maximum lift? This kind of boggled my mind and the only thing I could come up with is that one does better than the other at higher RPM. I could be completly wrong but... your guess would be as good as mine?
Drifting
Joined: Aug 2005
Posts: 1,686
Likes: 20
From: Florida, Hell's Doorstep
Patriot Daul Gold Extreme and Comp Cams High Tech Push Rods , Run Royal Purple and the Cam will not wear one bit !!http://www.animegame.com/cars/Oil%20Tests.pdf
Last edited by ONE BMF; Feb 10, 2011 at 08:04 PM.
Racer
Joined: Apr 2010
Posts: 389
Likes: 25
How the heck does anyone easily rotate the motor in a single person operation? I bought a 24 mm socket for the crankshaft but can't get a ratchet or any other wrench on it for that matter. The steering rack is in the way.
I can't find a shallow 24 mm socket, or offset 24 mm wrench to reach in there. Other than bumping the starter, which I'd prefer not to do, what tool or trick is there to help me? I've tried a strap wrench but that didn't work either.
This has been rather frustrating as all the presumed difficult stuff of removing/reaching plugs and removing plug wires went fairly smoothly.
I can't find a shallow 24 mm socket, or offset 24 mm wrench to reach in there. Other than bumping the starter, which I'd prefer not to do, what tool or trick is there to help me? I've tried a strap wrench but that didn't work either.
This has been rather frustrating as all the presumed difficult stuff of removing/reaching plugs and removing plug wires went fairly smoothly.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
I don't use air, just rotate the engine in the firing order and with the piston at top dead center the valves wont fall more than 3/16th inch. Some people snake a piece of rope in the spark plug hole (with the end sticking out like a tampon string) so as the piston tops out it's got the rope sandwiched between the valves which wont let them budge.
How the heck does anyone easily rotate the motor in a single person operation? I bought a 24 mm socket for the crankshaft but can't get a ratchet or any other wrench on it for that matter. The steering rack is in the way.
I can't find a shallow 24 mm socket, or offset 24 mm wrench to reach in there. Other than bumping the starter, which I'd prefer not to do, what tool or trick is there to help me? I've tried a strap wrench but that didn't work either.
This has been rather frustrating as all the presumed difficult stuff of removing/reaching plugs and removing plug wires went fairly smoothly.
I can't find a shallow 24 mm socket, or offset 24 mm wrench to reach in there. Other than bumping the starter, which I'd prefer not to do, what tool or trick is there to help me? I've tried a strap wrench but that didn't work either.
This has been rather frustrating as all the presumed difficult stuff of removing/reaching plugs and removing plug wires went fairly smoothly.
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
Standing on the passenger side. Use a 15/16" box end wrench,
mine's 14" long. You use a box end that has a "kick" or angled at the end. Another words, not a straight wrench.
With the plugs out, you will be able to turn the engine quite esily. Use a good/strong flashlight & look into #1 hole to see when the piston is at the very top. Oh, it's going to have black carbon on the top of the piston, it won't look all shiney & new. You will still be able to see it, when it's at the very top.
This way your guarenteed not to drop a valve while changing out the spring/springs.
Good luck.
Racer
Joined: Apr 2010
Posts: 389
Likes: 25
I got a hold of a 15/16" offset box end wrench. 15/16 is 23.8 mm which is close enough since I've been unable to find a 24 mm box wrench.
This does work so thanks for the help. I may try jacking the back and turning the rear tires method too.
This does work so thanks for the help. I may try jacking the back and turning the rear tires method too.