I have a 2002 6sod C5. I was kicking the idea of cams around and I wanted to know what kind of damage they will do? If I update all the valvetrain and necessary components, how long until I start having problems? the car has 35xxx miles and i would probably do a relatively small cam. Thank you.

 

My opinion is that if you start with the right components, and of the best quality you can find, you'll be ok. That includes some good lifters and valvesprings. This is good for a small cam.
On a big cam, basically if you replace your valvesprings every year, you will be fine. Valve springs is what takes the most abuse when running aftermarket cams. You may want to also check your timing belt every year if you have a high lift cam, with agressive ramp, and using your car for competitive racing events. Just depends how you use your car, revving habits, and what not.
-Goose

 

I'm curious about this too, since I plan to do a lot of track days where the engine really gets abused.

When chevy built the z06, they opted for spending a lot of money on lightweight valves just to maintain some reliability with the z06 cam.

If I want to go bigger than that (im starting with a 2002 z06) what sort of reliability downsides are there?

valvesprings/pushrods can be upgraded, but will I still be sacrificing some realibility with a bigger cam? If so I would probably rather pass. Its hard enough keeping a stock LS6 alive on a road course for long.

 

I've read aftermarket cams tend to wear out the aftermarket valve springs every 30K miles or so...

 

If not less than that. If I was in that position, I would replace them every year or 12k miles. That's just an insurance policy well spent.
I have had my Z28 fail on me because drivetrain issues twice, and I've learned a very valuable lesson.

 

Timing belt?????

 

I've been running a Comp XE-R grind 224/228 .581"/.588" cam for ~18 months now. I only have ~3500 miles on the setup. I know someonw else with the same setup and he has ~10,000 miles on his. The research I had done on this subject taught me the springs wear out sooner, actually they break, and the rockers occaisionally spit the bearings.
The reason the springs break is sometimes due to improper break-in, stiffness of the alloy, or some combination. The reason for the rockers failing is usually with a big cam more stress is placed upon it along with much higher rpm's by raising the rev limiter to take advantage of the cam's power curve. There is a 'c' clip that holds the bearings in at the sides of the rocker and it is underdesigned for this purpose. One solution is to have Harland Sharp rebuild them by replacing these 'c' clips with stronger ones.
Having said all the above I also read that certain springs have longer life than others. This is just empirical observation, but it seems to hold water. The heads I have are AFR's and had Patriot Gold dual springs installed. These have shown almost 0 breakage since thy have been introduced and I have read there are some still running them with over 20k miles on them. I personally will check my springs at 10k miles and then every 2k or so after that. Because of the stiff alloy.
The last thing that was discussed was the timing chain. If you are changing the cam you most certainly should change the chain to a heavy duty one. The stock one has been known to fail under hard driving conditions and I can tell you it is pretty flimsy. I replaced mine with a JWIS, and the LS2 chain is also a vey good bargain.
The bottom line is even if you spend the extra money and upgrade with the best components you will be decreasing your reliability IMHO.

 

Im sorry for the stupid question, but how much are new valve springs? Thanks for the replies

 

Comp 918's for a small/large cam are like $160. Im getting my cam installed here soon and i plan on upgrading the springs MAYBE once every 1.5yrs if that. Im going with a huge cam too, a 238/242 .603/.609 on 113lsa

just go big and dont look back, you will love the huge power increase.

 

With a lift over .600 you might want to go with 921s, duals. New seats, seals and make sure you do new rods too as IMO that helps a ton too. Biggest thing with springs is warm up as they tend to be brittle when the oil is not up to temp. Let it idle and get the oil warm, then keep the revs down untill it is up to 150, then enjoy.

Original post, well, for the most part here, if we go internal to the motor, we are probably doing lots of other mods too. Make sure you updgrade the springs, seats, retainers and rods and check the spirngs often IA/W your use and driving. A good warm up helps with springs too.

Bluff: same as an LS1/LS6 IMO with the right precautions (springs, retainers, seats, rods and warm-up).
Dave

 

I was reading over in LS1tech and talking to several engine gurus.

for normal street driving your fine. for a new cam, of anysize and if your do track days, DR change the spings once a year.

Dont get too big a spring either.

 

Is 224/224 .578 114LSA cam too big? No racing..normal driving.

 

thats a pretty mild cam, a lot bigger than stock, but not to big. that will be good for street driving and your car will run good if you get it tuned right.

 

my 98 only had around 40000 when i did h/c package did not use no cheap parts first tune was bad had retuned some where else ran fine but rev limiter was set to high imoi had a 3rd gear miss shift then rod started knocking with only around 43000 pulling eng. now for a forged short block hope to be back driving soon miss the power

 

Thanks for your input and that is my plans exactly A sleeper..nice mild sound but power when need be...

 

I put in a big cam at 45K on my 2003 Z06. It is 245/245 .600/.610 lift on a 112 lsa along with Comp 921 springs, seats, seals TI retainers and hardened rods. I changed heads at 75K with new 921 comp springs TI retainers etc... Car now has 90K with no issues at all. I would say that done right there is no reason for a 'big' cam to negatively affect engine life. I drive my car >100 miles daily. I plan to get new springs at 95K just as a precaution. Good Luck!

 

That cam spec is almost identical to the TSP MS3 except the MS3 is 237/242

 

Is that the duration specs on the G5X3?? I thought it was smaller than that?

 

I have Erson valve springs, old school, nobody hears of them anymore. They were put on in 2000, 20,000 miles ago. With a mild lift/duration cam their tech dept. says they will last as long as stockers. I hope they're right

 

I have taken a very conservative approach and used the best parts I could find. I have a VHP cam 216/224 .551/.551 115 LSA with Crane 1.8 rockers and Crane dual valve springs with titanium retainers. I also installed the Katech (JWIS) timing chain which is a single chain that the C5R used. I installed the GMPP timing chain damper and an ATI harmonic balancer which is pinned to the crank. I used an ARP balancer bolt installed with ARP Moly lube (no loctite) so it can be easily removed. ARP cam plate and cam sprocket bolts.

This year, I am installing Dart heads and moving to Crane 1.7 rockers. Dart heads have drop forged valves, PSI beehive springs, titanium retainers and machined locks. I will install these with ARP head studs and Morel lifters (these took three months to get).

Once we get into the better weather, back in to the motor. But as stated above, once you go with high performance parts maintenance is key as well as how you drive it. Stiffer springs result from higher strength (higher stressed) steel so fatigue life can be an issue. Failures can be catarophic so preventative maintenance becomes necessary. I will likely change the original PSI springs on the heads at 10K miles only because I don't have much statistical data on them as far as life is concerned.