Formulated

iTrader: (16)

I see lots of information for the yellow LS6 springs that maximum lift is .575. How much lift has anyone here on this board used with that cam reliably? I know it would be close, but would anyone have enough nerve to run those springs on a Comp XE-R lobe with ~.580 lift?

Hotrodpaul

I have used these springs with a TR220 .553" lift cam with no problems set up at 1.790" installed height. They have about 90-95 Lbs seat pressure and 280-300 Lbs open pressure at 1.230". They should be very reliable and for max RPM, I would run them with hollow stem or Titanium Intake valves due to the lower seat pressure. I limited the max RPM at 6200 for safety and reliability and even used stock pushrods, no issues. Stock pushrods are a safety valve in case of valve to piston contact. For STD weight valves and higher RPM limits and lifts, I would use the Comp 918 Springs set up at 120 Lbs seat pressure.

Paul

Rob

iTrader: (6)

I used them on my old GT2-3 which had lift of .571/.578 for over 15K miles BUT they are super soft lobes. I wouldn't chance those springs with anything more "radical".

Just get better springs and be safe.

gillbot

iTrader: (27)

I read somewhere on a GM bulletin that their max lift was in the .550's but i've seen other people say as high as .575 so I dunno. Honestly, for the low cost of springs compared to a motor, why risk it, just get the best ones you can.

03EBZ06

Agree w/hotrodpaul's data, but PLEASE DO NOT USE 918s'. I just took 16 off my car last night. 10 were broke. If you want to see, let me know.
There are 3 springs on my list of upgrades right now.

1. Comp 921s. better for high rpm
2. Patriot PRC Golds. slightly less force needed to open valve.
3. Crane's geniii dual spring, a perfect spring for hi po apps IMHO.

JUST DO NOT USE THE 918. I HAVE FIRST HAND EXPERIENCE W/THIS PROBLEM.

massls1guy

iTrader: (9)

More info please 03EB06... no info on mods in your sig. Your 918s failed with what cam, after how many miles, how many track runs, etc.

Formulated

iTrader: (16)

Thanks for the info guys. I've been nervous about the 918's. That's one of the reasons why I'm interested in LS6 springs, because they come with a 100,000 mile waranty in a factory car with .551 lift..... Who in the aftermarket can claim that. I just don't know how much farther they can be pushed. I've been thinking that dual spring would be the way to go for high lift, but the added expense of new retainers and seats kind of turns me off. But, you get what you pay for.

03EBZ06

I have had 2 Z06's. The one in my sig, the 03 is not my current car. I gotta update the sig. I now have a STOCK 02 Z.

NOV 06, I put a 216/222-585-116 cam in w/918 springs. Rest of the car is stock. Due to a new project I'm on, I put the stock cam back in APR 07.

The other day I was racing a bike and I noticed after a hard pass, I lost power. I did not hit the rev limter just wound up 2nd to 6500 and heard a snap. Could not figure it out, but engine vibrating slightly but still running "ok".

I thought either clutch or valve springs. When I pulled the valve covers, what I saw was below. 10 of 16 of my comp springs were broken. Keep in mind I RARELY ran the car that hard even when it had the cam in it and rarely tap the limiter on shifts. In other words, this happened under normal driving conditions with a stock engine.

Also, PRC Gold duals are $270 shipped. AND the LS6 isn't as crappy as most think for mild cams. But if you shim them to tension, gonna lose coil bind space.

gillbot

iTrader: (27)

i've been running 918's on a TR230 cam and have yet to have a single problem.

DUSTYWS6

Springs need to be selected based on both lift and ramp rate. Although the LS6 spring may look appropriate based on lift, it will not be suitable for cams that have fast ramp rates.

03EBZ06

I have all the luck.

PREDATOR-Z

EBZ06, you are not answering the right questions
1- How cold was your motor on that day or have you got on it before reaching operating temp before that.
2- Did you heat cycle your springs after install
3- What install height were you running
4- What pushrods were you running
5- What was your preload
6- You are running springs of different kinds in one motor? like together?


What happened is not normal and unless you got a shitty batch, it most likely is related to one or more of the questions above.

03EBZ06

1 and 2, just like i treat a factory spring. I have had a bucket load of aftermarket springs on other engines and NEVER have I seen this. ONLY ONCE on an AFR headed FORD did I break a spring but that was with 650 lift on a 252 duration solid cam at 7000rpm. 1 breaks, yeah ok. but 10 of 16. as you say, shitty springs for sure.

3. stock, 1.8" I believe
4. stock, which are the correct size.
5. about 3/4 turn
6. i was putting the stock springs back on as I was taking photos and to illustrate what a normal springs looks like.

Honestly dude, there is no reasonable explanation except the springs are trash. Also, I would be interested to know of people who have visually inspected their springs and their status

Bo White

iTrader: (59)

Any cam with more than 224 duration and/or more lift than .570" I would step up to a better spring than LS6 Yellows. I ran a 218/222-.562/.566 cam on yellows and it did just fine. Yellow springs are mild so you need to run em with a mild cam.

Formulated

iTrader: (16)

I know what you're saying. Without cam profile data we're kind of in the dark about ramp rates. The best I can say is that if a Z06 cam has .551 lift in 204 deg duration, then a .551 lift cam with 224 deg duration is probably a softer ramp rate. But, they could have some killer accelerations and decelerations to slam the valve open, hold it open, and slam it shut. I just figure that GM probably has a larger development budget and tool chest than any of the aftermarket companies. If there is something from a stock engine that seems appropriate, it's probably worth looking at.