Freaklt1

I bought a cam set up from a popular engine builder on CZ28 and the cam has a lot of lift. He supplied me with 918 springs which will supposedly hold up to this kind of lift even though they are only rated to .600. If they do hold up, how long will they last in a car that is daily driven 15k per year? Will they even last 15k? BTW, this is an LT1.

JZ'sTA

iTrader: (23)

In all acturality they should hold up fine.
Most people use the dual's for piece of mind.
You will probally almost never see that much lift.

blkZ28spt

From what I remember reading they should hold it alright. I'm pretty sure they rate them a little on the low side as compared to what they can actually handle. Then again I'd just feel a lot safer with a dual spring. It's entirely possible to break one.

Taspeed

iTrader: (1)

you will probably wear them out in 10-15k. I had a set on a .591 lift cam that lasted me 30k but they were absolutely worthless when i tested them. I never broke one, but I don't think I would go that route again.

Brett H

iTrader: (2)

Though I don't have any personal experience with that high of a lift on 918's, my opinion would be to go with 921's or some other type of a dual spring for piece of mind. Yes, the 918's will likely hold up for 20k miles but there is always that what if..... For a few extra dollars invested now you could save yourself a ton of headaches if a spring ever let go and took out a rocker or 2, maybe bent a push rod or possibly bent a valve. Just my .02.

Freaklt1

I really don't know what I want to do with this thing. I can't believe that he sold me a cam and insufficient springs. He would not give the specs of the cam until he had my money and I really don't want to have this much lift. I will constantly be worry about my springs breaking or wearing out. I think I may have to just sell the entire setup.

MikeB.RamAir

like the other guy said you will be alright with it holding up but vavle float at higher RPM's will most likely happen

PREDATOR-Z

First of all this is a LT1 not LS1 so 7000 rpm on a regular basis is unlikely.
Second of all, the 918's will control valve float better than any dual as they are designed for better harmonics and proven so.

The trick is to have them installed at proper height (measured for proper specs).

In all you will have to test them as regular maintenance ~12>15K (that is true for all aftermarket spring).

There is no way any spring can be slapped in and just last as long as stock ones on low lift cams. If you do not want to mess with modding maintenance then DO NOT MOD.

The 918's will handle such lifts with proper valve geometry. They are one of the BEST springs out there.

Here is a link that explains how they differ and work from other springs:

http://www.krcperformance.net/newcontent/beehive.html

RedHatRdRacer

iTrader: (25)

DAPSUPRSLO

iTrader: (14)

Run them, you will not have float and they will last just fine.

Unaffliated Racing

iTrader: (15)

Werd..untill a few months ago I thought I was the only voice of reason on these springs. It's the only spring I personally use and I use it on every application I can. I have a current deal me and my buddy are doing on a SBC..soild street roller...610" lift, street car.

Thanks,
Brian

MikeB.RamAir

I know you ment well but you came off sounding like an *******
its just what I thought guess I dont know as much as you

hoserack

610/612 lift here running just fine.
918 springs rock.

Avengeance

iTrader: (4)

Dont even worry about it.. like its already been said.. Ive heard of people pulling them after several thousand miles to only discover they spec'ed better then theyre supposed to stock.

BeefTip

I heard from someone on here that they used to be sold as a .650 lift spring....I could be wrong though.

PREDATOR-Z

LOL, far from it, sorry if my writing style is a little "dry" sometimes.
They used to be advertised till .620 untill the 921's came out, then they advertised them as .600. Hmmm, I wonder why???

Cal

iTrader: (1)

They must have thought no one would shell out the big bucks for their duals if there singles were rated for almost as much lift.

PREDATOR-Z

Yeah, that is what I think too, I just was a little sarcastic.

CaptUSA

iTrader: (5)

Why would you ever buy anything like that without knowing what you were getting first??

FWIW, I bought a cam from TR that held .600" on the exhaust side, and they recomended the 918's. I took a lot of grief from the boards about how I was going to gernade my motor, but the guys at TR really know their stuff. If you're going to worry about it, just sell the 918's here on the boards. You'll be able to get a good price if they're NIB, and use that money and a few extra bucks to get the duels.

Good luck to you!!

Gman2002Z06

I'm running the 918's with my G5X3...Approx. 4000 miles so far and running perfect...6800 rev limiter...No worries here...

Peace...Gman