Adrenaline_Z

N/m , read that wrong.

What is coil bind on the current spring?

Dixit

iTrader: (1)

112lbs @ 1.800
352lbs @ 1.150
will handle .650 lift with .045 coil clearance

Thats the specs on the Crane Dual spring setup. So coil bind should definetely not be an issue. Not to mention I put well over 25k miles on the Crane Dual springs with that cam and no problem except the one you saw pics of.

Dixit

mrr23

iTrader: (3)

you do not need taller valve covers. just need to grind some on the inside to clearance for them.

bigdsz

iTrader: (1)

112 @1.80 is way too low seat pressure, with a 228/230 you should have a minimum of about 130. At the very least those springs need to be shimmed. If I were you I'd take them off and run a more acceptable spring. Do a search and you will find virtually no one runs a cam that size with that light of pressure without shimming.

Dixit

iTrader: (1)

Interesting cause quite a few people run the Crane Duals on aggressive cams and have no problem. The guy at Crane when we bought the cam said these springs are the ones to go with. Those specs are what I got off the CAM sticky.

Also on my dyno charge I show no valve float because it climbs all the way to 6800rpm without a problem.
http://www.turbofedmax.com/Z06vette/HPTuner/414whp.gif Thats one showing it cutting off before 6500, but on another chart I got it does not trail off, the HP holds solid at 6800rpm.

Now im confused because I thought these springs were more than enough for that cam espcially since the Crane salesman mentioned it, yes I know they could've been BS'ing but I know a few others that run these springs on cams around my size and no problems.

Dixit

gmblack3

iTrader: (1)

Did you talk to the tech support at crane to see what they said? Maybe thats who you talked to last time?

CAT3

iTrader: (9)

If I were a Crane, or any other Manufacturer, rep, I would try to sell you on my parts as well. Good thing I'm not a rep.
I would NOT get more Cranes, either PP Gold Kit, or PRC Spring Kit. As for rockers, I want to switch to the Harland Sharp Modded Stock Rockers offered through Nate.

Spinmonster

I noticed that you are running the old springs without the stripes. The new ones are much better and crane will give you a deal on them if you call with your issue. They did it for me.

Dixit

iTrader: (1)

Right, but are we still saying here that the Crane Dual springs is not enough seat pressure for the Crane cam I have?

Dixit

Mark Campbell

With stock rockers (that start the valve off the seat and return it to the seat at a ratio of 1.54), you would probably need to shim the springs to about 130# because of the lack of leverage of the stock rockers putting the lifter back on the basecircle (1.54 ratio X 130# of seat pressure = 200# of force on the lifter). With the Crane rockers you don't need as much seat pressure because of the better seat ratio (1.79 for 1.7's and 1.89 for 1.8's: 1.79 ratio X 112# of seat pressure =200# of force on the lifter; 1.89 ratio X 112# of seat pressure = 211# of force on the lifter) We have tested this extensively over hundreds (probably thousands) of tests and know that this works! Hope this helps!

Mark Campbell
VP, R&D, Crane Cams

bigdsz

iTrader: (1)

Go to JRP's cam help guide Sticky thread in the internal section at the top of the page. You will note that the most popular springs Comp 918, Patriot , PRC and Comp 921 all have install pressure of at least 130 lbs. Call or email Brent at TEA he will be happy to enlighten you.

Dixit

iTrader: (1)

So with the stock LS6 rocker arms I would need to shim them. Now with the stock LS6 rocker arms am I still getting full .600" lift with the 228/232 .600 112lsa cam? Or do I need the Crane 1.7 rockers to do that for me? See I really dont want to flycut the pistons if I dont have to. Ive had the stock rockers on this cam for 25k miles and no problems thus far. I honestly dont want to replace the rockers if there is no need or benefit.

Dixit

Mark Campbell

The stock rockers start the valve off the seat and return it to the seat at a ratio of 1.54:1. They achieve 1.69 ratio at about .400" net valve lift. Our 1.7's start the valve off the seat at 1.79 and the ratio decreases (as the valve opens ) to 1.72 at about .300-.350 net valve lift. This process is reversed as the valve closes. This gives you approx. 7deg more duration at .200" valve lift than the stock rockers while maintaining the same seat to seat timing. You don't have to use Crane rockers, but the 1.7's are a proven 15HP over the stock pieces. You would probably have p to v clearance problems with the 1.8's. You will probably get about an extra .009" lift over the stockers.

PREDATOR-Z

Look at your cam card, it says lifts with 1.7 rockers. So .600 being max lifts on you cam, yes that is the lift you're seing.

bigdsz

iTrader: (1)

Dikit, forget the smoke and mirrors, the stock rockers with their light mass are more than satisfactory for 99% of the applications. I has been proven time and time again the heavier rockers have more inertia and are more prone to valve float. Also if you want a cam with more lift and duration buy a bigger cam for $350 instead of rockers for $700.

PREDATOR-Z

yeap i agree

Mark Campbell

FWIW, Crane rockers only weigh 5 grams more than stock, are 50% stronger with much less deflection and have essentially the same moment of inertia.

Spinmonster

BS

With the shorter included hardened pushrods there is no weight difference for the total moving mass. 7.4 hardened pushrods weigh more than the ones that come with the kit. Net weight is the same and I will take the cranes before the stock crap dumps its bearings. Not to mention the fact that there are guys revving to 7500 with yella-yerra rockers that weigh a LOT more than stockers such as PHIL97SVT who is about to break into the 9's with a 150 shot in a stock displacement motor.

I don't see the issue with putting in shims. It takes a second to do it when you install the hardened seats and cost is a whopping 9 bucks for the shims from S&K speed where I got them. The result is a great DUAL spring that is good to over .650 lift. If you have ported heads that had the valve seats redone, you better have shims or at least have checked the install heights of the springs. I bet half the spring set-ups out there are in need of spring shims on some of the springs but it was never checked with a micrometer and assumed they were al the same/perfect on install. It is part of the work that is supposed to be done for every install and companies that set-up heads do it all the time. Assuming all springs should have 130lbs seat pressure with 1.8" install heights is just silly misinformation. They also wear out at different speeds so the seat pressure you think you have is probably not even too spring to spring. Cranes and all springs should be adjusted to your application. The cranes don't have to be shimmed in all applications.

If you are running any motor with single springs you are taking chances.

Smoke and mirrors or just a step everyone skips because they don't realize that valvetrains are adjustable and these things are always part of a motor build up. Its an expensive learning curve going with stock rockers and single valvesprings.....you can keep them....I already had to pay for one forged replacement motor.

bigdsz

iTrader: (1)

I stand by my statement that OEM rockers wiil suffice for 99% of LS1-6 applications. The Crane rockers are simply overpriced. Further, I disagree that 112 lbs @ 1.80" is sufficient install pressure. Do you think there is a reason that Associated Spring and Comp control such a large sector of the aftermarket spring trade? I think they've built a better mousetrap. I'm also not just dumping on Crane, I think the Comp 921 spring kit is a ripoff.

DanZ28

iTrader: (5)

There is nothing wrong with shimming a spring to the correct spring height. There are cams that would be fine at 112# seat pressure but most will require more. It was suggested earlier to shim the springs to 1.770 height, I would look into that. There are plenty of cars running these springs on much bigger cams with no issues. Since you have to replace the springs, for ease of install, I would look into buying a spring with a better seat pressure out of the box. Like recomended though, measure ALL your spring heights. If going with new heads, you may no longer have a 1.8" install height to work with as I found out. Different valve jobs, different valves etc. will can change things in which the Cranes worked out well for me since I got 1.770 spring height without any shims. Good luck!

Dan