MightyBobo

iTrader: (12)

Reposted from the Internal Engine board, for different opinions possibly. Thanks!

Hey guys, I just finished my cam install this Thursday. Got a few hot/cold cycles in on the springs before I beat on it at all past 3K. Anyway, went to Dyno tune today, and the below graph is what I got. Im happy because the little cam I got had great results with no tuning at all. But, the bad side is obvious - past 6100, it dropped in power suddenly. No noises, no knock sensor, nothing at all. Just the power drop. Any suggestions at all? Parts are as follows:

Stock LS1 intake with !EGR.
Crane Cams Z-Cam, 224/224, .551/.551, 112 LSA
Crane Cams Dual Valve Springs
Crane Cams Gold Extruded Rocker Arms (1.7 ratio)
Crane Cams 7.250 Chromemoly Rods (came with the rocker arms)

BTW, sorry - no wideband graph. But, according to the dyno operator, the numbers were fine.

lilbuddy1587

iTrader: (1)

Rocker arms, happens all the time. Springs just cant take the added weight from what I understand.

MightyBobo

iTrader: (12)

Hmm, alright - stupid question then (Im an amateur with a mechanics car 8P), any way to solve said problem? Or is there anything to worry about? I know you'll prolly say go back to stock heh, but I'd like to make the setup I have work before I worry about yanking the studs out heh.

vettenuts

iTrader: (4)

Nope, not the rocker arms, the springs are likely the cause. Two ways to proceed, you can try shimming the springs or you can switch to the new 833 Crane springs.

Who did you get the setup from?

Shoot me a PM, I got your other one.

98SS2836

iTrader: (6)

Same thing happend to me and it was my rockers over powering my springs never changed the springs but went back to the stock rockers and it was fine pulled all the way to 6500 with a hot cam.

Mcduffys

iTrader: (2)

Why would the springs be the cause ? They are crane duals and brand new at that. He has a relatively small cam and it shouldnt be putting any stress on the springs what so ever. Im with the other two gentlemen, rocker arms are the issue.

Haans249

iTrader: (24)

Rocker Arms, and damn, get a LS6 intake, you're killing yourself past 5K rpms for probably 25-30 horse with that LS1 intake lol. Not mention that is where your trq starts to fall too. Nice curve, but with the LS6 intake, you'll get a much nicer one =D.

But like everyone said, its the rocker arms, swap with the stockers and see what happens.

Adrian

rons 00z

iTrader: (10)

why are the push rods so short? isn't the replacement sopposed to be 7.4?

MightyBobo

iTrader: (12)

The crane setup sits a bit lower than Stock.

MightyBobo

iTrader: (12)

Actually, Vettenuts is right. I called Crane to confirm, and they admit themselves that its a Harmonics issue and I'm exciting it. Unless I get the 833 set (which were made to solve the problem), or shim these 832's, Im stuck with the power loss past 6100 heh. But, thanks for the suggestion - LS6 intake has been on my list, but not until I got my new cam in. Thanks for the reply!