jason5

iTrader: (2)

i have a friend who wants to get a little more lift out of his cam with 1.80 ratio rockers, his current lift is 566/568 and if my calcualtions are right it will make his new lift 599/601, will his pistons need to be flycut for this setup, he has pp stage 2 heads stock deck height, not milled. he's trying to find out if this is to much lift or he could do this with out flycutting

TheBlurLS1

iTrader: (8)

depends alot on the duration/LSA of the cam, post up the complete specs of the cam, with respect to the 1.7 rockers.

racecar

When P/V is going to be close, it's not worth the risk to guess. If you have ever had a weak valve spring and had a piston kiss a valve, it really creates a mess. I hear many references to clay on the piston for measuring. That method works, but I found it hard to measure the clay, and you have to remove the head. This is what I do when building a new motor. It may work on your car. Install the new cam, with the head on. Replace a valve spring with a 2 pound spring, set the lash, then turn the motor in 2 degree incriments. With a dial indicator on the top of the valve spring retainer, you can push down the valve (rocker arm) until it contacts the piston, read the indicator. Turn another 2 degrees, test again, etc. You will find the part of the cycle where it is close, and know exactly what the clearance is. Be sure to check intake and exhaust.
Racecar
"Better safe than blown to pieces"

jason5

iTrader: (2)

222/224 566/568 112

Nate_Taufer

iTrader: (1)

duration causes p-v clearence issues, not lift. plus if the cam in question has xer style lobes you're not gonna be liking changing springs.

Nate

LS1_PNYTAMR

iTrader: (1)

for the price of most rockers, id call one of our sponsors---------->

tell them what heads i had, and have them custom grind me or suggest one of there cams to make the most power, and clear fine, and ask if u need new springs..

u will prolly make more power this way, not spend anymore money or time checking stuff, and will prolly make more power since its matched to your needs, these guys own there own shops and earn our trust and respect and most importantly our money ofr our reason, so they go thru the checking and finding out what works and the headaches that come with it for us to reap the rewards!

Byter

iTrader: (1)

The problem with NOT checking, even with a vendor's suggestion, is that LS1's can have almost a .010 variance in how much the pistion comes out of the bore. A vendor will need to take this into account. Obviously, they can work with a fudge factor of .010 and base their calculations on that. However, you may be giving up some compression, duration or lift.

When installing my H/C package, I went the route of measuring everything, deck clearance, PTV clearance (with light spring and dial-indicator), and degreed the cam. Maybe it's overkill and adds a day to an install, but I know what all my important measurments are, I know that everything installed is what I wanted, and got a good education on engine building. To me, very much worth it.

Ben01C5

What kind of power are you putting to the ground with your set-up?

PREDATOR-Z

A cam spends very little time at maximum lift. The usual benefit to a 1.8 is to add lift, but it does it at all lifts.
Here comes Crane rockers 1.79 rockers (accelerated variable). It will give the higher lifts when most wanted, like up to .250 but after that it goes down to finally reach 1.72 at .600 only to repeat on way down.
I would recommend Crane 1.79 rockers.

Byter

iTrader: (1)

Ben, are you asking me? If so, I don't know yet. I haven't been able to get to a dyno and have the car tuned. I will have to wait until I get my taxes done to see if I have any spending money left!

I can tell you this. My last dyno with my 4 yr old H/C was 355 RWHP/ 355 RWTQ. My SOTP dyno tells me I have a lot more than that!