85Firebird350

iTrader: (3)

I just Bought AFR 210cc's with 66cc and it says max lift is .670. I also bought a Lunati Voodoo Mechanical Roller Camshaft with.585''/.600'' ,Adv. Duration is 278°/285°, Duration @.050 is249°/255°. But with my stroker engine and such a big cam am I going to have to worry about valve clearance. i dont want to mess up my engine. Theres been a lot of money put into this and I dont want to break anything because of too big of a cam. Oh yeah and I have 5.7 rods.

Apeiron

The only way to tell for sure is to try it and check the clearance.

85Firebird350

iTrader: (3)

I was hoping to find out without putting the cam in so then If it is too big of a cam I could just sell it brand new unopened for about what I paid.

ede

other than checking all you can do is guess. i'll guess it'll be ok, then again if it isn't i'm not going to be out anything. another option if there is too little clearance is to increase the clearance and keep the cam.

F-BIRD'88

Come on. Throw the cam in and fire it up. I want to see all those expensive valves bend....Then you'll be asking if you can straighten them out with a hammer .

doc

Do it right, buy a valve clearance checking tool. You can loosely bolt down the new head, leave in the old cam, and check the valve clearance with that special tool, or use modelling clay. I recently used modelling clay because I had not yet permanently bolted down my new heads.

F-BIRD'88

Do you have a dial indicator and magnetic stand?
Same as used to degree in a new camshaft.

85Firebird350

iTrader: (3)

No I don't have a dial indicator or anything. I guess I'm going to have to put everything in and hop for the best.

F-BIRD'88

Why? Dial indicators are not expensive.
What you want to do is mock up the motor as it will run except without the head gasket installed.
Then adjust the valve lash of say #1 cylinder to exactly Zero Lash on both the intake and exhaust.
Then set up the dial indicator on the valve retainer and turn the rocker nut further from 0 lash until the valve opens .060". Then do the same for the exhaust.
Then do the same thing to a cylinder on the other bank. Say #6. Now that one cylinder's from each side of the motor has its valves cranked open .060" past the 0 lash point you can rotate the crank shaft over SLOWLY BY HAND twice. If there is no interference, You are good to go.
You have at last .060" clearance between the retainer and seal at full lift and at least .060" further spring travel before coil bind at full lift. You also have at least .060" +The valve lash (.016 to .030") + the gasket thickness (.040") of net total valve to piston clearance. Don;t forget the go back and properly re adjust the valve lash before fireing it.
You must set the vlave lash at 0 lash with that cam lobe on the back side (base circle) of the lobe.
use the intake closing, exhaust opening method to position the crank for this adjustment.
Is there anything you do not under stand?
it will cost you far more to rebuidl this motor if there is valvetrain inteference than the cost of the dial indicator. it won't be pretty. You'll find lots of other uses for the dial indiator.

85Firebird350

iTrader: (3)

None of that seems too hard, I'm just 18 so I don't know too much about doing valve lash and things with my car. I'll have to get someone more technical and knowledgeable to help me.

F-BIRD'88

There is a invaluable hard cover book called "Fix Your Chevrolet". Find a copy and buy it, steal it, what ever. Read it, know it. There will be a test......

5678TA

well to give you a rough idea, i have a .592" lift, 260* @ .050" solid flat tappet cam(with 1.6's).. from piston to head, its .040".. .025" deck and .015" gasket.. plus heads are milled .020".. i run fine with .020" lash.. no problems whatsoever..

is your block Zero-decked?? what head gasket thickness?? you should be fine with that cam.. i would only be worried with over .600" lift WITH valve lash..

F-BIRD'88

Te fact that your flat tappet cam clears is no indication that a particular roller cam will clear in someone elses motor.
The lift curve action when the piston is nearTDC is a lot different on a roller profile.

many Harbor Freight type stores Summit, Jegs, sell dial indicators and the magnetic stand for very reasonable prices. threr is no excuse the not check and verify valve to piston clearance on this one.
You'll find a ton of other uses for the dial indiator, or just sell it when you're done.
The camshaft is worth just as much money wether The box has been opened or not.....