If you really want to play it safe, you could drop the head on with no gasket, but with 0.080" to 0.100" flat washers under it at the locations of the few bolts you snug down. (Make sure to eliminate any valve lash, perhaps with a feeler gauge under the rocker tip) If the clay shows more clearance than the washer thickness minus your intended gasket's thickness, you can discard the washers, install the gasket and carry on in the certain knowledge that you won't crush the snot out of the clay...

 

cam specs? why haven't these been given yet?

 

I would be giving cam specs, but I can't as its a custom cam from Ed Curtis (EDC) =). I asked him how much I would need to flycut, but he just told me that I have to mock up my engine and check...which he's right.

I found a couple good writeups online for checking P to V using the dial indicator, which is the most accurate method. And it was explained well, so I'll use that method when putting together my engine to check the flycutting distance if needed.

Now, I've been thinking long and hard about this, and I have one concern right as of now.

In the tutorial that we've all seen, they say that you need to put the piston to TDC when conducting the flycutting. Now, I'm wondering if this will yield the proper outcome because...
the most likely point of interference is when the piston is somewhere below TDC and because the valves run at an angle to the top of the piston, wouldn't that actually move the required position of the notches lower on the piston then what was cut if the piston was at TDC? Or is the angle so small that it really doesn't make a difference where the piston is when you make the cut?

Thanks,
Adrian

 

I believe the most like point of interference to be at the end of the exhaust stroke. The piston will be chasing the exhaust valve closed and the intake may be open for scavenging on a long duration (overlap) setup. Therefore, TDC would seem the most likely place to run into trouble. For these reasons I would flycut at TDC.

 

You are right about tdc being correct place to notch pistons but, I and others have used stock head and cutters are larger than actual valve size to notch piston below tdc and had good results.This is because larger cutter makes it turn out. Technically you would need head with seat cut out completely to assemble cutter and cut at top dead center.We did not have this and it still worked out.

 

Makes sense. Because the piston is down the bore a bit and the valve is typically at 10 to 23 degrees off the vertical, the valve/cutter moves further across the piston before making contact, thus the cut starts too far over to clear the edge of the partially open valve at TDC. By using a larger diameter cutter, the cut is moved enough to compensate.

 

Hey all,

I didnt find it worth opennin a new thread over the same topic but i would like to know if i need to have valve relief slots for this cam
229 / 229 @ .050, .576 / .576 lift, 116 LSA
I am currently runnin a Stock lower end LS6 with LS6 GMPP high compression heads (60.9cc)and MLS head gaskets. My current compression is 11.59:1

Thank you for your time