piston/valve clearances

[fallonmi]

I am in the later stages of a rebuild of my 3.0 SC engine. I am checking the piston to valve clearances. I had all new valves, seats reground, and heads resurfaced. Because of the resurfacing, I made sure the deck height was on the high side. On bank 1-3, my clearances are tight. Exhaust is about .75 mm and intake is just over 1 (~1.125) mm. Clearances on bank 4-6 are similar. I fear I have to rip everything back down and install thicker gaskets, or will I be okay with these clearances? I don't race my car (ever) if that makes a difference. Any help is greatly appreciated.
-Mike

[fallonmi]

I have also installed 964 cams, if that makes any difference with the clearance.
Thanks.

[Wayne 962]

Way too close, this engine will self-destruction (likely) when it's warmed up.

You need 1.5mm on the intake and 2.0mm on the exhaust.

-Wayne

[cstreit]

How did you measure it? Plastiguage? Valve adjust screw method?

Before you tear down, let's make sure the measurements are correct?

[fallonmi]

I used the adjustment screw method and followed the procedure in Wayne's rebuild book. I removed the tightening nut and tightened it to the point of resistance (contact with the valve). I then marked a spot on the rocker arm and the adjustment screw, to ensure I would come back to the same spot each time. I took frequent measurements and got a minimum clearance of 3/4 of a turn on exhaust and 1 1/8 of a turn on intake. I took these to be .750 mm and 1.125 mm, respectively. Did I do this correctly? I would REALLY like to avoid tearing this thing back down to add a thicker base gasket.
Thanks.

[fallonmi]

the left bank of cylinders had the tolerances listed above. The right bank had clearances of 1.25 for intake and 1.125 for exhaust. Will I be okay with these on this side so that I only have to tear down one half of the engine?

[Groesbeck Hurricane]

Mike,

See Wayne's post. You must have: "You need 1.5mm on the intake and 2.0mm on the exhaust." It is only prudent.

[beepbeep]

You can also machine groves into the pistons...

[cstreit]

You didn't mention turning the crankshaft. Are you sure the rocker was fully on the back of the lobe when you set the screw?

[fallonmi]

I will double check to make sure they were on the low point of the camshaft. I set the clearance to zero at 0 deg, TDC (not at valve overlap).

[cstreit]

Not trying to make you do more work, but hopefully it will be something easy rather than more machine work...

[fallonmi]

Well, I double checked them. I am still getting the same thing. I ripped the engine back down to the case. I am just going to install thicker copper base gaskets to get the clearances I need. I guess it was just unavoidable. Thank you for your help.

[cstreit]

Good luck. Good thing you checked!