Piston to valve clearance question
 

I am coming down the home stretch of my rebuild... I want to be sure I get this P to V clearance thing correct.

Have Euro P's and C's with only .003" taken off the heads to clean them up. The deck height was well withing the limiits. I used a .25" cylinder base gasket and putting in 964 cams.

Using a dial gauge for an accurate measurment, at TDC on piston #1, if I have three + plus full turns of the screw until the valve touches the piston on the intake side, should the clearnace be okay? Three turns measured 3mm... is this correct? Would that be too much space to expect at TDC? What would the approximate difference be at +10 degrees past TDC?

I measured the exhaust side and found approximately the same... a little more than 3 full turns of the valve adjustment screw.

I'd appreciate any advice you have, just to be sure

Thanks all....;)

V to P
 

The thread pitch on the 911 rocker is 1 mm per turn so that makes it easier to calc., on the intake test it at aprox 10 deg. ATDC for a min. of 1 mm, and the ex. valve at aprox 7 deg. BTDC for a min. of 2- 2 1/2 mm at this position the valvas are closer to the piston than at overlap, they will vary a little from cam to cam but that will get you very close. also set the valve lash at almost zero then add the lash to the clearence when you are done.

Have fun, Mike Bruns JBRacing.com

Mike is right, measuring at TDC is useless. Otherwise, one could figure out the clearance with out installing the cams and timing it up :) that would be sooo much easier. I'm right where you are and will be timing and checking this week. I see the light at the end of the tunnel!! I just hope it isn't a train ;)

Best regards,

Michael

Thanks guys... appreciate the guidance.

Is there any way to easily measure 10 degrees on from TDC on the pulley (thinking back to my days in school with a protractor, etc!).

degree calc.
 

Your pulley should have a 30 deg. mark for timing that you can measure from Z1 and divide that by 3 and be close enough, just use a caliper or a divider and re mark the pulley with a sharpie
Mike Bruns

Perfect. Thank you!