Hi Rey, Nothing special on the CART clearance just standard 2 to 3 mm. Those engines have paper thin pistons and cams with BIG lifts and LONG durations. To top it off they run on Metanol so High Compression ratios are standard, and they reved to 14K+. So, not much room for any extra freedom for the valves. The interference promblems can come from a combo of block/head expansion and high inerta from the revs. While expansion normaly increases the clearances it can take the clearances away if it changes the timing of the cams. Like I said,,, lots and lots of stuff goes on at the same time in engines. To measure this stuff hot, you have to run heated coolant and oil thru the motor while turning thru by hand and depressing the valves till they touch and recording the measurements at regular degree intervals. Not something that you need to do unless there is a big problem somewhere as it is a lot of trouble to set up and do. Robert Costa Mesa _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. ............................................. To unsubscribe go to http://www.sayegh.org/unsubscribe.htm .............................................
