by Eddie » 30 Jun 2013 20:41
I'm sure you meant .0015 and not .00015 Ade.( 1.5 thousandths opposed to 1.5 ten thousands,,which would be impossible to read without a vernier scale or a digital probe) The bearings are THICKER 90 degrees from the PARTING LINE,,I'm also sure you measured the journal at 90 degrees from the parting line, this is where the clearance is smaller on all bearings. This is because the oil flow in a design like this causes the oil to form a hyrdo-wedge inside the bearing. .0015 is pretty tight,,for performance usage a minimum of .002 is preferred .0025 is ideal. Tight clearances cause the bearing to overheat..losing it's crush,,then it spins taking out the engine. I know you don't want to hear this but it has to be corrected. I measured .0025 on my stroker and specified that exact clearance to the Machinist doing my block work. I would re-measure the journals,,lightly oil the threads on the studs, install them finger tight, if on number 3,(thrust), pry the crank forward as you tighten the main cap. Also some studs may appear longer then others once installed,, this just means the block threads haven't been cut all the way. You can use a bottoming tap to cut deeper threads into the block if you wish, but it wont change anything as far as how the crank sits in the block or the torque settings. I would measure the threads depth with a simple wire gauge, then measure the wire with a vernier caliper. This will show how much thread engagement you actually have. Your thrust clearance should be .006 to .012 tighter is better but not any tighter than .004 Good Luck!
Last edited by Eddie on 30 Jun 2013 20:54, edited 2 times in total.