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An exciting day today. I picked up my block and rotating assembly and now ready to build. THis is my first complete re-build.
Can someone tell me the proper orientation of the Rods? Should the portion of the rod with the two bearing tabs be facing the outside of the block? This is how the engine came apart, but I have little confidence they did anything right.
The tabs for the bearings on the rods will all be put torward the outside of the block. Big block pistons are all rights, so to ease your mind
pick up all eight rods pistons, with it in your hand and the tabs torward
the outside of the block when you look down at the top of the piston
the intake valve notches should be to the righthand side of the piston.
as long as all eight pistons are mounted on the rod that way your good to go.
bearing tabs to out side of block, all intake valves on the right side.
Last edited by Little Mouse; Apr 9, 2008 at 11:38 PM.
Put the rods, pistons, bearings in it first without any rings snug up the rod bolts a little check the side clearance. You may need to switch some rods around to pick up more clearance on one set.
Last edited by Little Mouse; Apr 10, 2008 at 03:10 AM.
An alternate approach is to measure the rod journal pairs and the rod journal width with vernier calipers before installing the pistons - you really don't want to have to pull them out if you don't have to. Just push the rod big ends together and measure, then the same for the journal, being sure to measure to the machined surface off the chamfer.
A micrometer's not required for this measurement as anything +/- a couple of thousandths is close enough. Unless you find something on the boundaries, you're good. Of course, you still need to check with a feeler gauge to be *sure*.
An alternate approach is to measure the rod journal pairs and the rod journal width with vernier calipers before installing the pistons - you really don't want to have to pull them out if you don't have to. Just push the rod big ends together and measure, then the same for the journal, being sure to measure to the machined surface off the chamfer.
This is the method I use except I use a rod-vise on rod pairs so I can pair them up before piston installation. Method is essentially the same - measure the journal width as described - measure pairs of rods in a rod-vise - a little bit o math later - label rods and install pistons....
you can do this with pistons installed (on the rods) too if you absolutely must.
I also stamp my bearing and side clearances in the pan rail so I can compare clearances if I ever have to do a teardown.
Yep, ideally this is a spec you know before the pistons are mated to the rods and should be part of mock-up.
With pressed pins, they'll come back with the pistons in place and then it becomes a matter of making the best tolerance stack. In this case, I measure each rod and each journal, then "do the math" to find the best stack for each journal (as the pics show). Keep in mind that you can only swap between bores in the same bank.
Whatever way you do it, check side clearance first don't torque any rod bolts up then decide to check side clearance last, at that point if you need to move anything around you have torqued the rod bolts one more time for no reason.