Grinding The Crankshaft Rod Journals - Spun Rod Bearing - '68 Firebird 350 Engine Rebuild - Pt 6

Okay, I'm checking to see if the crank is bent or warped. And just looking at the needle there as I move the crank around, roll it around. We probably don't have even two thousandths run out in that crank. So that's plenty good. We'll grind it right there where it is. We won't have to do any straightening on it. Since, let's see, what was this journal right here? Number, what would that be number? It's actually number four on a Pontiac. I had a spun journal and a lot of times when they do that, they get hot and then the extra pounding of the bearing on there, they will be warped. So I would not have been surprised at all if this crank had been warped. But it runs very true. Won't have to do anything to it at all. I just got done grinding the 454 Chevrolet crankshaft in here. 454 has a four inch stroke length. Now I'm going to do the 350 Pontiac, which has a three and three quarter inch stroke length. So I need to adjust these chucks from four inch diameter down to three and three quarter. You do it through half the diameter, or yeah, half the diameter, the radius. So I need to move from two inch radius down to inch and seven eighths, which is 125 thousandths. So I've set my gauge here. Full scale, 120 thousandths. Here's plus five here, 125 thousandths. And I'm going to back off that stroke length until this gauge is on zero. Okay, there I am. Zero, zero. Move over to the other side. Do the same thing. And zero, zero on that side. With that, I should be able to mount my crankshaft. I don't know if any of you people have noticed this, but over the years, cast iron has gotten heavier and I found myself having to use the hoist here for these smaller cranks that I used to just lift in by hand. Crank major is 25 inches long. I should slide this one tail stock in just a little bit. Okay, we need to index the crank into the machine. And we use this v-block here. Crank is loose in the chucks and just rotate it just a little bit so it's in the v. Lock the chucks down. May have to change the balance just a little bit here on the counterweights. Which we shorten the stroke up here. So what happens if it's not balanced? It makes the crank kind of flop as it comes around. It doesn't run steady. The belt that drives this would first be under tension and then as it goes over center, it would slightly jump forward if there's any slack in the belt at all. So it's just good to have it in balance so it's not trying to go the opposite direction all the time. Okay, so this journal here is our worst one. We want to start on that. Figure out what it'll clean up at before we move on to the next one.