I'm rebuilding a 4bolt main 350. This is my first motor I have rebuilt. So im trying to figure things out. I'm putting in the pistons and rods and I don't understand side clearance. The rods and caps have no gap between each rod and the crank. And yes I have the pistons and caps going in the right direction. Plus these are the same rods that came off this motor. Now everything is so tight when I tighten the caps the crank won't move. So I'm guessing there must be a torque sequence to tighten caps. I have factory manuals and they don't say nothing about that. Thanks Jerry

 

There's no sequence, you must have something together wrong. Are the rods on the crank in the correct direction? There's a larger chamfer that needs to go towards the radius of the journal, typically numbers or bearing tangs together, and to the outside.

 

Yes I have them going in the right direction. Both the chanfers face each other. I don't understand why they are that tight. Was I supposed to leave the crank lose. All these parts are the same. I use to drive this truck

 

Is it a new crank shaft? When you say the chamfer facing each other that doesn't sound correct.

 

They need to face opposite or away from each other.

 

My problem was they were mislabeled from the machine shop when I had the pistons put on. 1 was 2 and see on. What a way to learn for you first motor. I took all 8 out and put them back in in a hour and the crank turns great. Thanks for the I put

 

I switched them around and they work fine until I torque them down, then I can't move the crank. I pastigage the rod, we'll rod #2 It showed .025. I thought that was good. So I torque them down to 45# then the crank won't turn. What am I doing wrong

 

I assume you mean .0025". Torque them one at a time, and check to see if it turns before torquing another.

 

And yes I meant . 0025. And I torque #2 piston rod and then the crank won't turn. Maybe I have the wrong size bearings. What is the correct clearance. Thanks

 

The bearing and rod has a chamfer on one side of the big end. That side of the rod faces the crank, and the flat side faces the other rod.

 

.0025 is okay for used parts. With a fresh crank and rods I would personally like to see it closer to .002 for a mild street build. It should not bind with .0025.

 

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big chamfer to the crank pin side wall, small chamfer's facing each other. and the same thing follows with the bearing chamfer's , big to the outside, small facing each other. also better to be loose on the clearence than too tight, bearings don't spin from being loose. drag cars use looser clearence, but you need a high volume oil pump if your on the loose end of the clearence. You might have recieved another crank or rods, did you mark them before taking them to the machine shop?, did they grind the crank and recondition the rods? it's common to not get your original stuff back if you are just doing a rebuild, ALWAYS stamp your parts with initials or number that you know. had that happen to me on my first engine 35 years ago. 350 LT1 rods went out, got smog rods in return, but i caught them!

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