Engine builders or anyone with experience HELP!

[Boss 351]

Okay so this is my second attempt at this so I lack some experience. So here is this 5.0L block, the crank was checked and polished and everything is within spec. I install some new main bearings after everything is cleaned up.

I start with the middle main caps, then move outward. Torquing to about 40lbs and leaving the trust bearing cap at only 10lbs. After this I move the crank in and out a few times with a rubber mallet. I torque everything to spec and in order and the crank siezes. If I loosen ONE bolt at the rear thrust bearing main cap, the crank turns like it's supposed to.

I talked to the machine shop that checked the crank and they reassured that the crank is like new and that there is a problem with the bearing, maybe they aren't correct. Keep in mind that EVERYTHING is standard size on this engine, the crank wasn't grinded down, just polished.

I used some plastiguage for the oil clearence and that is within spec, at the limits but still passable. When I removed everything to check if there was something in the way and I found that the thrust bearing was used (shiny silver) on the edges, 4, 5, and 3 mains were perfect and main #1 was used on the upper bearing, the lower was still grey.

I don't get what's going on... The crank is straight... any ideas please?

 

[Rick 91GT]

What is the thrust clearance?

To set the thrust you need to lube the upper halfs of the bearings, install the crank, put the caps on but only torque #1,#2,#4,#5, leave #3 loose like you did (lube bearings very good), tap the crank as far rearward as it will go, tap it forwards, (check thrust clearance with a dial indicator) and tap the crank all the way rearward, tq the center cap.

Manual Tranny .003"-.005"
Automatic .005"-.007"

Make sure you have the upper and lower bearings in the correct position, the location tangs will be in the wrong place if not.

 

[Boss 351]

AHAHAHA I'm fu cking gay! I installed the thrust bearing on the last main when it's supposed to be on the third!

Jebus fu cking christy! OMG... we learn from our errors, this is one I'll remember for a while. Once I'm done crying I'll start laughing. At least I didn't kill my engine.