bbc crank end play directions?
03-03-2015, 03:36 AM
#2
Senior Member
RACING JUNKIE
Join Date: Feb 2004
Location: KIEFER, OK.
Posts: 1,312
Here is my method, no matter BBC or SBC. Put all the upper bearings in, having cleaned them all first. Place the crank in the block, check the end play at that point by lightly using a screw driver to move the crank for and aft. I am looking for .006"-.008"
If you have the the end play you are looing for then I put the front cap on and just lightly tighten the bolts/nuts whichever maybe 15lbs-ft. Place the rear cap on and tighten the bolts/nuts to around 20lbs-ft. Take a plastic mallet and hit the crank lightly to move it forward. What this does is align the lower bearing half thrust area to the upper thrust. Re-check your end play. If it is where you want it then you are done. You can take it back apart or go ahead and assemble if that is where you are at.
If you take it back apart then you have to align the thrusts again when you final assemble and re-check end play.
If you do not have enough end play when you first check, you can take the bearing half out, get some 1500grit wet or dry sand paper, place it on glass or a surface plate with some light oil on it and slowly sand the thrust area in a figure 8 pattern. Measure the thickness of it before you start sanding so you know how much to take off. It usually doesn't take much and try not to tilt the bearing as you do it. Then check end play again for that half. When it is right, do the same for the other half.
That is my method in a nut shell.
Curtis
If you have the the end play you are looing for then I put the front cap on and just lightly tighten the bolts/nuts whichever maybe 15lbs-ft. Place the rear cap on and tighten the bolts/nuts to around 20lbs-ft. Take a plastic mallet and hit the crank lightly to move it forward. What this does is align the lower bearing half thrust area to the upper thrust. Re-check your end play. If it is where you want it then you are done. You can take it back apart or go ahead and assemble if that is where you are at.
If you take it back apart then you have to align the thrusts again when you final assemble and re-check end play.
If you do not have enough end play when you first check, you can take the bearing half out, get some 1500grit wet or dry sand paper, place it on glass or a surface plate with some light oil on it and slowly sand the thrust area in a figure 8 pattern. Measure the thickness of it before you start sanding so you know how much to take off. It usually doesn't take much and try not to tilt the bearing as you do it. Then check end play again for that half. When it is right, do the same for the other half.
That is my method in a nut shell.
Curtis
