Thrust bearing surface alignment
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From: Mddl A MexCans
Thrust bearing surface alignment
Ok, today I got the crank in. The nails took one of the side seals in with it just a bit even though I followed the proceedure (bent tip away from seal) yada yada... only about a 1/16 below surface..nothing some sealant wont solve I hope.
So onto the issue..As per the instructions in Christs book, I cleaned allthe bearing seats with thinner, installed all the bearings with white grease on top, torqued all but #3 down to 105lb , 20lbs @ shot per bolt per cap, after cap. Then had my brother use a light duty flat pry bar to push the crank forward while I pushed the #3 cap back and then proceeded to torque the # cap while he maintained tension forward on the crank. Semed to go ok until I rotated the crank, now there was a bining while the 3/7 journal was at the bottom of the rotation. I had turned the crank aftertightening the othe caps and all was fine.
I loosened the cap and retorqued it without the proceedure for alignment and it does not bind...
So what do you guys think ?
So onto the issue..As per the instructions in Christs book, I cleaned allthe bearing seats with thinner, installed all the bearings with white grease on top, torqued all but #3 down to 105lb , 20lbs @ shot per bolt per cap, after cap. Then had my brother use a light duty flat pry bar to push the crank forward while I pushed the #3 cap back and then proceeded to torque the # cap while he maintained tension forward on the crank. Semed to go ok until I rotated the crank, now there was a bining while the 3/7 journal was at the bottom of the rotation. I had turned the crank aftertightening the othe caps and all was fine.
I loosened the cap and retorqued it without the proceedure for alignment and it does not bind...
So what do you guys think ?
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Joined: Apr 2004
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It seems obvious that you had the cap jacked one way or the other too far. Barring
the cap to align the surfaces isn't the way I do it. Snug the cap on the trust bearing
down ever so slightly now at some part of the crank other then the thrust bearing
cap bar the crank forward and back then let it relax the cap is where it should be
finish torqueing it. I like when the bearings are in and I can take ahold of the shaft and spin it by hand.
the cap to align the surfaces isn't the way I do it. Snug the cap on the trust bearing
down ever so slightly now at some part of the crank other then the thrust bearing
cap bar the crank forward and back then let it relax the cap is where it should be
finish torqueing it. I like when the bearings are in and I can take ahold of the shaft and spin it by hand.
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From: Mddl A MexCans
Well that is pretty much where it is now. Far from the description in Christs book which seemed a bit odd to start with.
"Place a large screwdriver between the front of one of the main-bearing caps--not the center main!--and one of the crank counterweights. Pry the crankshaft forward in the block. Hold the crankshaft in position. Slip another screwdriver between the front of the center main-bearing cap and the crankshaft. Pry the bearing cap toward the rear of the block. Remove the screwdriver you used to pry the bearing back, but maintain pressure against the one holding the crank forward. Torque the center main-bearing bolts the same as the others. Release the screwdriver once the bolts are tight."
I take it the goal here is to have the faces of the top and bottom halfs of the bearing to mate up flat on the side that faces the rear of the engine. As this is the side which recieves pressure when a load is applied. The bearing if mated correctly will not chew into the crank as it would if they were offset.
"Place a large screwdriver between the front of one of the main-bearing caps--not the center main!--and one of the crank counterweights. Pry the crankshaft forward in the block. Hold the crankshaft in position. Slip another screwdriver between the front of the center main-bearing cap and the crankshaft. Pry the bearing cap toward the rear of the block. Remove the screwdriver you used to pry the bearing back, but maintain pressure against the one holding the crank forward. Torque the center main-bearing bolts the same as the others. Release the screwdriver once the bolts are tight."
I take it the goal here is to have the faces of the top and bottom halfs of the bearing to mate up flat on the side that faces the rear of the engine. As this is the side which recieves pressure when a load is applied. The bearing if mated correctly will not chew into the crank as it would if they were offset.
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