fwiw
first things first
pull the crank out of the case so you can work with it easily
1. check the journal with a mic, for out of round, taper and finish,, make sure it is within spec's
2. check both rods ID and make sure they are to spec's, round of course (don't forget to torque them first)
if the rod end is eggshaped (narrow 90degrees from the parting line), add shims to get the bore to round
3. clean the brg shells inside and out, clean the rod bores again, check for lint, grit etc
4. install the upper shell, and push one side down flush, and check the other end at the parting line, it should have a couple thousands of nip.
this provides the needed crush when assembled with the cap and torqued. check the bottom shell as well.
if you have had to add shims to the rod to get it round measure them, and subtract this measurement from the nip of the shells
for instance if you have added .002 shims (two of them, one on each side, 2 x .002=.004)and you have determined that the nip is .006
then you will have the needed .002 nip with the shims installed.
if you have more than the needed .006 then you will need to file down carefully the parting line to reduce to .006
note, the "crush" is needed to lock the brg into the rod when it is torqued and to provide positive heat transfer from the brg to the rod.
5. then assemble the rod w/shells and shims onto the crank journal, with a piece of plastigage across the brg shell on the bottom (weight of the
assembly will open the clearance on the bottom) and torque to spec (do not rotate the assembly),
6. disassemble and check the plastigage to see what you clearance is. if everything was to spec, you should have the .002-.003 clearance.
7. final check is the side clearance just for kicks, use a feeler gage to check between the flange of the shell and the cheek of the journal.
as with anything, careful attention to detail at each step will provide the needed info on where the problem is if there is one, and also assure that
everything fits as it should.
in a perfect world if i found the rod end to be eggshaped and needed shims i would have the rod end honed to spec and perfectly round
and "not" use shim's. shims in my opinion add a level of complexity that need not be there with modern brgs which don't have a thick babbit layer
like the early brg shells had.
if you have a round rod bore end forget the shims and fit the shells to provide the .002 nip and you will be set
as for the main brgs,
this is from many years of setting up tapered roller brgs
i like to set them up with the shims where there is "no" end clearance, none!
set them up so that there is a slight drag when rotating the shaft by hand, if you try to spin it by hand it might make a half revolution.
but feel equal around the full rotation.
the reason is tapered brgs will wear in a bit, the angles of the three elements (inner race, outer race, and rollers) are not perfect
and over a bit of time will wear in a bit and clearance will come about.
a final check is to seat the brg assembly with a block of hardwood and a 4lb hammer, a couple smacks on the end of the crank
with the wood as a protector to provide a bit of shock which will aid in settling the assembly. then recheck the preload of the brgs
spin by hand again to see if things got a bunch more loose,,, if so tear down and reshim accordingly, (wash rinse and repeat)
another check if you are so inclined
use a precision level, and level the crankcase across the deck, shim to get it dead on with whatever you need
then use the level to check the crank to see if it is level in the block as referenced to the deck.
check several times to make sure nothing has moved in your shims under the crankcase
if the deck is level and the crank is level as referenced to the deck you are golden to this point
if however the crank appears to be not level with the deck, then rotate the crank 180 degrees and see if the bubble moves in the opposite direction
if it does move you may have a bent crankshaft, so check on the other end of the crank and see how it works out.
the goal of course is to have the crank dead level with the deck.
if the bubble does not move but the crank is not level with the deck then you will need to determine how best to get it level.
basically follow a logical progression and write down the numbers one step at a time.
bob g
ps, it is late and i need to recheck my "nip" numbers, but the proceedure is correct even if i am off a thou or two