rotating assembly resistance and con rod bearing question

folks,

recently doing an full engine rebuild kit on AC B (crank start). with cam/crank in and torque'd to spec with shims, I can easily rotate the crank by hand. Then I started dropping pistons in. with all pistons in and con rod bearing caps on it is quite difficult to crank via the front pulley and hand crank. And that is without torqueing the bearing caps down to spec (90ish ft lbs). I have used shims and even shaved down a few of the connecting rod bearings to no avail. Tried to clean up the rod journals on the crankshaft but it was in pretty bad shape, and possibly marred in some areas. I'm not sure if the issue here is the bearing and bearing cap and clearances or the clearances of the outside edge of the connecting rod and sides of the journal on the crankshaft. Does anyone have any experience with this? Because this is a hand crank I feel I should make it as effortless as possible. It currently takes a LOT of force to rotate the crank via front pulley and breaker bar, and that is without compression. Any suggestions would be welcome.

Back up & start over. If the crank is marred, get it ground. Or at least polished & checked for size.

Ok thanks for the input, I had considered this. Assuming everything goes as it should, what kind of resistance should I feel from the rotating assembly? with or without the pistons in and or compression?

(quoted from post at 09:10:29 10/11/16)
Ok thanks for the input, I had considered this. Assuming everything goes as it should, what kind of resistance should I feel from the rotating assembly? with or without the pistons in and or compression?

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nother possibility: on some engines, there will be interference if rods are facing front vs rear, i.e., flipped 180 from the position they belong in. Have seen & it made engine near impossible to turn.

Ant micrometers involved here ?

Yah I have been using a micrometer in regards to the bearings and shims needed. I guess my next step is to pull the crank and have it spun/polished. I didn't think it was to bad but it sounds like that might be the issue. So then should the end result be me being able to turn it over pretty easily? without compression?

Also, thank you all for the advice, I have a limited knowledge on this stuff and this is my first tractor, late 40's AC B. I know there is a lot of people that have a lifetime of experience with these bad boys, im just trying to tap into that knowledge!

What I would do is take off each cap and place some plastigauge in there and read my clearances off the plastigauge. If you are replacing a standard crank [ unground ] then you need standard bearings. If you sent you crank to be ground the bearings you have now won't fit.

Dealing with shimed rods is difficult even with everything right.

The only additional drag you should encounter is the rings on the cylinder bore. Speaking of rings, did you check the end gaps? That could also be a source of drag if they are too tight.

Back to the rods, there MUST be oil clearance between the crank surface and the rod bearing, usually around .0015" to,0025", but check you specs, don't trust my guessing. If you don't have proper clearance, you will have more problems than just hard to turn. It will seize, spin the bearing, ruin the rod and burn the crank journal! Or if too loose the bearing will pound out until the rod fails.

If the crank is out of round, scored, damaged in any way, you cannot hope to get proper oil clearance. Everything needs to be measured and properly assembled. Now being this is an old style engine, and probably more for show than work, you can get by with less than perfect. But tightening up to the point of being difficult to turn, that is a recipe for disaster! You can do some more shimming, get some Plasti-guage, get some idea where you are on clearance, but be very observant. Try installing one rod assembly, get that one shimed and turning good. Look for strange wear patterns, shiny tight spots, anything that would indicate a miss matched rod cap, out of round rod (that's the trouble with shimmed rods...), be very clean, take your time. Remember, it is much easier to do it right now than to deal with it later when more damage is done and metal shavings are circulating through the oil system.

Crank has to be smooth.

Might as well pull it now and get polished, or you will pick the pieces up off the ground later.

The rods should move freely back and forth once torqued, I do this by hand as a final check, make sure it feels right.

yup, looks like i'll be pulling the crank and starting the process over with new bearings. while we're on the subject. I ordered a full gasket kit and everything is pretty obvious, but on the front crank seal I think they sent me 3 variations of seal. One is a cork which I assume replaces the factory cork which is held in place by a plate and the outer rim of the housing is crimped to keep it in place. One is similar in size with a simple rubber seal that I assume I can pound/press into the "plate" that goes on that side of the engine. And one has both a rubber seal with a spring and a 'felt' type material, but is slightly larger in diameter than the previous ones. Is this just for different applications? I chose to use the cork replacement which worked fine, but would the single rubber seal type worked? didn't seem to seal nearly as tight as the cork, which could only be installed after the plate. Yet again I thank you all for your input!

Please post questions and concerns early if possible. tons of knowledge here willing to help.

(quoted from post at 10:36:17 10/11/16) yup, looks like i'll be pulling the crank and starting the process over with new bearings. while we're on the subject. I ordered a full gasket kit and everything is pretty obvious, but on the front crank seal I think they sent me 3 variations of seal. One is a cork which I assume replaces the factory cork which is held in place by a plate and the outer rim of the housing is crimped to keep it in place. One is similar in size with a simple rubber seal that I assume I can pound/press into the "plate" that goes on that side of the engine. And one has both a rubber seal with a spring and a 'felt' type material, but is slightly larger in diameter than the previous ones. Is this just for different applications? I chose to use the cork replacement which worked fine, but would the single rubber seal type worked? didn't seem to seal nearly as tight as the cork, which could only be installed after the plate. Yet again I thank you all for your input!

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2X checking which way they face. About the gasket set, all sets are put together now so that one set will fit multiple applications/ and variations of any given motor so there should be many extra gaskets.

This is not for everyone but for areas that just need a little cleanup it works great he's using 400 but you can step it down with 600 and even finer. I'm sure you have an out of round tolerance on the crankshaft as well so something you can Consider. Sounds like you may want some professional help in cleaning it up. But as your setting all your clearance tolerance's you will invariably need to clean it up because of the need to install and remove so many times.so this may be helpful to ya. Here's a link
http://www.bing.com/videos/search?q=crankshaft+polishing+utube&view=detail&mid=95EB92B09BED1BF33E3D95EB92B09BED1BF33E3D&FORM=VIRE
Byron

If you get the crank ground and have the rods seized,then have them remove all the shims when they size them.

Use Plastagauge(any auto parts store) to check the clearance on the rod and main bearings.

The rods in that engine are off set and need to be installed properly. Not sure if they will go in wrong however. Here is a sentence from the service manual.
"The connecting rod is off set and must be installed with the long side of off set turned away from the nearest main bearing."
If they can be installed backward there would be a severe drag at the edge of the rod to crankshaft.
Like already said, the only drag should be the rings in the sleeves.
Do you have the service manual? If not you will want to aquire one.
good luck
Dennis