Rotating Assembly
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Joined: Oct 2001
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From: Augusta.GA
Rotating Assembly
I've got my crank and pistons in. Crank caps torqued to 100 ft-lbs. I used green plastiguage on the crank and am between .002 to .0015. with consistent width and no taper except at very front journal. That runs a good 1/2 to 3/4 then tapers some to .001.
The shop manual shows rod side clearance is .010 to .020. I don't have this much except one place is .010. The rest are snug.
Sorry for long lead to question, but when I turn the assembly, how easily should it be rotating? It is very snug and requires some force to turn though there is no binding anywhere.
The shop manual shows rod side clearance is .010 to .020. I don't have this much except one place is .010. The rest are snug.
Sorry for long lead to question, but when I turn the assembly, how easily should it be rotating? It is very snug and requires some force to turn though there is no binding anywhere.
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From: Duncan,OK
The shop manual shows rod side clearance is .010 to .020. I don't have this much except one place is .010. The rest are snug.
Snug as in no clearance?
Sorry for long lead to question, but when I turn the assembly, how easily should it be rotating? It is very snug and requires some force to turn though there is no binding anywhere.
If clearances are good and a good lube was used on assembly ( I prefer STP on the bearings and a good lite weight motor oil the pistons) resistence should be noticable but not heavy. Rotation should be smooth and free from tight spots.
Pat
Snug as in no clearance?
Sorry for long lead to question, but when I turn the assembly, how easily should it be rotating? It is very snug and requires some force to turn though there is no binding anywhere.
If clearances are good and a good lube was used on assembly ( I prefer STP on the bearings and a good lite weight motor oil the pistons) resistence should be noticable but not heavy. Rotation should be smooth and free from tight spots.
Pat
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From: Augusta.GA
Rod Clearance
And thanks for reply...
I'm watching responses before proceeding with rebuild. The rotation is more than resistance, it requires very noticeable force to turn but it stays consistent throughout the revolution.
I'm watching responses before proceeding with rebuild. The rotation is more than resistance, it requires very noticeable force to turn but it stays consistent throughout the revolution.
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From: chicago burbs
snug as in none is not good. very very bad. find out why before you go any farther. the clearance is the space where the oil will be during operation. no clearance, no oil, no operation! max torque to turn a shortblock is 50ft#'s, from my notes from Denver Auto/Deisel. if it requires more than 50ft#'s, find out why before you go any farther.
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From: Augusta.GA
No clearance = Bad
Okiedokie. Stop dead in tracks again.
So why don't I have any clearance? Space should be available but two rods seem to fill space completely. Perhaps shift the crank toward front or back? Maybe out of line somewhat? Please tell me what to do / look for.
From rod to crank = none, rod to rod = none, rod to crank again = none? I'll go look again.
Guy helping said none = good, but I am not pleased with the rotation seems way tight but I have no experience. I will get torque wrench back on it to check the 50#.
Thanks for help
So why don't I have any clearance? Space should be available but two rods seem to fill space completely. Perhaps shift the crank toward front or back? Maybe out of line somewhat? Please tell me what to do / look for.
From rod to crank = none, rod to rod = none, rod to crank again = none? I'll go look again.
Guy helping said none = good, but I am not pleased with the rotation seems way tight but I have no experience. I will get torque wrench back on it to check the 50#.
Thanks for help
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From: iowa
doubt the book says .010 clearence atleast none of mine tell tem to run 10 thousandths clearence that would be WAY too much if you have no clearence my guess is you have the wrong undersize bearing for the rod journals take the rods off, and have the crank journals miked for dia, and then look at the back side of one of the bearings and see where it is. it should say whether it's a .010 undersize or whatever they are.
Just guessing (since I am not there, and can't look myself) your cranks is turned .010 under and your rod bearings are for .020 under size or someithing along those lines, and your right for not wanting to proceed until thats recotified.
edit I just reread your original post your talking side clearence,a nd yes the .010 to .020 is correct, and if it is tighter than that you need to get that corrected or figure out why because if those rods came off that crank to start with they should have that clearence, and if they don't then the machine shop must have done something wrong like putting to much of a radius on the sides of the journal with none radiused bearings this would force the rods together.
Just guessing (since I am not there, and can't look myself) your cranks is turned .010 under and your rod bearings are for .020 under size or someithing along those lines, and your right for not wanting to proceed until thats recotified.
edit I just reread your original post your talking side clearence,a nd yes the .010 to .020 is correct, and if it is tighter than that you need to get that corrected or figure out why because if those rods came off that crank to start with they should have that clearence, and if they don't then the machine shop must have done something wrong like putting to much of a radius on the sides of the journal with none radiused bearings this would force the rods together.
Last edited by monsterbaby; May 29, 2005 at 12:04 PM.
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From: iowa
rereading everything again I have a really dumb question you do know that there is a top, and bottom to the rod bearings, and if you put them on wrong they will force the 2 rods together causing the issue you seem to be having.
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Joined: Oct 2001
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From: Augusta.GA
Rod to Crank Assembled Side Clearance
Monster, thanks for reply.
Want to make sure we are talking same thing. My question is not regarding bearing clearances. I posted values for these to state I believe I'm within tolerance here but welcome verifying it is so. The main bearing to crankshaft clearance allowable shown on my chart is .0008 to .0026. I'm seeing .002-.0015 with little / no taper. This is good right?
My primary concern, is that I have no side clearance... rod to crank (between rods, and each rod side to crank side?). The Rod To Crankshaft Assembled Side Clearance range is .010 to .020. I have none.
Want to make sure we are talking same thing. My question is not regarding bearing clearances. I posted values for these to state I believe I'm within tolerance here but welcome verifying it is so. The main bearing to crankshaft clearance allowable shown on my chart is .0008 to .0026. I'm seeing .002-.0015 with little / no taper. This is good right?
My primary concern, is that I have no side clearance... rod to crank (between rods, and each rod side to crank side?). The Rod To Crankshaft Assembled Side Clearance range is .010 to .020. I have none.
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From: iowa
yes your clearence of .0015-.002 bearing clearence is perfect for your engine. Just to satisfy me if you don't mind... take one of your rod bearings out, and look at it one should say top,and one bottom the one that is top should go on the rod side, bottom on the cap side this is really easy to confuse I have built several hundred engines, and still catch myself on that once in awhile even though I do know better. If it is wrong put them right,a nd recheck, and let me know either way.
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From: Augusta.GA
Top and Bottom to Bearings-- knowing the difference
Monster,
This being my first rebuild I presume I know nothing, and this is more or less accurate since all I know about rebuilding is what I've read.
Having said that, the bottom, I assume means facing oil pan side and top facing head.
The manual says line in top (shows near relief in top) toward front. The badger has a relief hole which I faced toward the front. One side of wrist pin has a stamped "F" which I presume means faces Front (harmonic balancer) and the relief hole is on the side marked with an "F". I would think this would be critical because of "twist" and "bend" tolerances are given for rods.
The crank can only go in one way right? I doubt I got the front and back mixed up, and I've had help doing this, though the guy learned about plastiguage.
So bottom toward oil pan. What about main #3... the bearings are A-1 and A-2. which one toward oil pan. The crank bearings have a top and bottom too? I'll double check 'cause I'm doubting everything now.
This being my first rebuild I presume I know nothing, and this is more or less accurate since all I know about rebuilding is what I've read.
Having said that, the bottom, I assume means facing oil pan side and top facing head.
The manual says line in top (shows near relief in top) toward front. The badger has a relief hole which I faced toward the front. One side of wrist pin has a stamped "F" which I presume means faces Front (harmonic balancer) and the relief hole is on the side marked with an "F". I would think this would be critical because of "twist" and "bend" tolerances are given for rods.
The crank can only go in one way right? I doubt I got the front and back mixed up, and I've had help doing this, though the guy learned about plastiguage.
So bottom toward oil pan. What about main #3... the bearings are A-1 and A-2. which one toward oil pan. The crank bearings have a top and bottom too? I'll double check 'cause I'm doubting everything now.
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From: iowa
the crank bearings also have a top, and bottom but one has an oil hole one doesn't as long as that hole is lined up with the oil hole in the block to allow oil into the bearing those are ok. the main thing with rod bearings is one side is clearenced for the radius on the journal, and one side isn't if they are in backwards then it will push the rods to the center. Another thing on the rods the numbers that are stamped on them at the cap, rod line for which piston they should go to are supposed to be facing outside on the side that pistons sits (I hope that makes sense but if you have #1 on the rod and it's on the passenger side of the block then the numbers should face the passenger side of the block)
and yes the crank will only go in one way.
and yes the crank will only go in one way.
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From: Augusta.GA
getting it right and checking things twice...
Seems similar to something I heard when I was a kid... Anyhoo, thanks for quick replies. We could be on chat we're swapping mail so quickly.
I'm stepping out right now to verify. My help had that end while I was tapping the piston in from the other side. We did talk about top and bottom, but at this point don't want to assume anything and glad you don't either.
While I'm out there and if your still around, what about question concerning whether there is a top and bottom to mains? A-1 and A-2
I'm stepping out right now to verify. My help had that end while I was tapping the piston in from the other side. We did talk about top and bottom, but at this point don't want to assume anything and glad you don't either.
While I'm out there and if your still around, what about question concerning whether there is a top and bottom to mains? A-1 and A-2
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From: iowa
number 1 should be on the passengers side of the block, another way to tell which is number one is looking at the crank #1 will be the one that is in the forward most position on the crank, or if you look at the top of the block you will notice that one side cyl are farther farward by about 1/2" than other the side that is farther forward is the one that has #1, and on a 351/400 that should be the passenger side of the block.
also to your main bearing question A1, A2 not sure which is which by those numbers but the top one tha tgoes into the block will be the one with a hole, and groove in it (I guess I never look at the designations cause the hole HAS to go towards the block to get oil onto the crank.
also to your main bearing question A1, A2 not sure which is which by those numbers but the top one tha tgoes into the block will be the one with a hole, and groove in it (I guess I never look at the designations cause the hole HAS to go towards the block to get oil onto the crank.