Crankshaft won't turn (solved!!)
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Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=125243
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Topic: Crankshaft won't turn (solved!!)
Posted By: BenGiBoy
Subject: Crankshaft won't turn (solved!!)
Date Posted: 30 Jun 2016 at 11:49am
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Hi all, I am assembling a B engine. I put the crankshaft in, put some plastigauge in in top, and installed the bearing cap. Torqued it to spec. (80 ft-lbs, according to my I&T manual) The plastigauge read 0.001 or 0.0015 when I took it off, and that was okay (???) I thought. Besides, the manual said 1-2 for running clearance on the crankshaft. But I torqued the bearing cap bolts down and now I cannot turn the crankshaft even a little bit, trying as hard as I can   (or... as much as the angle will let me try) And I thought that it should be able to turn, even if there is a little bit of resistance. Anyone have any suggestions? Are my bearing clearances too tight? (Need more shims??) Thanks in advance to all that take the time to respond..... (The bearings have plenty of assembly lube on them, btw)
------------- '39 Model B Tractors are cheaper than girls, remember that! |
Replies:
Posted By: Stan IL&TN
Date Posted: 30 Jun 2016 at 11:55am
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Loosen the bearing caps and find out which one is putting it in a bind. Just because each clearance measures fine don't mean the crankshaft is true, meaning it can have a slight offset or bend that makes it wobble until you tighten the caps and then it's in a bind. ------------- 1957 WD45 dad's first AC 1968 one-seventy 1956 F40 Ferguson |
Posted By: BenGiBoy
Date Posted: 30 Jun 2016 at 12:00pm
Okay, I will try that. Will it be okay once the engine is running??? do I need to do anything to it?????? I guess I am just asking when I find which one is causing it to bind, what then? ------------- '39 Model B Tractors are cheaper than girls, remember that! |
Stan IL&TN wrote:Posted By: lowell66dart
Date Posted: 30 Jun 2016 at 12:11pm
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First you have to find the issue: bent crank wrong bearing bad cap etc. ------------- AC 6080 (8030,7060,200,175,D-17HC, 6040,160,6140 all gone) Farmall 1066 & 656 Hi-Clear (for sale), White 2-62 High Clearance, JD 4255 Hi Clear. |
Posted By: injpumpEd
Date Posted: 30 Jun 2016 at 12:33pm
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It should turn easily by hand. Find out where the bind is coming from and correct it, it will not be ok once running! Caps on backward? Wrong positions? Was it a running engine when torn down? Why was it torn down? Crank been stored a long time on it's side, they will bend from their own weight. ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: BenGiBoy
Date Posted: 30 Jun 2016 at 12:58pm
The engine was not running when I took it apart. I think that the caps are on correctly. Maybe I will try turning them around. The crankshaft WAS stored for a couple of months on its side, that might be it. If so, how do I correct it? ----------------------------------------------------------------------------------------------------------- I checked some things, here is what I found: 1. The crank can be turned with any ONE bearing cap torqued to NO MORE THAN 40 ft-lbs. 2. NO two bearing caps can be torqued to ANYTHING or the crank cannot be turned. (the torque wrench will not measure anything less than 20 ft-lbs)
------------- '39 Model B Tractors are cheaper than girls, remember that! |
Posted By: lowell66dart
Date Posted: 30 Jun 2016 at 1:03pm
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If you have a dial indicator you can remove all the caps and see what the runout is at each journal. ------------- AC 6080 (8030,7060,200,175,D-17HC, 6040,160,6140 all gone) Farmall 1066 & 656 Hi-Clear (for sale), White 2-62 High Clearance, JD 4255 Hi Clear. |
Posted By: Brian Jasper co. Ia
Date Posted: 30 Jun 2016 at 1:04pm
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What you need to do after you've verified you have the correct bearings is check the main bearing line bores. I ran into exactly what you describe on my CA engine years ago and had to have the block line bored. You need a machined straight edge the length of the block to do it, otherwise take it to a machine shop that can to a line bore. ------------- "Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford |
Posted By: injpumpEd
Date Posted: 30 Jun 2016 at 1:19pm
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are you positive you have the caps on the correct way? Some engines have the tangs opposite, some same side. Some are stamped with numbers on cam side. How are you determining their proper orientation? Laying on it's side for several months shouldn't have caused any issues. 20 years, maybe lol! ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: Allis dave
Date Posted: 30 Jun 2016 at 1:41pm
| I don't see yet where you said if this crank was freshly ground? Please give a little more history on "not running when took apart" and what you've done to it since then if anything. |
Posted By: DougS
Date Posted: 30 Jun 2016 at 1:47pm
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.001 is a tight clearance. Plastigauge is only giving you the clearance on one small spot on each bearing. If the journal is slightly out of round you might have a negative clearance on other spots. Have you checked to see how out of round the journals are? |
Posted By: BenGiBoy
Date Posted: 30 Jun 2016 at 2:12pm
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To answer both DougS and Allis dave..... the crankshaft was turned at the local NAPA Precision Machine shop when I took it off. The reason for this was that it had a lot of rust pitting and some scratches. 0.030 on the mains, 0.020 on the rods, bearings are the correct size.
What is the 'tang'? I lined them up and looked at the bolt holes, they seemed to be slightly off-center, so I just centered the cap and turned it whatever way the bolt holes lined up. It ended up with all of the part numbers on the caps being oriented so that if the engine is upside down and you are looking at it from a position in front of the engine they are the correct way. Does anyone with a 'B' know if this is the correct way or not? ------------- '39 Model B Tractors are cheaper than girls, remember that! |
Posted By: BenGiBoy
Date Posted: 30 Jun 2016 at 2:13pm
I am not sure what you are talking about, so I don't think that I have one.  ------------- '39 Model B Tractors are cheaper than girls, remember that! |
Posted By: Gerald J.
Date Posted: 30 Jun 2016 at 2:18pm
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Try some oil or grease, like engine assembly grease to lubricate them a bit. Gerald J. |
Posted By: DougS
Date Posted: 30 Jun 2016 at 2:26pm
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Are you using shims on the caps or has the engine been line bored? |
Posted By: Tracy Martin TN
Date Posted: 30 Jun 2016 at 2:40pm
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Make sure you have the rods orientated in correct direction.There is a long side and short side. HTH Tracy
------------- No greater gift than healthy grandkids! |
Posted By: BenGiBoy
Date Posted: 30 Jun 2016 at 3:02pm
They do have assembly lube on them, but good guess.
The engine had been rebuilt in the past, but I do not know if the block was line bored. The bearing clearances that I have were obtained without shims, so I assume it is line bored.
The rods and pistons are not installed yet. Thanks to everyone who has given suggestions so far! ------------- '39 Model B Tractors are cheaper than girls, remember that! |
Posted By: Dick L
Date Posted: 30 Jun 2016 at 3:07pm
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As I read this you only have the main caps on. If so, remove the caps, lift the crankshaft out of the bearings and lube the bearing shells in the block. Set the crankshaft back in the block, Place one cap on at a time. Only torque to 50 or 60 foot pounds turn the crankshaft with only one cap on and tight. If it does not turn place .002 shim under both sides of the bearing cap and try again. Add shims until it turns freely. After you have done one at a time until the crank turn freely with all three tight then remove one cap at a time to use the plastigage at the 80 foot pounds to see what your reading is. Sneak up on it .002 at a time. By doing one at a time pay attention to the other journals looking for an up/down or side movement. I have had these short four cylinder crankshafts stored on there sides for years and have never had one out of spec because of it. If you had snap gages and mices I would advise to put the bearings in without the crankshaft to get the inside diameter and then mike the main journals to get its outside diameter to get the actual clearance. Without the mics you can still get the proper clearance with plastigage but the crankshaft still needs to turn freely and if it is not turning freely you do not have proper clearance some where.
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Posted By: rasman57
Date Posted: 30 Jun 2016 at 3:14pm
| If it has not been line bored previously you need to make sure you understand how that engine was designed to use shims to obtain tolerances. Completely different animal than an ordinary crank, block and caps. You would need to know. If the machine shop just turned and did not line bore because they were not told, you could have a problem. SEE DICK L NOTE BELOW TO UNDERSTAND THE ORIGINAL SHIM DESIGN. |
Posted By: Dick L
Date Posted: 30 Jun 2016 at 3:16pm
Without the block being bored so you do not use shims and you torque you are pinching down on the bearing shell ends. You can only squeeze an orange so tight before the juice has to go somewhere! So the ends of your bearing shells bend in on the crankshaft journals because they have no where else to go. That acts as a brake. Chances are you do not need another set of bearings. Try shimming it and see what happens. I would take two bearing caps and put the shells in like I had in my pictures of how I decided how much to file off to fit a used crankshaft with some wear. You will be able to feel any inward bend if you happened to have some.  |
Posted By: Dick L
Date Posted: 30 Jun 2016 at 3:37pm
| For a novice it would be best to order shim packs to properly shim your engine. they will be needed for both the mains and rods. You put the whole pack in and check with your plastigage and if the clearance is above .002 you can peal .002 off the pack at a time to get the proper clearance. |
Posted By: injpumpEd
Date Posted: 30 Jun 2016 at 4:59pm
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you suppose the crank grinder left too large of a radius in the fillet area? ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: WF owner
Date Posted: 30 Jun 2016 at 5:16pm
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I hate to ask the obvious question, but did you check to make sure you are you using -.030 main bearings?
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Posted By: BenGiBoy
Date Posted: 30 Jun 2016 at 5:43pm
 Yep, these are the correct bearings. ---------------------------------------------------------------------------------------------------------- Thank you to all that helped me figure this out. I tried what DickL suggested, and ignored the bearing clearances for the moment. Installed shims until it spun freely, then checked the clearance. This worked wonderfully, I have them at about 0.020 on the plastigage. I think what happened was just what DickL said, the bearing ends acted as a 'brake'. I did use plastigage, but it just squished untill it could squish no more, then stopped at 0.010, so I thought that it was 'a-okay', but it wasn't. Thanks all! (just a tad embarrassed that I couldn't think of that myself, but other than that, I am happy!!!  )------------- '39 Model B Tractors are cheaper than girls, remember that! |
Posted By: CTuckerNWIL
Date Posted: 30 Jun 2016 at 5:57pm
0.020 Hope your decimal is one place to the right of where it checked 
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: CrestonM
Date Posted: 30 Jun 2016 at 7:41pm
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When I assembled my 8N engine, it was tight. It was hard to crank, and for a couple days cranked hard with the starter, but after that it loosened up some and now works great and has good oil pressure. I just put the crankshaft back in my B, and while it isn't stuck, it's a tad tight, but not as much as the 8N was.
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Posted By: injpumpEd
Date Posted: 30 Jun 2016 at 7:45pm
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I would wet sand in the solvent tank, the bearings that are slightly tight, wayyy before I'd ever put an engine together and let it "loosen up with run time". Just use 600 wet/dry paper, and just very carefully sand with the curvature. Most professional engine builders like to lightly remove the top coating of babbit anyway. ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: CrestonM
Date Posted: 30 Jun 2016 at 7:48pm
| That's interesting. I might try it! |
Posted By: Dick L
Date Posted: 30 Jun 2016 at 8:10pm
Please Don't! You should not even let your unoiled finger touch bearing surface.
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Posted By: desertjoe
Date Posted: 30 Jun 2016 at 9:58pm
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Most professional engine builders like to lightly remove the top coating of babbit anyway. Not wantin to start an argument,,,but I never have heard this secret,,,,,,??? |
Posted By: CrestonM
Date Posted: 30 Jun 2016 at 10:02pm
Ok, I won't do it then! I trust whatever you say. What does touching the bearing with your finger do? I wouldn't think it'd hurt it, but I could be wrong.
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Posted By: Dick L
Date Posted: 30 Jun 2016 at 10:19pm
| If you just washed your hands probly nothing. Most peoples fingers are not all that clean when working on engines. Any small fine dirt on the bearing surface will reduce the life of the bearing. Clean is the answer to long wearing engine parts. Cloth grease rags from a service are not always free of all grit. When I used a service for rags I have cut my hand on a steel shaving on a so called clean rag pulled from the bundle. |
Posted By: OhKen
Date Posted: 01 Jul 2016 at 6:11am
| My guess would of been main caps were either rotated ,if that mistake is even possible , or main caps were installed in wrong sequence . |
Posted By: Dave H
Date Posted: 01 Jul 2016 at 9:42am
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I think it would be interesting to see what the bearings/inserts looked like after a run in on a "tight" engine.
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Posted By: DougS
Date Posted: 01 Jul 2016 at 5:50pm
If it's tight when the engine is cold, it will be tighter when the engine is hot. I wouldn't try it. |
Posted By: Dick L
Date Posted: 01 Jul 2016 at 8:17pm
You are correct! CrestonM needs to take one journal at a time and check for tightness. Then shim where necessary.
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Posted By: Lonn
Date Posted: 02 Jul 2016 at 7:44am
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I think it would be interesting too............ In mechanics school, once every so many years, they would run an engine without oil and sell squares on a board for how long it would run. Like a football board. Now that is interesting. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: DougS
Date Posted: 02 Jul 2016 at 8:09am
Havoline use to run a commercial along those lines. They showed that the engine kept running for X miles, but they didn't say anything about engine damage. I'd liken it to the more recent K&N filter commercial. I wasn't impressed. I wouldn't have bought either vehicle after that. |