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ac55tractor 
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 Topic: Crankshaft end play
Posted: 08 Nov 2021 at 8:30am |
Hi Everyone. I just pulled apart my 1955 Allis B engine. The crankshaft had .070 end play. .044 of that wear was from the thrust bearing. The area of the crank that rides against the thrust bearing was worn back .026. I was able to determine that originally the distance from the back face of the timimg gear to where the crankshaft rides against the back of the thrust bearing is 1.625 from the factory. Now, because of the ware on the crankshaft it now measures 1.651. I sent the crank to the local machine shop. The owner said that he could grind that surface back from .026 to .032 and all I needed to do was to make and install a .032 shim placed between the thrust bearing and the crankshaft to compensate for the difference in order to correct the error. He refused to build it up with weld. He didn't want to be responsible for any damage resulting from welding. I have a small milling machine with a rotary table to make a shim. I am just not so sure about what he suggested or what material to make the shim out of. I hope that I am clear.
Any advice would be appreciated.
Thanks
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steve(ill)
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Posted: 08 Nov 2021 at 8:35am |
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i had a similar problem on a B ... 15 years ago... cant give you exact numbers, but i took the gear off and machined a STEP on the back of the gear so i could push it on about .040 further to get the dimension right for the bearing... you want something small like .002 or .005 clearance .............. The gear is about an inch wide, pushing it on .040 further dont hurt the gear alignment to others.
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ac55tractor
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Posted: 08 Nov 2021 at 8:53am |
That's a great idea. I believe I saw that in an earlier post. I had some questions about that.
I lightly checked hardness of the gear at the teeth with a hand file. It seemed a bit hard to machine. Now thinking about it. I wonder if only the teeth are hardened and the rest of the gear was not, so that's how you were able to machine it.
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steve(ill)
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Posted: 08 Nov 2021 at 8:55am |
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YEP... i remember thinking the same thing when i tried it... Must be soft as i sure dont remember machining being a problem.
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Like them all, but love the "B"s.
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ac55tractor
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Posted: 08 Nov 2021 at 9:02am |
Thanks for the reply. Also in the earlier posts there were different opinions on how to
reinstall the gear. I wasn't sure of the best way to approach that. There is a .003 press fit, and lining up the key way. I would have to get the heat just right.
I have to get outside right now so there maybe a delay in a response. Best to you Steve
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steve(ill)
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Posted: 08 Nov 2021 at 9:21am |
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Seems like i warmed it up maybe 400 degrees with a propane torch and pushed it on.... yea... getting they key aligned is always the trick part..... dont remember, is it a straight key where you can set at the FRONT of the shaft, get the gear and shaft started together, then drive the gear and key on ? ....... again, dont recall a big problem in the install. Heating the gear to expand it does help.
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Like them all, but love the "B"s.
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PaulB
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Posted: 08 Nov 2021 at 10:08am |
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When I send a BE/CE crankshaft to get reground I remove the Crank gear, before I send it This allows the front of the crankshaft to be ground back where the gear presses on to get proper end play. All quality crank grinders should be dong this, any other way is just dong a band-aid fix for something that is messed up.
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If it was fun to pull in LOW gear, I could have a John Deere.
Real pullers don't have speed limits.
If you can't make it GO... make it SHINY
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steve(ill)
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Posted: 08 Nov 2021 at 12:31pm |
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well if your sending off to someone to do the work for you, that would work.. My crank didnt need ground, it just needed the gear pushed on FURTHER... and cutting a step in the gear served that purpose very well.
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ac55tractor
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Posted: 08 Nov 2021 at 1:16pm |
I asked the owner of the automotive machine shop to contact me
before he started so I could stop by here at the forum and get some ideas on how to proceed, before giving him
directions. You guys have great ideas.
Paul, your idea
came to mind just before dropping it off. I pushed the gear off about an
inch and pulled the woodrift key out, hoping that hitting the shaft where the gear butted and reestablishing the 1.625 step over would be a satisfactory option. I was a bit confused over the earlier posts on this subject before posting here today. I guess that I should have stopped by here
first. At that time, I assumed that the gear was too hard to machine.
Thanks Men Steve
Raymond, Maine EIEIO
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ac55tractor
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Posted: 13 Dec 2021 at 11:53am |
I need a second opinion please. I got my crankshaft back from the machine shop just after Thanksgiving. He had to remove .037 to clean up the warn area on the crankshaft. Then he came out to 1.628 (the thickness of the thrust bearing 1.625 plus .003) and then cleaned the face where the gear presses against.
With the crankshaft now pushed out by .037, I was wondering is it going to be necessary to remove .037 from the back of the pulley so that the belt will line up?
Thanks in advance Steve
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SteveM C/IL
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Posted: 13 Dec 2021 at 12:29pm |
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Not for only .037.... .370 maybe. Your only talking 1/32 in
Edited by SteveM C/IL - 13 Dec 2021 at 12:31pm
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steve(ill)
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Posted: 13 Dec 2021 at 3:06pm |
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Steve is right.. you will never see .037 offset.
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Like them all, but love the "B"s.
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ac55tractor
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Posted: 13 Dec 2021 at 3:58pm |
Thanks for the reply's. One less thing to worry about.
I am getting ready to install the bearings. All of the bearing journals are now -.010 except for the center main journal, he had to grind to -.011 to clean it up.
I don’t want to make any mistakes here. Is there an easy explanation on understanding how to get the .002 clearance needed for the bearings on the journals? The original shim thickness was .010 on both the mains and the connecting rods.
In my reading, something was mentioned about being sure to get a .0015 crush on the bearings. How do be sure about maintaining the crush, while adjusting the shims to achieve the .002 bearing clearance on the journals?
Everything else is coming together just fine. I have the oil pump all rebuilt and I finished cleaning the block today.
Steve.
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steve(ill)
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Posted: 13 Dec 2021 at 4:43pm |
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Picture the original shim thickness on the CAPS and the bearing insert installed... The end of the bearing should stick up .001 above the shim if you want .001 CRUSH... Now picture that the bearing clearance is .007 with those shims and your trying to get .002 clearance... So you take out .005 shim pack to get down to .002 clearance.... You ALSO have to file .005 off the end of the bearing to maintain the .001 CRUSH... Go SLOW, be careful, measure...
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steve(ill)
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Posted: 13 Dec 2021 at 4:48pm |
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So i assume you bought .010 NEW bearings for the new crank dimension.. If you put ALL of the original shims in, you should have the same original clearance... Normally you set one of the CAPS with the NEW bearing halves in place and just install the bolts to hold in place, dont CRUNCH them.. Measure the bearing diameter, measure the crank journal, and add .003 -4 shims and install, torque , test... then remove a shim or two as needed.
Edited by steve(ill) - 13 Dec 2021 at 4:52pm
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Like them all, but love the "B"s.
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ac55tractor
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Posted: 13 Dec 2021 at 5:20pm |
Thank you Steve, I understand. Yes new bearings -.010. I had a feeling that I was just
overthinking this a little. I will update as soon as I finish.
I have telescope gauges and micrometers. I think that I can be careful enough not to scratch the inside of the bearing with the telescope gauges. I don't have access to bore gauges any more. The shims were single thickness at .010. So, if I need larger or thinner shims I can make them no problem. I should be good to go. Glad that the forum is here for us all. I have been doing my best to help others with their smaller Allis garden tractors.
Lots of Steve's here.
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ac55tractor
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Posted: 22 Dec 2021 at 11:33pm |
I got my crankshaft back just
after Thanksgiving I have been cleaning parts and taking measurements. Since
then, I ran into a bit of an issue that I cannot explain. Any help here would
be appreciated.
When I disassembled the engine, there were four .008 shims with wings,
installed on one side of every connecting rod.
All the crankshaft journals were ground -.010.
The crankshaft connecting rod journals now measure 1.927.
The connecting rod cap mounted on the rod without the bearings and no
shims, has a diameter of 2.058. This dimension is the same in six places in the
bore.
The new -.010 rod bearing wall thickness is .0645 x 2 = .129
2.058 - .129 = 1.929 theoretical, inside bearing diameter.
You would think that the connecting rod with the bearing diameter of
1.929 installed on the bearing journal diameter of 1.927, will allow .002
clearance on the crankshaft.
I bolted the cap on the
connecting rod with the bearings, for some reason the bearing bore measures
1.925 just either side of the bearing split.
When I placed the connecting
rod with the bearing installed onto the crankshaft. I snugged the cap bolts and
now the connecting rod moves with considerable force, if at all.
I removed the cap and removed
the connecting rod from the crankshaft. There are shiny wear marks on the top,
and bottom halves of the bearing just above and below the split line. The
bottom of the bearing radius was not touched. The connecting rod bearings are
not making full radial contact. They are only making contact on the sides, where the bearing
is split.
I checked clearance on the notches
on the side of the bearing vs the caps. There is .010 clearance.
I tried to add shims where the
bearing is split. The dimension remains
1.925 after shimming.
I tried a piece of plastigage and
got a reading of .003. The cap was only snugged down with a wrench. I am really at a loss here. I hope that I was clear. Thanks in advance
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Lon(MN)
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Posted: 23 Dec 2021 at 7:00am |
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I send the rods out to be resized without shims. I also get them aligned. All the rods I have sent out were egg shaped.
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http://lonsallischalmers.com
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ac55tractor
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Posted: 23 Dec 2021 at 8:25am |
I can take care of that. Thank you very much.
Merry Christmas to everyone !
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steve(ill)
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Posted: 23 Dec 2021 at 8:33am |
You said with the caps on, the bearing bore in the rod is the same in six directions.. I think that tells you the rod is OK, but i agree with Lon, the "can" get egg shaped.
I think in your case what is happening is the bearing is getting "CRUSHED" at the joint between the top and bottom halfs.. Remember the discussion that the bearing shell should stick out .001 past the rod or cap so that it has a small CRUSH ? ..... I would guess you have too much.. I would check that and be temped to relieve some material at the joint so your not squeezing the bearing edges together so much.
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Like them all, but love the "B"s.
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ac55tractor
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Posted: 23 Dec 2021 at 9:09am |
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Thank you Steve (ill) for your reply, I know that I presented a lot of information in my previous post. There was something that I omitted when I posted, that was in my original notes. I carefully read what you said about having the bearing stick out .001 above the shim. I have .006 total sticking out of the bearing halves. When I first installed the rod onto the crankshaft, I used .005 shims to compensate. I was being careful not to remove too much material from the bearing face. That's when I ran into the problem with the bearing being tight on the shaft. After measuring, I ended up with 1.925 just above and below the split. I knew by adding that .006 to the diameter would cause the the bearing to appear out of round. So I placed a new bearing in a cap and set it onto the bearing journal without the connecting rod and got the same result. Where the bearing was only making contact on the sides near the split point, and was difficult to slide on the journal. I measured the width of the bearing inside that cap with a dial vernier. It reads 1.925. For some reason the bearing becomes eccentric when it is installed. I checked the thickness of the bearing with a ball mic. The thickness dimension stays consistent.
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ac55tractor
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Posted: 23 Dec 2021 at 10:06am |
There is something going on with these connecting rods. The bearings were made by Federal Mogul. The mains are fine and everything lined right up with the original shims. I have been trying to figure out what is going on with the connecting rods for almost a month now. I took a lot of measurements and made a lot of notes.
I am considering taking the crankshaft and the connecting rods to the guy that ground the crankshaft and ask his opinion after Christmas. If he doesn't have an answer for me, as a last resort, I was thinking about placing the bearings in the connecting rods. Allow for .001 squeeze, without shims and set the rod onto the rotary table on my milling machine, and mill the bearing to 1.929 diameter. I am looking at removing .002 Babbitt on each side. My only concern is I don't know how thick the Babbitt is.
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Alvin M
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Posted: 23 Dec 2021 at 10:46am |
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My machine shop line bores the block and does the rods then I don't need shims
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steve(ill)
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Posted: 23 Dec 2021 at 12:42pm |
Steve, i think if you stop by and talk to the guy that machined the crank, he might have a good fix. Hopefully you dont have to do it on your milling machine.
Rather than cut a couple thousandths off the ID of the bearing, it might be a better idea to enlarge the hole in the rod so the bearings fit better. ?
Edited by steve(ill) - 23 Dec 2021 at 12:45pm
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ac55tractor
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Posted: 23 Dec 2021 at 1:07pm |
Yes, I can enlarge the hole. Actually that may be a better way to go. I won't have to worry about thinning the Babbitt on the bearing. I really need a break. I have been putting a lot of thought into this since I got the crankshaft back 4 weeks ago. I wanted to be sure that I had all my ducks in a row before returning here with what I had found. I plan on seeing Jeff at the machine shop after Christmas. I have a lot of pictures to share. Is there a limit on the pictures that I can post? This has been a learning experience for me. There are a few things that I wanted to mention. The old front oil seal cut a groove in the crankshaft. By reworking the crankshaft as suggested by the forum, the oil seal will now ride on a fresh spot on the shaft. Also the dirt that came out of the coolant chamber after pulling the piston sleeves was quite a surprise. I know that this forum is the best resource for all things Allis
Chalmers tractors. I appreciate everyone's efforts in helping me out. I
will do my best to nail this down. I really don't want to assemble this
engine and end up with a bunch of parts in a basket. I have had my
Allis B for 30 years. It has been very faithful to me right up until I
pulled the engine last fall. Actually I am surprised that it ran as good
as it did with the warn crankshaft, the warn camshaft, a broken piston
ring in #3 cylinder, not to mention the leaking front and rear
crankshaft seals. Oh boy, did it smoke out of the exhaust. Kept the misquotes away for sure.
Merry Christmas everyone.
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ac55tractor
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Posted: 23 Dec 2021 at 4:52pm |
You know that I wasn't going to quit until I had an answer. Now I do. There is a miss match in the bore on the connecting rod that I was using. So when I originally measured it, I got a "false" larger measurement than what was really there. The cap does not correctly match the rod. It sits off to one side. Maybe the bolts are slightly bent. I snugged the nuts down and I tapped it with a brass hammer until the bore was smooth. I remeasured the bore. It's .005 out of round. Looks like you guys had the right line of thinking. "Thank you". I am going to clean everything up, re-qualify the flats smooth, and re-cut the bores round with no shims. I will let you all know how I make out. I have been a Machinist for over 45 years. I started machining when I was 15. I Just turned 63. I'm sure that I can get it done. Thanks again
Steve from Maine
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steve(ill)
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Posted: 23 Dec 2021 at 6:00pm |
Most do not do that due to time and cost... Being a machinist and "you need the practice"  .. eliminating the shims and boring the rods to size is an excellent idea !
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Like them all, but love the "B"s.
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steve(ill)
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Posted: 23 Dec 2021 at 6:01pm |
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just curious... what kind of lathe / mill machine you got ?
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Like them all, but love the "B"s.
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ac55tractor
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Posted: 23 Dec 2021 at 7:22pm |
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I have a Harbor Freight Mini Mill. Some might say that it's a P.O.S.. I like it. I got it when they were passing out 30% off coupons. I hope that I am not getting carried away here with a bunch of information. I paid $575.00 for it. Regularly $799.99. I have made some serious modifications to it. I have bypassed the cheep plastic gears in the head with a quieter "V" belt drive. I have X, Y, and Z digital readouts. I added a power feed on "X" (Long feed travel). The X has 12 inches of travel. The Y has just over 4 inches of travel. I have added an air piston on the "Z" (up and down travel) and removed the useless spring lever that came with the machine. I am in the process of making a stiffener plate for the back of the machine so I can use my boring head. I have a 6 inch rotary table for it. I made an adapter plate for a 6 inch, 4 Jaw chuck, and a 6 inch, 3 jaw chuck for it. So I can make "most" , but not everything that can be made on a lathe. I have a 4 inch angle lock vice, a 3 inch Hi-Precision Toolmakers Screwless Vise. I have a full set of collets. I have a full set of drill bits and many different size endmills, carbide and high speed. I have a bunch of other tools. Too much to list. I got the machine to keep my skills sharp. I know it's just a toy, But I make good use of it. I made some rings out of aircraft grade Aluminum with Copper bar inlays for gifts. I have made all sorts of parts with it.
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ac55tractor
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Posted: 23 Dec 2021 at 7:40pm |
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